Update Trans docs with new concurrency rules

Also add support for bare TCP

cmd/hopp-generate/main.go

@@ -1,48 +1,66 @@
 package main
 
 import "os"
-import "fmt"
 import "strings"
 import "path/filepath"
+import "git.tebibyte.media/sashakoshka/go-cli"
 import "git.tebibyte.media/sashakoshka/goparse"
 import "git.tebibyte.media/sashakoshka/hopp/generate"
 
 func main() {
-	name := os.Args[0]
-	if len(os.Args) != 3 {
-		fmt.Fprintf(os.Stderr, "Usage: %s SOURCE DESTINATION\n", name)
+	flagOutput      := cli.NewInputFlag('o', "output", "The output file", "", cli.ValString)
+	flagPackageName := cli.NewInputFlag('p', "package-name", "The package name of the file", "", cli.ValString)
+	command := cli.New("Compile PDL files to program source code",
+		flagOutput,
+		flagPackageName)
+	command.Syntax = "FILE [OPTIONS]..."
+	command.ParseOrExit(os.Args)
+
+	if len(command.Args) != 1 {
+		command.Usage()
 		os.Exit(2)
 	}
-	source      := os.Args[1]
-	destination := os.Args[2]
+	source      := command.Args[0]
+	destination := flagOutput.Value
+	if destination == "" {
+		destination = "protocol.go"
+	}
 
 	input, err := os.Open(source)
-	handleErr(1, err)
+	handleErr(command, 1, err)
 	defer input.Close()
 	protocol, err := generate.ParseReader(source, input)
-	handleErr(1, err)
+	handleErr(command, 1, err)
 
-	absDestination, err := filepath.Abs(destination)
-	handleErr(1, err)
-	packageName := cleanPackageName(strings.ReplaceAll(
-		strings.ToLower(filepath.Base(absDestination)),
-		" ", "_"))
-	destination = filepath.Join(os.Args[2], "generated.go")
+	packageName := flagPackageName.Value
+	if packageName == "" {
+		absDestination, err := filepath.Abs(destination)
+		handleErr(command, 1, err)
+		base := filepath.Base(absDestination)
+		if scrounged, ok := scroungeForPackageName(filepath.Dir(absDestination)); ok {
+			packageName = scrounged
+		} else {
+			packageName = strings.ReplaceAll(
+				strings.ToLower(base),
+				" ", "_")
+		}
+	}
+	packageName = cleanPackageName(packageName)
 
 	output, err := os.Create(destination)
-	handleErr(1, err)
+	handleErr(command, 1, err)
 	generator := generate.Generator {
 		Output:      output,
 		PackageName: packageName,
 	}
 	_, err = generator.Generate(protocol)
-	handleErr(1, err)
-	fmt.Fprintf(os.Stderr, "%s: OK\n", name)
+	handleErr(command, 1, err)
+	command.Println(destination, "OK")
 }
 
-func handleErr(code int, err error) {
+func handleErr(command *cli.Cli, code int, err error) {
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "%s: %v\n", os.Args[0], parse.Format(err))
+		command.Errorln(parse.Format(err))
 		os.Exit(code)
 	}
 }
@@ -61,3 +79,32 @@ func cleanPackageName(str string) string {
 	}
 	return string(buffer[:j])
 }
+
+func scroungeForPackageName(dir string) (string, bool) {
+	entries, err := os.ReadDir(dir)
+	if err != nil { return "", false}
+	for _, entry := range entries {
+		if !entry.Type().IsRegular() { continue }
+		file, err := os.Open(filepath.Join(dir, entry.Name()))
+		if err != nil { continue }
+		defer file.Close()
+		// FIXME: it is entirely possible that the only file will have
+		// a shitload of doc comments preceeding the package name, and
+		// those comments are usually huge so this is bad
+		buffer := [512]byte { }
+		n, _ := file.Read(buffer[:])
+		text := string(buffer[:n])
+
+		packageIndex := strings.Index(text, "package")
+		if packageIndex < 0 { continue }
+		text = text[packageIndex:]
+		
+		newlineIndex := strings.Index(text, "\n")
+		if packageIndex > 0 { text = text[:newlineIndex] }
+
+		fields := strings.Fields(text)
+		if len(fields) < 2 { continue }
+		return fields[1], true
+	}
+	return "", false
+}

connection.go

@@ -34,8 +34,8 @@ type Conn interface {
 }
 
 // Trans is a HOPP transaction. Methods of this interface are not safe for
-// concurrent use with the exception of the Close and ID methods. The
-// recommended use case is one goroutine per transaction.
+// concurrent use with the exception of the Write, SendWriter, Close, and ID
+// methods. The recommended use case is one goroutine per transaction.
 type Trans interface {
 	// Close closes the transaction. Any blocked operations will be
 	// unblocked and return errors. This method is safe for concurrent use.
@@ -45,13 +45,13 @@ type Trans interface {
 	// unique within the connection. This method is safe for concurrent use.
 	ID() int64
 		
-	// Send sends a message. This method is not safe for concurrent use.
+	// Send sends a message. This method is safe for concurrent use.
 	Send(method uint16, data []byte) error
 	// SendWriter sends data written to an [io.Writer]. The writer must be
 	// closed after use. Closing the writer flushes any data that hasn't
 	// been written yet. Any writer previously opened through this function
-	// will be discarded. This method is not safe for concurrent use, and
-	// neither is its result.
+	// will be discarded. This method is safe for concurrent use, but its
+	// result isn't.
 	SendWriter(method uint16) (io.WriteCloser, error)
 	// Receive receives a message. This method is not safe for concurrent
 	// use.

design/pdl-language.md

@@ -6,7 +6,7 @@ PDL allows defining a protocol using HOPP and TAPE.
 
 | Syntax     | TN      | CN | Description
 | ---------- | ------- | -: | -----------
-| I5         | SI      |    |   
+| I5         | SI      |    | 
 | I8         | LSI     |  0 | 
 | I16        | LSI     |  1 | 
 | I32        | LSI     |  3 | 
@@ -25,6 +25,7 @@ PDL allows defining a protocol using HOPP and TAPE.
 | F64        | FP      |  7 | 
 | F128[^2]   | FP      | 15 | 
 | F256[^2]   | FP      | 31 | 
+| Bool       | SI      |    | 
 | String     | SBA/LBA |  * | UTF-8 string
 | Buffer     | SBA/LBA |  * | Byte array
 | []\<TYPE\> | OTA     |  * | Array of any type[^1]
@@ -32,6 +33,11 @@ PDL allows defining a protocol using HOPP and TAPE.
 | {...}      | KTV     |  * | Table with defined schema
 | Any        | *       |  * | Value of an undefined type
 
+Tables with a defined schema can specify some fields as optional using a
+question mark before the type. This will wrap the field the go-util
+ucontainer.Option type. When encoding, void fields will not be included in the
+output, and when decoding, unspecified fields are left void.
+
 [^1]: Excluding SI and SBA. I5 and U5 cannot be used in an array, but String and
 Buffer are simply forced to use their "long" variant.
 
@@ -47,11 +53,13 @@ structures. They are separated by whitespace.
 | Method   | `M[0-9A-Fa-f]{4}`  | A 16-bit hexadecimal method code.
 | Key      | `[0-9A-Fa-f]{4}`   | A 16-bit hexadecimal table key.
 | Ident    | `[A-Z][A-Za-z0-9]` | An identifier.
+| Option   | `?`                | A question mark.
 | Comma    | `,`                | A comma separator.
 | LBrace   | `{`                | A left curly brace.
 | RBrace   | `}`                | A right curly brace.
 | LBracket | `[`                | A left square bracket.
 | RBracket | `]`                | A right square bracket.
+| Comment  | `\/\/.*$`          | A doc comment starting with a double-slash.
 
 ## Syntax
 
@@ -68,18 +76,27 @@ an Ident token respectively. A message consists of the method code (Method), the
 message name (Ident), and the message's root type. This is usually a table, but
 can be anything.
 
+Messages, types, and table fields can all have doc comments preceding them,
+which are used to generate documentation for the protocol. The syntax is the
+same as Go's (for now). Comments aren't allowed anywhere else.
+
 Here is an example of all that:
 
 ```
+// Connect is sent from the client to the server as the first message of an
+// authenticated transaction.
 M0000 Connect {
 	0000 Name String,
 	0001 Password String,
 }
 
+// UserList is sent from the server to the client in response to a Connect
+// message.
 M0001 UserList {
 	0000 Users []User,
 }
 
+// User holds profile information about a single user.
 User {
 	0000 Name      String,
 	0001 Bio       String,
@@ -96,10 +113,10 @@ Below is an EBNF description of the language.
 <method>  -> /M[0-9A-Fa-f]{4}/
 <key>     -> /[0-9A-Fa-f]{4}/
 <ident>   -> /[A-Z][A-Za-z0-9]/
-<field>   -> <key> <ident> <type>
+<field>   -> <key> <ident> ["?"] <type>
 <type> -> <ident>
         | "[" "]" <type>
-        | "{" (<field> ",")* [<field>] "}"
-<message> -> <method> <ident> <type>
-<typedef> -> <ident> <type>
+        | "{" (<comment>* <field> ",")* [<comment>* <field>] "}"
+<message> -> <comment>* <method> <ident> <type>
+<typedef> -> <comment>* <ident> <type>
 ```

design/protocol.md

@@ -132,6 +132,8 @@ METADAPT-B is used over QUIC for communication over networks such as the
 Internet.
 
 ### METADAPT-A
+![Diagram of a METADAPT-A MMB.](../assets/metadapt-a-mmb-diagram.png)
+
 METADAPT-A requires a transport which offers a single full-duplex data stream
 that persists for the duration of the connection. All transactions are
 multiplexed onto this single stream. Each MMB contains a 12-octet long header,

dial.go

@@ -5,38 +5,59 @@ import "errors"
 import "context"
 import "crypto/tls"
 
-// Dial opens a connection to a server. The network must be one of "quic",
-// "quic4", (IPv4-only) "quic6" (IPv6-only), or "unix". For now, "quic4" and
-// "quic6" don't do anything as the quic-go package doesn't seem to support this
-// behavior.
-func Dial(ctx context.Context, network, address string) (Conn, error) {
-	return (Dialer { }).Dial(ctx, network, address)
-}
-
-// Dialer allows for further configuration of the dialing process.
-type Dialer struct {
-	TLSConfig *tls.Config
-}
-
-// Dial opens a connection to a server. The network must be one of "quic",
-// "quic4", (IPv4-only) "quic6" (IPv6-only), or "unix". For now, quic is not
-// supported.
-func (diale Dialer) Dial(ctx context.Context, network, address string) (Conn, error) {
+// Dial opens a connection to a server. The network must be one of:
+// 
+// - "quic"
+// - "quic4" (IPv4-only)
+// - "quic6" (IPv6-only)
+// - "tls"
+// - "tls4" (IPv4-only)
+// - "tls6" (IPv6-only)
+// - "tcp"
+// - "tcp4" (IPv4-only)
+// - "tcp6" (IPv6-only)
+// - "unix"
+//
+// For now, QUIC is unsupported.
+func Dial(ctx context.Context, network, address string, tlsConf *tls.Config) (Conn, error) {
 	switch network {
-	case "quic", "quic4", "quic6": return diale.dialQUIC(ctx, network, address)
-	case "unix":                   return diale.dialUnix(ctx, network, address)
+	case "quic", "quic4", "quic6": return DialQUIC(ctx, network, address, tlsConf)
+	case "tls", "tls4", "tls6":    return DialTLS(ctx, network, address, tlsConf)
+	case "tcp", "tcp4", "tcp6":
+		addr, err := net.ResolveTCPAddr(network, address)
+		if err != nil { return nil, err }
+		return DialTCP(ctx, network, nil, addr)
+	case "unix":
+		addr, err := net.ResolveUnixAddr(network, address)
+		if err != nil { return nil, err }
+		return DialUnix(ctx, network, addr)
 	default:                       return nil, ErrUnknownNetwork
 	}
 }
 
-func (diale Dialer) dialQUIC(ctx context.Context, network, address string) (Conn, error) {
+// DialQUIC opens a connection to a server over QUIC.
+func DialQUIC(ctx context.Context, network, address string, tlsConf *tls.Config) (Conn, error) {
 	return nil, errors.New("quic is not yet implemented")
 }
 
-func (diale Dialer) dialUnix(ctx context.Context, network, address string) (Conn, error) {
-	if network != "unix" { return nil, ErrUnknownNetwork }
-	addr, err := net.ResolveUnixAddr(network, address)
+// DialTLS opens a connection to a server over TLS.
+func DialTLS(ctx context.Context, network, address string, tlsConf *tls.Config) (Conn, error) {
+	network, err := tlsNetworkToTCPNetwork(network)
 	if err != nil { return nil, err }
+	conn, err := tls.Dial(network, address, tlsConf)
+	if err != nil { return nil, err }
+	return AdaptA(conn, ClientSide), nil
+}
+
+// DialTCP opens a connection to a server over TCP.
+func DialTCP(ctx context.Context, network string, laddr, raddr *net.TCPAddr) (Conn, error) {
+	conn, err := net.DialTCP(network, laddr, raddr)
+	if err != nil { return nil, err }
+	return AdaptA(conn, ClientSide), nil
+}
+
+// DialUnix opens a connection to a server over a Unix domain socket.
+func DialUnix(ctx context.Context, network string, addr *net.UnixAddr) (Conn, error) {
 	conn, err := net.DialUnix(network, nil, addr)
 	if err != nil { return nil, err }
 	return AdaptA(conn, ClientSide), nil
@@ -54,7 +75,6 @@ func tlsConfig(conf *tls.Config) *tls.Config {
 	return conf
 }
 
-
 func quicNetworkToUDPNetwork(network string) (string, error) {
 	switch network {
 	case "quic4": return "udp4", nil
@@ -63,3 +83,12 @@ func quicNetworkToUDPNetwork(network string) (string, error) {
 	default:      return "", ErrUnknownNetwork
 	}
 }
+
+func tlsNetworkToTCPNetwork(network string) (string, error) {
+	switch network {
+	case "tls4": return "tcp4", nil
+	case "tls6": return "tcp6", nil
+	case "tls":  return "tcp",  nil
+	default:      return "", ErrUnknownNetwork
+	}
+}

examples/1proc/main.go

@@ -0,0 +1,86 @@
+package main
+
+import "io"
+import "log"
+import "time"
+import "errors"
+import "context"
+import "git.tebibyte.media/sashakoshka/hopp"
+
+var network = "tcp"
+var addr    = "localhost:7959"
+
+func main() {
+	go func() {
+		defer log.Println("SERVER closing")
+		
+		listener, err := hopp.Listen(network, addr, nil)
+		if err != nil { log.Println("SERVER", err); return }
+		log.Println("SERVER listening")
+		conn, err := listener.Accept()
+		if err != nil { log.Println("SERVER", err); return }
+		defer conn.Close()
+		
+		trans, err := conn.AcceptTrans()
+		if err != nil { log.Println("SERVER", err); return }
+		defer trans.Close()
+
+		for {
+			method, data, err := trans.Receive()
+			if err != nil { log.Println("SERVER", err); return }
+			log.Println("SERVER got", method, data)
+			log.Println("SERVER send", method, data)
+			err = trans.Send(1, data[:])
+			if err != nil { log.Println("SERVER", err); return }
+		}
+	}()
+
+	time.Sleep(time.Second * 2)
+	
+	func() {
+		log.Println("CLIENT dialing")
+		conn, err := hopp.Dial(context.Background(), network, addr, nil)
+		if err != nil { log.Fatalln("CLIENT", err) }
+		log.Println("CLIENT dialed")
+		
+		trans, err := conn.OpenTrans()
+		if err != nil {
+			log.Println("CLIENT", err)
+			return
+		}
+
+		go func() {
+			for {
+				method, data, err := trans.Receive()
+				if err != nil {
+					if !errors.Is(err, io.EOF) {
+						log.Printf("CLIENT failed to receive message: %v", err)
+					}
+					return
+				}
+				log.Println("CLIENT got", method, data)
+			}
+		}()
+		
+		data := [1]byte { }
+		for {
+			log.Println("CLIENT send", 1, data)
+			err := trans.Send(1, data[:])
+			if err != nil {
+				log.Println("CLIENT", err)
+				return
+			}
+			data[0] ++
+			time.Sleep(time.Second)
+		}
+		
+		log.Println("CLIENT waiting for connection close...")
+		trans, err = conn.AcceptTrans()
+		if !errors.Is(err, io.EOF) {
+			log.Println("CLIENT wrong error:", err)
+			log.Fatalln("CLIENT trans:", trans)
+		}
+		log.Println("CLIENT DONE")
+		conn.Close()
+	}()
+}

examples/chat/client/main.go

@@ -1,9 +1,11 @@
 package main
 
 import "os"
+import "io"
 import "fmt"
 import "time"
 import "bufio"
+import "errors"
 import "context"
 import "crypto/tls"
 import "git.tebibyte.media/sashakoshka/hopp"
@@ -17,11 +19,12 @@ func main() {
 	}
 	address := os.Args[1]
 	room    := os.Args[2]
-	var nickname hopp.Option[string]; if len(os.Args) >= 4 {
-		nickname = hopp.O(os.Args[3])
+	nickname := "Anonymous"; if len(os.Args) >= 4 {
+		nickname = os.Args[3]
 	}
 	trans, err := join(address, room, nickname)
 	handleErr(1, err)
+	fmt.Fprintf(os.Stdout, "(i) connected to %s/%s\n", address, room)
 	go func() {
 		reader := bufio.NewReader(os.Stdin)
 		for {
@@ -31,67 +34,49 @@ func main() {
 		}
 	}()
 	for {
-		message, err := chat.Receive(trans)
-		handleErr(1, err)
-		switch message := message.(type) {
-		case *chat.MessageChat:
-			nickname := "Anonymous"
-			if value, ok := message.Nickname.Get(); ok {
-				nickname = value
+		message, _, err := chat.Receive(trans)
+		if err != nil {
+			if !errors.Is(err, io.EOF) {
+				handleErr(1, err)
 			}
-			fmt.Fprintf(os.Stdout, "%s: %s\n", nickname, message.Content)
-		case *chat.MessageJoinNotify:
+			break
+		}
+		switch message := message.(type) {
+		case chat.MessageChat:
+			fmt.Fprintf(os.Stdout, "%s: %s\n", message.Nickname, message.Content)
+		case chat.MessageJoinNotify:
 			fmt.Fprintf(os.Stdout, "(i) %s joined the room\n", message.Nickname)
-		case *chat.MessageLeaveNotify:
+		case chat.MessageLeaveNotify:
 			fmt.Fprintf(os.Stdout, "(i) %s left the room\n", message.Nickname)
 		}
 	}
+	fmt.Fprintf(os.Stdout, "(i) disconnected\n")
 }
 
-func join(address string, room string, nickname hopp.Option[string]) (hopp.Trans, error) {
+func join(address string, room string, nickname string) (hopp.Trans, error) {
 	ctx, done := context.WithTimeout(context.Background(), 16 * time.Second)
 	defer done()
-	dialer := hopp.Dialer {
-		TLSConfig: &tls.Config {
-			// don't actually do this in real life
-			InsecureSkipVerify: true,
-		},
-	}
-	conn, err := dialer.Dial(ctx, "quic", address)
-	if err != nil { return nil, err }
-
-	err = updateProfile(conn, nickname)
+	conn, err := hopp.Dial(ctx, "tls", address, &tls.Config {
+		// don't actually do this in real life
+		InsecureSkipVerify: true,
+	})
 	if err != nil { return nil, err }
 	
 	transRoom, err := conn.OpenTrans()
 	if err != nil { return nil, err }
-	err = chat.Send(transRoom, &chat.MessageJoin {
-		Room: room,
+	_, err = chat.Send(transRoom, &chat.MessageJoin {
+		Room:     room,
+		Nickname: nickname,
 	})
 	if err != nil { return nil, err }
 	return transRoom, nil
 }
 
 func send(trans hopp.Trans, content string) error {
-	return chat.Send(trans, &chat.MessageChat {
+	_, err := chat.Send(trans, &chat.MessageChat {
 		Content: content,
 	})
-}
-
-func updateProfile(conn hopp.Conn, nickname hopp.Option[string]) error {
-	trans, err := conn.OpenTrans()
-	if err != nil { return err }
-	defer trans.Close()
-	err = chat.Send(trans, &chat.MessageUpdateProfile {
-		Nickname: nickname,
-	})
-	if err != nil { return err }
-	message, err := chat.Receive(trans)
-	if err != nil { return err }
-	switch message := message.(type) {
-	case *chat.MessageError: return message
-	default:                 return nil
-	}
+	return err
 }
 
 func handleErr(code int, err error) {

examples/chat/doc.go

@@ -1,6 +1,6 @@
-// Package chat implements a simple chat protocol over HOPP. To re-generate the
-// source files, run this command from within the root directory of the
-// repository:
-//
-//   go run ./cmd/hopp-generate examples/chat/protocol.md examples/chat/protocol
+// Package chat demonstrates a simple chat protocol.
 package chat
+
+// To use this in your own project, replace "go run ../../cmd/hopp-generate"
+// with just "hopp-generate".
+//go:generate go run ../../cmd/hopp-generate protocol.pdl -o protocol.go

examples/chat/error.go

@@ -3,8 +3,8 @@ package chat
 import "fmt"
 
 func (msg *MessageError) Error() string {
-	if description, ok := msg.Description.Get(); ok {
-		return fmt.Sprintf("other party sent error: %d %s", msg.Error, description)
+	if description, ok := msg.Description.Value(); ok {
+		return fmt.Sprintf("other party sent error: %d %s", msg.Code, description)
 	} else {
 		return fmt.Sprintf("other party sent error: %d", msg.Code)
 	}

examples/chat/generated.go

@@ -1,369 +0,0 @@
-package chat
-
-import "git.tebibyte.media/sashakoshka/hopp"
-import "git.tebibyte.media/sashakoshka/hopp/tape"
-
-// Send sends one message along a transaction.
-func Send(trans hopp.Trans, message hopp.Message) error {
-	buffer, err := message.MarshalBinary()
-	if err != nil { return err }
-	return trans.Send(message.Method(), buffer)
-}
-
-// Receive receives one message from a transaction.
-func Receive(trans hopp.Trans) (hopp.Message, error) {
-	method, data, err := trans.Receive()
-	if err != nil { return nil, err }
-	switch method {
-	case 0x0000:
-		message := &MessageError { }
-		err := message.UnmarshalBinary(data)
-		if err != nil { return nil, err }
-		return message, nil
-	case 0x0001:
-		message := &MessageSuccess { }
-		err := message.UnmarshalBinary(data)
-		if err != nil { return nil, err }
-		return message, nil
-	case 0x0100:
-		message := &MessageUpdateProfile { }
-		err := message.UnmarshalBinary(data)
-		if err != nil { return nil, err }
-		return message, nil
-	case 0x0200:
-		message := &MessageJoin { }
-		err := message.UnmarshalBinary(data)
-		if err != nil { return nil, err }
-		return message, nil
-	case 0x0201:
-		message := &MessageChat { }
-		err := message.UnmarshalBinary(data)
-		if err != nil { return nil, err }
-		return message, nil
-	case 0x0300:
-		message := &MessageJoinNotify { }
-		err := message.UnmarshalBinary(data)
-		if err != nil { return nil, err }
-		return message, nil
-	case 0x0301:
-		message := &MessageLeaveNotify { }
-		err := message.UnmarshalBinary(data)
-		if err != nil { return nil, err }
-		return message, nil
-	default: return nil, hopp.ErrUnknownMethod
-	}
-}
-
-// (0) Error is sent by a party when the other party has done something erroneous. The valid error codes are:
-// 
-// 0: General, unspecified error
-// 
-// The description field, if specified, determines a human-readable error to be shown to the user. The sending party must immediately close the transaction after this message is sent.
-type MessageError struct {
-	/* 0 */ Code uint16
-	/* 1 */ Description hopp.Option[string]
-}
-
-// Method returns the method number of the message.
-func (msg MessageError) Method() uint16 {
-	return 0
-}
-
-// MarshalBinary encodes the data in this message into a buffer.
-func (msg *MessageError) MarshalBinary() ([]byte, error) {
-	size  := 0
-	count := 1
-	offsetCode := size
-	{	value := msg.Code
-		size += 2; _ = value }
-	offsetDescription := size
-	if value, ok := msg.Description.Get(); ok {
-		count ++
-		size += len(value) }
-	if size  > 0xFFFF { return nil, hopp.ErrPayloadTooLarge}
-	if count > 0xFFFF { return nil, hopp.ErrPayloadTooLarge}
-	buffer := make([]byte, 2 + 4 * count + size)
-	tape.EncodeI16(buffer[:2], uint16(count))
-	{	value := msg.Code
-		tape.EncodeI16(buffer[offsetCode:], value)}
-	if value, ok := msg.Description.Get(); ok {
-		tape.EncodeString(buffer[offsetDescription:], value)}
-	return buffer, nil
-}
-
-// UnmarshalBinary dencodes the data from a buffer int this message.
-func (msg *MessageError) UnmarshalBinary(buffer []byte) error {
-	pairs, err := tape.DecodePairs(buffer)
-	if err != nil { return err }
-	foundRequired := 0
-	for tag, data := range pairs {
-		switch tag {
-		case 0:
-			value, err := tape.DecodeI16[uint16](data)
-			if err != nil { return err }
-			msg.Code = value
-			foundRequired ++
-		case 1:
-			value, err := tape.DecodeString[string](data)
-			if err != nil { return err }
-			msg.Description = hopp.O(value)
-		}
-	}
-	if foundRequired != 1 { return hopp.ErrTablePairMissing }
-	return nil
-}
-
-// (1) Success is sent by a party when it has successfully completed a task given to it by the other party. The sending party must immediately close the transaction after this message is sent.
-type MessageSuccess struct {
-}
-
-// Method returns the method number of the message.
-func (msg MessageSuccess) Method() uint16 {
-	return 1
-}
-
-// MarshalBinary encodes the data in this message into a buffer.
-func (msg *MessageSuccess) MarshalBinary() ([]byte, error) {
-	size  := 0
-	count := 0
-	if size  > 0xFFFF { return nil, hopp.ErrPayloadTooLarge}
-	if count > 0xFFFF { return nil, hopp.ErrPayloadTooLarge}
-	buffer := make([]byte, 2 + 4 * count + size)
-	tape.EncodeI16(buffer[:2], uint16(count))
-	return buffer, nil
-}
-
-// UnmarshalBinary dencodes the data from a buffer int this message.
-func (msg *MessageSuccess) UnmarshalBinary(buffer []byte) error {
-	// no fields
-	return nil
-}
-
-// (256) UpdateProfile is sent by the client in a new transaction to update the profile details that will be shown to other connected clients.
-type MessageUpdateProfile struct {
-	/* 0 */ Nickname hopp.Option[string]
-}
-
-// Method returns the method number of the message.
-func (msg MessageUpdateProfile) Method() uint16 {
-	return 256
-}
-
-// MarshalBinary encodes the data in this message into a buffer.
-func (msg *MessageUpdateProfile) MarshalBinary() ([]byte, error) {
-	size  := 0
-	count := 0
-	offsetNickname := size
-	if value, ok := msg.Nickname.Get(); ok {
-		count ++
-		size += len(value) }
-	if size  > 0xFFFF { return nil, hopp.ErrPayloadTooLarge}
-	if count > 0xFFFF { return nil, hopp.ErrPayloadTooLarge}
-	buffer := make([]byte, 2 + 4 * count + size)
-	tape.EncodeI16(buffer[:2], uint16(count))
-	if value, ok := msg.Nickname.Get(); ok {
-		tape.EncodeString(buffer[offsetNickname:], value)}
-	return buffer, nil
-}
-
-// UnmarshalBinary dencodes the data from a buffer int this message.
-func (msg *MessageUpdateProfile) UnmarshalBinary(buffer []byte) error {
-	pairs, err := tape.DecodePairs(buffer)
-	if err != nil { return err }
-	foundRequired := 0
-	for tag, data := range pairs {
-		switch tag {
-		case 0:
-			value, err := tape.DecodeString[string](data)
-			if err != nil { return err }
-			msg.Nickname = hopp.O(value)
-		}
-	}
-	if foundRequired != 1 { return hopp.ErrTablePairMissing }
-	return nil
-}
-
-// (512) Join is sent by the client when it wishes to join a room. It must begin a new transaction, and that transaction will persist while the user is in that room. Messages having to do with the room will be sent along this transaction. To leave the room, the client must close the transaction.
-type MessageJoin struct {
-	/* 0 */ Room string
-}
-
-// Method returns the method number of the message.
-func (msg MessageJoin) Method() uint16 {
-	return 512
-}
-
-// MarshalBinary encodes the data in this message into a buffer.
-func (msg *MessageJoin) MarshalBinary() ([]byte, error) {
-	size  := 0
-	count := 1
-	offsetRoom := size
-	{	value := msg.Room
-		size += len(value) }
-	if size  > 0xFFFF { return nil, hopp.ErrPayloadTooLarge}
-	if count > 0xFFFF { return nil, hopp.ErrPayloadTooLarge}
-	buffer := make([]byte, 2 + 4 * count + size)
-	tape.EncodeI16(buffer[:2], uint16(count))
-	{	value := msg.Room
-		tape.EncodeString(buffer[offsetRoom:], value)}
-	return buffer, nil
-}
-
-// UnmarshalBinary dencodes the data from a buffer int this message.
-func (msg *MessageJoin) UnmarshalBinary(buffer []byte) error {
-	pairs, err := tape.DecodePairs(buffer)
-	if err != nil { return err }
-	for tag, data := range pairs {
-		switch tag {
-		case 0:
-			value, err := tape.DecodeString[string](data)
-			if err != nil { return err }
-			msg.Room = value
-		}
-	}
-	return nil
-}
-
-// (513) Chat is sent by the client when it wishes to post a message to the room. It is also relayed by the server to other clients to notify them of the message. It must be sent within a room transaction.
-type MessageChat struct {
-	/* 0 */ Nickname hopp.Option[string]
-	/* 1 */ Content string
-}
-
-// Method returns the method number of the message.
-func (msg MessageChat) Method() uint16 {
-	return 513
-}
-
-// MarshalBinary encodes the data in this message into a buffer.
-func (msg *MessageChat) MarshalBinary() ([]byte, error) {
-	size  := 0
-	count := 1
-	offsetNickname := size
-	if value, ok := msg.Nickname.Get(); ok {
-		count ++
-		size += len(value) }
-	offsetContent := size
-	{	value := msg.Content
-		size += len(value) }
-	if size  > 0xFFFF { return nil, hopp.ErrPayloadTooLarge}
-	if count > 0xFFFF { return nil, hopp.ErrPayloadTooLarge}
-	buffer := make([]byte, 2 + 4 * count + size)
-	tape.EncodeI16(buffer[:2], uint16(count))
-	if value, ok := msg.Nickname.Get(); ok {
-		tape.EncodeString(buffer[offsetNickname:], value)}
-	{	value := msg.Content
-		tape.EncodeString(buffer[offsetContent:], value)}
-	return buffer, nil
-}
-
-// UnmarshalBinary dencodes the data from a buffer int this message.
-func (msg *MessageChat) UnmarshalBinary(buffer []byte) error {
-	pairs, err := tape.DecodePairs(buffer)
-	if err != nil { return err }
-	foundRequired := 0
-	for tag, data := range pairs {
-		switch tag {
-		case 0:
-			value, err := tape.DecodeString[string](data)
-			if err != nil { return err }
-			msg.Nickname = hopp.O(value)
-		case 1:
-			value, err := tape.DecodeString[string](data)
-			if err != nil { return err }
-			msg.Content = value
-			foundRequired ++
-		}
-	}
-	if foundRequired != 1 { return hopp.ErrTablePairMissing }
-	return nil
-}
-
-// (768) JoinNotify is sent by the server when another client joins the room. It must be sent within a room transaction.
-type MessageJoinNotify struct {
-	/* 0 */ Nickname hopp.Option[string]
-}
-
-// Method returns the method number of the message.
-func (msg MessageJoinNotify) Method() uint16 {
-	return 768
-}
-
-// MarshalBinary encodes the data in this message into a buffer.
-func (msg *MessageJoinNotify) MarshalBinary() ([]byte, error) {
-	size  := 0
-	count := 0
-	offsetNickname := size
-	if value, ok := msg.Nickname.Get(); ok {
-		count ++
-		size += len(value) }
-	if size  > 0xFFFF { return nil, hopp.ErrPayloadTooLarge}
-	if count > 0xFFFF { return nil, hopp.ErrPayloadTooLarge}
-	buffer := make([]byte, 2 + 4 * count + size)
-	tape.EncodeI16(buffer[:2], uint16(count))
-	if value, ok := msg.Nickname.Get(); ok {
-		tape.EncodeString(buffer[offsetNickname:], value)}
-	return buffer, nil
-}
-
-// UnmarshalBinary dencodes the data from a buffer int this message.
-func (msg *MessageJoinNotify) UnmarshalBinary(buffer []byte) error {
-	pairs, err := tape.DecodePairs(buffer)
-	if err != nil { return err }
-	foundRequired := 0
-	for tag, data := range pairs {
-		switch tag {
-		case 0:
-			value, err := tape.DecodeString[string](data)
-			if err != nil { return err }
-			msg.Nickname = hopp.O(value)
-		}
-	}
-	if foundRequired != 1 { return hopp.ErrTablePairMissing }
-	return nil
-}
-
-// (769) LeaveNotify is sent by the server when another client leaves the room. It must be sent within a room transaction.
-type MessageLeaveNotify struct {
-	/* 0 */ Nickname hopp.Option[string]
-}
-
-// Method returns the method number of the message.
-func (msg MessageLeaveNotify) Method() uint16 {
-	return 769
-}
-
-// MarshalBinary encodes the data in this message into a buffer.
-func (msg *MessageLeaveNotify) MarshalBinary() ([]byte, error) {
-	size  := 0
-	count := 0
-	offsetNickname := size
-	if value, ok := msg.Nickname.Get(); ok {
-		count ++
-		size += len(value) }
-	if size  > 0xFFFF { return nil, hopp.ErrPayloadTooLarge}
-	if count > 0xFFFF { return nil, hopp.ErrPayloadTooLarge}
-	buffer := make([]byte, 2 + 4 * count + size)
-	tape.EncodeI16(buffer[:2], uint16(count))
-	if value, ok := msg.Nickname.Get(); ok {
-		tape.EncodeString(buffer[offsetNickname:], value)}
-	return buffer, nil
-}
-
-// UnmarshalBinary dencodes the data from a buffer int this message.
-func (msg *MessageLeaveNotify) UnmarshalBinary(buffer []byte) error {
-	pairs, err := tape.DecodePairs(buffer)
-	if err != nil { return err }
-	foundRequired := 0
-	for tag, data := range pairs {
-		switch tag {
-		case 0:
-			value, err := tape.DecodeString[string](data)
-			if err != nil { return err }
-			msg.Nickname = hopp.O(value)
-		}
-	}
-	if foundRequired != 1 { return hopp.ErrTablePairMissing }
-	return nil
-}
-

examples/chat/protocol.go

@@ -0,0 +1,758 @@
+package chat
+
+// Code generated by the Holanet PDL compiler. DO NOT EDIT.
+// The source file is located at <path>
+// Please edit that file instead, and re-compile it to this location.
+// HOPP, TAPE, METADAPT, PDL/0 (c) 2025 holanet.xyz
+
+import "fmt"
+import "git.tebibyte.media/sashakoshka/hopp"
+import "git.tebibyte.media/sashakoshka/hopp/tape"
+
+// Table is a KTV table with an undefined schema.
+type Table = map[uint16] any
+
+// Message is any message that can be sent along this protocol.
+type Message interface {
+	tape.Encodable
+	tape.Decodable
+
+	// Method returns the method code of the message.
+	Method() uint16
+}
+
+// Send encodes a message and sends it along a transaction.
+func Send(trans hopp.Trans, message Message) (n int, err error) {
+	writer, err := trans.SendWriter(message.Method())
+	if err != nil { return n, err }
+	defer writer.Close()
+	encoder := tape.NewEncoder(writer)
+	n, err = message.Encode(encoder)
+	if err != nil { return n, err }
+	return n, encoder.Flush()
+}
+
+// canAssign determines if data from the given source tag can be assigned to
+// a Go type represented by destination. It is designed to receive destination
+// values from [generate.Generator.generateCanAssign]. The eventual Go type and
+// the destination tag must come from the same (or hash-equivalent) PDL type.
+func canAssign(destination, source tape.Tag) bool {
+	if destination.Is(source) { return true }
+	if (destination.Is(tape.SBA) || destination.Is(tape.LBA)) &&
+		(source.Is(tape.SBA) || source.Is(tape.LBA)) {
+		return true
+	}
+	return false
+}
+
+// boolInt converts a bool to an integer.
+func boolInt(input bool) int {
+	if input {
+		return 1
+	} else {
+		return 0
+	}
+}
+
+// ensure ucontainer is always imported
+var _ hopp.Option[int]
+
+// ReceivedMessage is a sealed interface representing the value of a
+// message in this package. To determine what kind of message it is,
+// use a type switch like this:
+// 
+//   switch message := message.(type) {
+//   case MessageError:
+//           doSomething()
+//   case MessageSuccess:
+//           doSomething()
+//   case MessageJoin:
+//           doSomething()
+// 
+//   ...
+// 
+//   }
+type ReceivedMessage interface {
+	isReceivedMessage()
+}
+
+// Error is sent by a party when the other party has done something erroneous. The
+// valid error codes are:
+// 
+//   - 0: General, unspecified error 
+// 
+// The description field, if specified, determines a human-readable error to be
+// shown to the user. The sending party must immediately close the transaction
+// after this message is sent.
+type MessageError struct {
+	Code uint16
+	Description hopp.Option[string]
+}
+
+// Method returns the message's method number.
+func(this *MessageError) Method() uint16 { return 0x0000 }
+
+// Encode encodes this message's tag and value.
+func(this *MessageError) Encode(encoder *tape.Encoder) (n int, err error) {
+	tag_1 := tape.KTV.WithCN(0)
+	nn, err := encoder.WriteTag(tag_1)
+	n += nn; if err != nil { return n, err }
+	if 2 > tape.MaxStructureLength {
+		return n, tape.ErrTooLong
+	}
+	nn, err = encoder.WriteUintN(2, tag_1.CN() + 1)
+	n += nn; if err != nil { return n, err }
+	{
+		if value, ok := (*this).Description.Value(); ok {
+			nn, err = encoder.WriteUint16(0x0001)
+			n += nn; if err != nil { return n, err }
+			tag_2 := tape.StringTag(string(value))
+			nn, err = encoder.WriteUint8(uint8(tag_2))
+			n += nn; if err != nil { return n, err }
+			if len(value) > tape.MaxStructureLength {
+				return n, tape.ErrTooLong
+			}
+			if tag_2.Is(tape.LBA) {
+				nn, err = encoder.WriteUintN(uint64(len(value)), tag_2.CN())
+				n += nn; if err != nil { return n, err }
+			}
+			nn, err = encoder.Write([]byte(value))
+			n += nn; if err != nil { return n, err }
+		}
+		nn, err = encoder.WriteUint16(0x0000)
+		n += nn; if err != nil { return n, err }
+		tag_3 := tape.LI.WithCN(1)
+		nn, err = encoder.WriteUint8(uint8(tag_3))
+		n += nn; if err != nil { return n, err }
+		nn, err = encoder.WriteUint16(uint16((*this).Code))
+		n += nn; if err != nil { return n, err }
+	}
+	return n, nil
+}
+
+// Decode decodes this message's tag and value.
+func(this *MessageError) Decode(decoder *tape.Decoder) (n int, err error) {
+	tag, nn, err := decoder.ReadTag()
+	n += nn; if err != nil { return n, err }
+	if !(canAssign(tape.KTV, tag)) {
+		nn, err = tape.Skim(decoder, tag)
+		n += nn; if err != nil { return n, err }
+		return n, nil
+	}
+	nn, err = decodeBranch_1d505103df99c95e6bed0800d0ea881a_MessageError(this, decoder, tag)
+	n += nn; if err != nil { return n, err }
+	return n, nil
+}
+func (this MessageError) isReceivedMessage() { }
+
+// Success is sent by a party when it has successfully completed a task given to it
+// by the other party. The sending party must immediately close the transaction
+// after this message is sent.
+type MessageSuccess struct {
+}
+
+// Method returns the message's method number.
+func(this *MessageSuccess) Method() uint16 { return 0x0001 }
+
+// Encode encodes this message's tag and value.
+func(this *MessageSuccess) Encode(encoder *tape.Encoder) (n int, err error) {
+	tag_4 := tape.KTV.WithCN(0)
+	nn, err := encoder.WriteTag(tag_4)
+	n += nn; if err != nil { return n, err }
+	if 0 > tape.MaxStructureLength {
+		return n, tape.ErrTooLong
+	}
+	nn, err = encoder.WriteUintN(0, tag_4.CN() + 1)
+	n += nn; if err != nil { return n, err }
+	{
+	}
+	return n, nil
+}
+
+// Decode decodes this message's tag and value.
+func(this *MessageSuccess) Decode(decoder *tape.Decoder) (n int, err error) {
+	tag, nn, err := decoder.ReadTag()
+	n += nn; if err != nil { return n, err }
+	if !(canAssign(tape.KTV, tag)) {
+		nn, err = tape.Skim(decoder, tag)
+		n += nn; if err != nil { return n, err }
+		return n, nil
+	}
+	nn, err = decodeBranch_99914b932bd37a50b983c5e7c90ae93b_MessageSuccess(this, decoder, tag)
+	n += nn; if err != nil { return n, err }
+	return n, nil
+}
+func (this MessageSuccess) isReceivedMessage() { }
+
+// Join is sent by the client when it wishes to join a room. It must begin a new
+// transaction, and that transaction will persist while the user is in that room.
+// Messages having to do with the room will be sent along this transaction. To
+// leave the room, the client must close the transaction.
+type MessageJoin struct {
+	Room string
+	Nickname string
+}
+
+// Method returns the message's method number.
+func(this *MessageJoin) Method() uint16 { return 0x0200 }
+
+// Encode encodes this message's tag and value.
+func(this *MessageJoin) Encode(encoder *tape.Encoder) (n int, err error) {
+	tag_5 := tape.KTV.WithCN(0)
+	nn, err := encoder.WriteTag(tag_5)
+	n += nn; if err != nil { return n, err }
+	if 2 > tape.MaxStructureLength {
+		return n, tape.ErrTooLong
+	}
+	nn, err = encoder.WriteUintN(2, tag_5.CN() + 1)
+	n += nn; if err != nil { return n, err }
+	{
+		nn, err = encoder.WriteUint16(0x0000)
+		n += nn; if err != nil { return n, err }
+		tag_6 := tape.StringTag(string((*this).Room))
+		nn, err = encoder.WriteUint8(uint8(tag_6))
+		n += nn; if err != nil { return n, err }
+		if len((*this).Room) > tape.MaxStructureLength {
+			return n, tape.ErrTooLong
+		}
+		if tag_6.Is(tape.LBA) {
+			nn, err = encoder.WriteUintN(uint64(len((*this).Room)), tag_6.CN())
+			n += nn; if err != nil { return n, err }
+		}
+		nn, err = encoder.Write([]byte((*this).Room))
+		n += nn; if err != nil { return n, err }
+		nn, err = encoder.WriteUint16(0x0001)
+		n += nn; if err != nil { return n, err }
+		tag_7 := tape.StringTag(string((*this).Nickname))
+		nn, err = encoder.WriteUint8(uint8(tag_7))
+		n += nn; if err != nil { return n, err }
+		if len((*this).Nickname) > tape.MaxStructureLength {
+			return n, tape.ErrTooLong
+		}
+		if tag_7.Is(tape.LBA) {
+			nn, err = encoder.WriteUintN(uint64(len((*this).Nickname)), tag_7.CN())
+			n += nn; if err != nil { return n, err }
+		}
+		nn, err = encoder.Write([]byte((*this).Nickname))
+		n += nn; if err != nil { return n, err }
+	}
+	return n, nil
+}
+
+// Decode decodes this message's tag and value.
+func(this *MessageJoin) Decode(decoder *tape.Decoder) (n int, err error) {
+	tag, nn, err := decoder.ReadTag()
+	n += nn; if err != nil { return n, err }
+	if !(canAssign(tape.KTV, tag)) {
+		nn, err = tape.Skim(decoder, tag)
+		n += nn; if err != nil { return n, err }
+		return n, nil
+	}
+	nn, err = decodeBranch_2c5f22d9503118676b4c5584211a4a95_MessageJoin(this, decoder, tag)
+	n += nn; if err != nil { return n, err }
+	return n, nil
+}
+func (this MessageJoin) isReceivedMessage() { }
+
+// Chat is sent by the client when it wishes to post a message to the room. It is
+// also relayed by the server to other clients to notify them of the message. It
+// must be sent within a room transaction.
+type MessageChat struct {
+	Content string
+	Nickname string
+}
+
+// Method returns the message's method number.
+func(this *MessageChat) Method() uint16 { return 0x0300 }
+
+// Encode encodes this message's tag and value.
+func(this *MessageChat) Encode(encoder *tape.Encoder) (n int, err error) {
+	tag_8 := tape.KTV.WithCN(0)
+	nn, err := encoder.WriteTag(tag_8)
+	n += nn; if err != nil { return n, err }
+	if 2 > tape.MaxStructureLength {
+		return n, tape.ErrTooLong
+	}
+	nn, err = encoder.WriteUintN(2, tag_8.CN() + 1)
+	n += nn; if err != nil { return n, err }
+	{
+		nn, err = encoder.WriteUint16(0x0000)
+		n += nn; if err != nil { return n, err }
+		tag_9 := tape.StringTag(string((*this).Content))
+		nn, err = encoder.WriteUint8(uint8(tag_9))
+		n += nn; if err != nil { return n, err }
+		if len((*this).Content) > tape.MaxStructureLength {
+			return n, tape.ErrTooLong
+		}
+		if tag_9.Is(tape.LBA) {
+			nn, err = encoder.WriteUintN(uint64(len((*this).Content)), tag_9.CN())
+			n += nn; if err != nil { return n, err }
+		}
+		nn, err = encoder.Write([]byte((*this).Content))
+		n += nn; if err != nil { return n, err }
+		nn, err = encoder.WriteUint16(0x0001)
+		n += nn; if err != nil { return n, err }
+		tag_10 := tape.StringTag(string((*this).Nickname))
+		nn, err = encoder.WriteUint8(uint8(tag_10))
+		n += nn; if err != nil { return n, err }
+		if len((*this).Nickname) > tape.MaxStructureLength {
+			return n, tape.ErrTooLong
+		}
+		if tag_10.Is(tape.LBA) {
+			nn, err = encoder.WriteUintN(uint64(len((*this).Nickname)), tag_10.CN())
+			n += nn; if err != nil { return n, err }
+		}
+		nn, err = encoder.Write([]byte((*this).Nickname))
+		n += nn; if err != nil { return n, err }
+	}
+	return n, nil
+}
+
+// Decode decodes this message's tag and value.
+func(this *MessageChat) Decode(decoder *tape.Decoder) (n int, err error) {
+	tag, nn, err := decoder.ReadTag()
+	n += nn; if err != nil { return n, err }
+	if !(canAssign(tape.KTV, tag)) {
+		nn, err = tape.Skim(decoder, tag)
+		n += nn; if err != nil { return n, err }
+		return n, nil
+	}
+	nn, err = decodeBranch_5c1cf9347bb6d9f41cee64b186392d24_MessageChat(this, decoder, tag)
+	n += nn; if err != nil { return n, err }
+	return n, nil
+}
+func (this MessageChat) isReceivedMessage() { }
+
+// JoinNotify is sent by the server when another client joins the room. It must be
+// sent within a room transaction.
+type MessageJoinNotify struct {
+	Nickname string
+}
+
+// Method returns the message's method number.
+func(this *MessageJoinNotify) Method() uint16 { return 0x0400 }
+
+// Encode encodes this message's tag and value.
+func(this *MessageJoinNotify) Encode(encoder *tape.Encoder) (n int, err error) {
+	tag_11 := tape.KTV.WithCN(0)
+	nn, err := encoder.WriteTag(tag_11)
+	n += nn; if err != nil { return n, err }
+	if 1 > tape.MaxStructureLength {
+		return n, tape.ErrTooLong
+	}
+	nn, err = encoder.WriteUintN(1, tag_11.CN() + 1)
+	n += nn; if err != nil { return n, err }
+	{
+		nn, err = encoder.WriteUint16(0x0000)
+		n += nn; if err != nil { return n, err }
+		tag_12 := tape.StringTag(string((*this).Nickname))
+		nn, err = encoder.WriteUint8(uint8(tag_12))
+		n += nn; if err != nil { return n, err }
+		if len((*this).Nickname) > tape.MaxStructureLength {
+			return n, tape.ErrTooLong
+		}
+		if tag_12.Is(tape.LBA) {
+			nn, err = encoder.WriteUintN(uint64(len((*this).Nickname)), tag_12.CN())
+			n += nn; if err != nil { return n, err }
+		}
+		nn, err = encoder.Write([]byte((*this).Nickname))
+		n += nn; if err != nil { return n, err }
+	}
+	return n, nil
+}
+
+// Decode decodes this message's tag and value.
+func(this *MessageJoinNotify) Decode(decoder *tape.Decoder) (n int, err error) {
+	tag, nn, err := decoder.ReadTag()
+	n += nn; if err != nil { return n, err }
+	if !(canAssign(tape.KTV, tag)) {
+		nn, err = tape.Skim(decoder, tag)
+		n += nn; if err != nil { return n, err }
+		return n, nil
+	}
+	nn, err = decodeBranch_68c536511e6d598462efc482144438e9_MessageJoinNotify(this, decoder, tag)
+	n += nn; if err != nil { return n, err }
+	return n, nil
+}
+func (this MessageJoinNotify) isReceivedMessage() { }
+
+// LeaveNotify is sent by the server when another client leaves the room. It must
+// be sent within a room transaction.
+type MessageLeaveNotify struct {
+	Nickname string
+}
+
+// Method returns the message's method number.
+func(this *MessageLeaveNotify) Method() uint16 { return 0x0401 }
+
+// Encode encodes this message's tag and value.
+func(this *MessageLeaveNotify) Encode(encoder *tape.Encoder) (n int, err error) {
+	tag_13 := tape.KTV.WithCN(0)
+	nn, err := encoder.WriteTag(tag_13)
+	n += nn; if err != nil { return n, err }
+	if 1 > tape.MaxStructureLength {
+		return n, tape.ErrTooLong
+	}
+	nn, err = encoder.WriteUintN(1, tag_13.CN() + 1)
+	n += nn; if err != nil { return n, err }
+	{
+		nn, err = encoder.WriteUint16(0x0000)
+		n += nn; if err != nil { return n, err }
+		tag_14 := tape.StringTag(string((*this).Nickname))
+		nn, err = encoder.WriteUint8(uint8(tag_14))
+		n += nn; if err != nil { return n, err }
+		if len((*this).Nickname) > tape.MaxStructureLength {
+			return n, tape.ErrTooLong
+		}
+		if tag_14.Is(tape.LBA) {
+			nn, err = encoder.WriteUintN(uint64(len((*this).Nickname)), tag_14.CN())
+			n += nn; if err != nil { return n, err }
+		}
+		nn, err = encoder.Write([]byte((*this).Nickname))
+		n += nn; if err != nil { return n, err }
+	}
+	return n, nil
+}
+
+// Decode decodes this message's tag and value.
+func(this *MessageLeaveNotify) Decode(decoder *tape.Decoder) (n int, err error) {
+	tag, nn, err := decoder.ReadTag()
+	n += nn; if err != nil { return n, err }
+	if !(canAssign(tape.KTV, tag)) {
+		nn, err = tape.Skim(decoder, tag)
+		n += nn; if err != nil { return n, err }
+		return n, nil
+	}
+	nn, err = decodeBranch_68c536511e6d598462efc482144438e9_MessageLeaveNotify(this, decoder, tag)
+	n += nn; if err != nil { return n, err }
+	return n, nil
+}
+func (this MessageLeaveNotify) isReceivedMessage() { }
+
+func decodeBranch_1d505103df99c95e6bed0800d0ea881a_MessageError(this *MessageError, decoder *tape.Decoder, tag tape.Tag) (n int, err error) {
+	var nn int
+	var length_15 uint64
+	if length_15 > uint64(tape.MaxStructureLength) {
+		return n, tape.ErrTooLong
+	}
+	length_15, nn, err = decoder.ReadUintN(int(tag.CN()) + 1)
+	n += nn; if err != nil { return n, err }
+	for _ = range length_15 {
+		var fieldKey_16 uint16
+		fieldKey_16, nn, err = decoder.ReadUint16()
+		n += nn; if err != nil { return n, err }
+		var fieldTag_17 tape.Tag
+		fieldTag_17, nn, err = decoder.ReadTag()
+		n += nn; if err != nil { return n, err }
+		switch fieldKey_16 {
+		case 0x0000:
+			if !(canAssign(tape.LI, fieldTag_17)) {
+				tape.Skim(decoder, fieldTag_17)
+				continue
+			}
+			destination_18, nn, err := decoder.ReadUint16()
+			n += nn; if err != nil { return n, err }
+			*(&(this.Code)) = destination_18
+		case 0x0001:
+			if !(canAssign(tape.LBA, fieldTag_17)) {
+				tape.Skim(decoder, fieldTag_17)
+				continue
+			}
+			var destination_19 string
+			var length_20 uint64
+			if fieldTag_17.Is(tape.LBA) {
+				length_20, nn, err = decoder.ReadUintN(int(fieldTag_17.CN()))
+				n += nn; if err != nil { return n, err }
+			} else {
+				length_20 = uint64(fieldTag_17.CN())
+			}
+			if length_20 > uint64(tape.MaxStructureLength) {
+				return n, tape.ErrTooLong
+			}
+			buffer := make([]byte, length_20)
+			nn, err = decoder.Read(buffer)
+			n += nn; if err != nil { return n, err }
+			*(&destination_19) = string(buffer)
+			this.Description = hopp.O(destination_19)
+		default:
+			tape.Skim(decoder, fieldTag_17)
+			continue
+		}
+	}
+	return n, nil
+}
+
+func decodeBranch_99914b932bd37a50b983c5e7c90ae93b_MessageSuccess(this *MessageSuccess, decoder *tape.Decoder, tag tape.Tag) (n int, err error) {
+	var nn int
+	var length_21 uint64
+	if length_21 > uint64(tape.MaxStructureLength) {
+		return n, tape.ErrTooLong
+	}
+	length_21, nn, err = decoder.ReadUintN(int(tag.CN()) + 1)
+	n += nn; if err != nil { return n, err }
+	for _ = range length_21 {
+		var fieldKey_22 uint16
+		fieldKey_22, nn, err = decoder.ReadUint16()
+		n += nn; if err != nil { return n, err }
+		var fieldTag_23 tape.Tag
+		fieldTag_23, nn, err = decoder.ReadTag()
+		n += nn; if err != nil { return n, err }
+		switch fieldKey_22 {
+		default:
+			tape.Skim(decoder, fieldTag_23)
+			continue
+		}
+	}
+	return n, nil
+}
+
+func decodeBranch_2c5f22d9503118676b4c5584211a4a95_MessageJoin(this *MessageJoin, decoder *tape.Decoder, tag tape.Tag) (n int, err error) {
+	var nn int
+	var length_24 uint64
+	if length_24 > uint64(tape.MaxStructureLength) {
+		return n, tape.ErrTooLong
+	}
+	length_24, nn, err = decoder.ReadUintN(int(tag.CN()) + 1)
+	n += nn; if err != nil { return n, err }
+	for _ = range length_24 {
+		var fieldKey_25 uint16
+		fieldKey_25, nn, err = decoder.ReadUint16()
+		n += nn; if err != nil { return n, err }
+		var fieldTag_26 tape.Tag
+		fieldTag_26, nn, err = decoder.ReadTag()
+		n += nn; if err != nil { return n, err }
+		switch fieldKey_25 {
+		case 0x0000:
+			if !(canAssign(tape.LBA, fieldTag_26)) {
+				tape.Skim(decoder, fieldTag_26)
+				continue
+			}
+			var length_27 uint64
+			if fieldTag_26.Is(tape.LBA) {
+				length_27, nn, err = decoder.ReadUintN(int(fieldTag_26.CN()))
+				n += nn; if err != nil { return n, err }
+			} else {
+				length_27 = uint64(fieldTag_26.CN())
+			}
+			if length_27 > uint64(tape.MaxStructureLength) {
+				return n, tape.ErrTooLong
+			}
+			buffer := make([]byte, length_27)
+			nn, err = decoder.Read(buffer)
+			n += nn; if err != nil { return n, err }
+			*(&(this.Room)) = string(buffer)
+		case 0x0001:
+			if !(canAssign(tape.LBA, fieldTag_26)) {
+				tape.Skim(decoder, fieldTag_26)
+				continue
+			}
+			var length_28 uint64
+			if fieldTag_26.Is(tape.LBA) {
+				length_28, nn, err = decoder.ReadUintN(int(fieldTag_26.CN()))
+				n += nn; if err != nil { return n, err }
+			} else {
+				length_28 = uint64(fieldTag_26.CN())
+			}
+			if length_28 > uint64(tape.MaxStructureLength) {
+				return n, tape.ErrTooLong
+			}
+			buffer := make([]byte, length_28)
+			nn, err = decoder.Read(buffer)
+			n += nn; if err != nil { return n, err }
+			*(&(this.Nickname)) = string(buffer)
+		default:
+			tape.Skim(decoder, fieldTag_26)
+			continue
+		}
+	}
+	return n, nil
+}
+
+func decodeBranch_5c1cf9347bb6d9f41cee64b186392d24_MessageChat(this *MessageChat, decoder *tape.Decoder, tag tape.Tag) (n int, err error) {
+	var nn int
+	var length_29 uint64
+	if length_29 > uint64(tape.MaxStructureLength) {
+		return n, tape.ErrTooLong
+	}
+	length_29, nn, err = decoder.ReadUintN(int(tag.CN()) + 1)
+	n += nn; if err != nil { return n, err }
+	for _ = range length_29 {
+		var fieldKey_30 uint16
+		fieldKey_30, nn, err = decoder.ReadUint16()
+		n += nn; if err != nil { return n, err }
+		var fieldTag_31 tape.Tag
+		fieldTag_31, nn, err = decoder.ReadTag()
+		n += nn; if err != nil { return n, err }
+		switch fieldKey_30 {
+		case 0x0000:
+			if !(canAssign(tape.LBA, fieldTag_31)) {
+				tape.Skim(decoder, fieldTag_31)
+				continue
+			}
+			var length_32 uint64
+			if fieldTag_31.Is(tape.LBA) {
+				length_32, nn, err = decoder.ReadUintN(int(fieldTag_31.CN()))
+				n += nn; if err != nil { return n, err }
+			} else {
+				length_32 = uint64(fieldTag_31.CN())
+			}
+			if length_32 > uint64(tape.MaxStructureLength) {
+				return n, tape.ErrTooLong
+			}
+			buffer := make([]byte, length_32)
+			nn, err = decoder.Read(buffer)
+			n += nn; if err != nil { return n, err }
+			*(&(this.Content)) = string(buffer)
+		case 0x0001:
+			if !(canAssign(tape.LBA, fieldTag_31)) {
+				tape.Skim(decoder, fieldTag_31)
+				continue
+			}
+			var length_33 uint64
+			if fieldTag_31.Is(tape.LBA) {
+				length_33, nn, err = decoder.ReadUintN(int(fieldTag_31.CN()))
+				n += nn; if err != nil { return n, err }
+			} else {
+				length_33 = uint64(fieldTag_31.CN())
+			}
+			if length_33 > uint64(tape.MaxStructureLength) {
+				return n, tape.ErrTooLong
+			}
+			buffer := make([]byte, length_33)
+			nn, err = decoder.Read(buffer)
+			n += nn; if err != nil { return n, err }
+			*(&(this.Nickname)) = string(buffer)
+		default:
+			tape.Skim(decoder, fieldTag_31)
+			continue
+		}
+	}
+	return n, nil
+}
+
+func decodeBranch_68c536511e6d598462efc482144438e9_MessageJoinNotify(this *MessageJoinNotify, decoder *tape.Decoder, tag tape.Tag) (n int, err error) {
+	var nn int
+	var length_34 uint64
+	if length_34 > uint64(tape.MaxStructureLength) {
+		return n, tape.ErrTooLong
+	}
+	length_34, nn, err = decoder.ReadUintN(int(tag.CN()) + 1)
+	n += nn; if err != nil { return n, err }
+	for _ = range length_34 {
+		var fieldKey_35 uint16
+		fieldKey_35, nn, err = decoder.ReadUint16()
+		n += nn; if err != nil { return n, err }
+		var fieldTag_36 tape.Tag
+		fieldTag_36, nn, err = decoder.ReadTag()
+		n += nn; if err != nil { return n, err }
+		switch fieldKey_35 {
+		case 0x0000:
+			if !(canAssign(tape.LBA, fieldTag_36)) {
+				tape.Skim(decoder, fieldTag_36)
+				continue
+			}
+			var length_37 uint64
+			if fieldTag_36.Is(tape.LBA) {
+				length_37, nn, err = decoder.ReadUintN(int(fieldTag_36.CN()))
+				n += nn; if err != nil { return n, err }
+			} else {
+				length_37 = uint64(fieldTag_36.CN())
+			}
+			if length_37 > uint64(tape.MaxStructureLength) {
+				return n, tape.ErrTooLong
+			}
+			buffer := make([]byte, length_37)
+			nn, err = decoder.Read(buffer)
+			n += nn; if err != nil { return n, err }
+			*(&(this.Nickname)) = string(buffer)
+		default:
+			tape.Skim(decoder, fieldTag_36)
+			continue
+		}
+	}
+	return n, nil
+}
+
+func decodeBranch_68c536511e6d598462efc482144438e9_MessageLeaveNotify(this *MessageLeaveNotify, decoder *tape.Decoder, tag tape.Tag) (n int, err error) {
+	var nn int
+	var length_38 uint64
+	if length_38 > uint64(tape.MaxStructureLength) {
+		return n, tape.ErrTooLong
+	}
+	length_38, nn, err = decoder.ReadUintN(int(tag.CN()) + 1)
+	n += nn; if err != nil { return n, err }
+	for _ = range length_38 {
+		var fieldKey_39 uint16
+		fieldKey_39, nn, err = decoder.ReadUint16()
+		n += nn; if err != nil { return n, err }
+		var fieldTag_40 tape.Tag
+		fieldTag_40, nn, err = decoder.ReadTag()
+		n += nn; if err != nil { return n, err }
+		switch fieldKey_39 {
+		case 0x0000:
+			if !(canAssign(tape.LBA, fieldTag_40)) {
+				tape.Skim(decoder, fieldTag_40)
+				continue
+			}
+			var length_41 uint64
+			if fieldTag_40.Is(tape.LBA) {
+				length_41, nn, err = decoder.ReadUintN(int(fieldTag_40.CN()))
+				n += nn; if err != nil { return n, err }
+			} else {
+				length_41 = uint64(fieldTag_40.CN())
+			}
+			if length_41 > uint64(tape.MaxStructureLength) {
+				return n, tape.ErrTooLong
+			}
+			buffer := make([]byte, length_41)
+			nn, err = decoder.Read(buffer)
+			n += nn; if err != nil { return n, err }
+			*(&(this.Nickname)) = string(buffer)
+		default:
+			tape.Skim(decoder, fieldTag_40)
+			continue
+		}
+	}
+	return n, nil
+}
+
+// Receive decodes a message from a transaction and returns it as a value.
+// Use a type switch to determine what type of message it is.
+func Receive(trans hopp.Trans) (message ReceivedMessage, n int, err error) {
+	method, reader, err := trans.ReceiveReader()
+	if err != nil { return nil, n, err }
+	decoder := tape.NewDecoder(reader)
+	switch method {
+	case 0x0000:
+		var message MessageError
+		nn, err := message.Decode(decoder)
+		n += nn; if err != nil { return nil, n, err }
+		return message, n, nil
+	case 0x0001:
+		var message MessageSuccess
+		nn, err := message.Decode(decoder)
+		n += nn; if err != nil { return nil, n, err }
+		return message, n, nil
+	case 0x0200:
+		var message MessageJoin
+		nn, err := message.Decode(decoder)
+		n += nn; if err != nil { return nil, n, err }
+		return message, n, nil
+	case 0x0300:
+		var message MessageChat
+		nn, err := message.Decode(decoder)
+		n += nn; if err != nil { return nil, n, err }
+		return message, n, nil
+	case 0x0400:
+		var message MessageJoinNotify
+		nn, err := message.Decode(decoder)
+		n += nn; if err != nil { return nil, n, err }
+		return message, n, nil
+	case 0x0401:
+		var message MessageLeaveNotify
+		nn, err := message.Decode(decoder)
+		n += nn; if err != nil { return nil, n, err }
+		return message, n, nil
+	}
+	return nil, n, fmt.Errorf("%w: M%04X", hopp.ErrUnknownMethod, method)
+}

examples/chat/protocol.md

@@ -1,70 +0,0 @@
-# Chat Protocol
-
-This document describes a simple chat protocol. To re-generate the source files,
-run `go run ./cmd/hopp-generate examples/chat/protocol.md examples/chat/protocol`
-
-## Messages
-
-### 0000 Error
-| Tag | Name        | Type   | Required |
-| --: | ----------- | ------ | -------- |
-|   0 | Code        | U16    | Yes      |
-|   1 | Description | String | No       |
-
-Error is sent by a party when the other party has done something erroneous. The
-valid error codes are:
-
-- 0: General, unspecified error 
-
-The description field, if specified, determines a human-readable error to be
-shown to the user. The sending party must immediately close the transaction
-after this message is sent.
-
-### 0001 Success
-Success is sent by a party when it has successfully completed a task given to it
-by the other party. The sending party must immediately close the transaction
-after this message is sent.
-
-### 0100 UpdateProfile
-| Tag | Name     | Type   | Required |
-| --: | -------- | ------ | -------- |
-|   0 | Nickname | String | No       |
-
-UpdateProfile is sent by the client in a new transaction to update the profile
-details that will be shown to other connected clients.
-
-### 0200 Join
-| Tag | Name     | Type   | Required |
-| --: | -------- | ------ | -------- |
-|   0 | Room     | String | Yes      |
-
-Join is sent by the client when it wishes to join a room. It must begin a new
-transaction, and that transaction will persist while the user is in that room.
-Messages having to do with the room will be sent along this transaction. To
-leave the room, the client must close the transaction.
-
-### 0201 Chat
-| Tag | Name     | Type   | Required |
-| --: | -------- | ------ | -------- |
-|   0 | Nickname | String | No       |
-|   1 | Content  | String | Yes      |
-
-Chat is sent by the client when it wishes to post a message to the room. It is
-also relayed by the server to other clients to notify them of the message. It
-must be sent within a room transaction.
-
-### 0300 JoinNotify
-| Tag | Name     | Type   | Required |
-| --: | -------- | ------ | -------- |
-|   0 | Nickname | String | No       |
-
-JoinNotify is sent by the server when another client joins the room. It must be
-sent within a room transaction.
-
-### 0301 LeaveNotify
-| Tag | Name     | Type   | Required |
-| --: | -------- | ------ | -------- |
-|   0 | Nickname | String | No       |
-
-LeaveNotify is sent by the server when another client leaves the room. It must
-be sent within a room transaction.

examples/chat/protocol.pdl

@@ -0,0 +1,48 @@
+// Error is sent by a party when the other party has done something erroneous. The
+// valid error codes are:
+// 
+//   - 0: General, unspecified error 
+// 
+// The description field, if specified, determines a human-readable error to be
+// shown to the user. The sending party must immediately close the transaction
+// after this message is sent.
+M0000 Error {
+	0000 Code        U16,
+	0001 Description ?String,
+}
+
+// Success is sent by a party when it has successfully completed a task given to it
+// by the other party. The sending party must immediately close the transaction
+// after this message is sent.
+M0001 Success {
+	
+}
+
+// Join is sent by the client when it wishes to join a room. It must begin a new
+// transaction, and that transaction will persist while the user is in that room.
+// Messages having to do with the room will be sent along this transaction. To
+// leave the room, the client must close the transaction.
+M0200 Join {
+	0000 Room     String,
+	0001 Nickname String,
+}
+
+// Chat is sent by the client when it wishes to post a message to the room. It is
+// also relayed by the server to other clients to notify them of the message. It
+// must be sent within a room transaction.
+M0300 Chat {
+	0000 Content  String,
+	0001 Nickname String,
+}
+
+// JoinNotify is sent by the server when another client joins the room. It must be
+// sent within a room transaction.
+M0400 JoinNotify {
+	0000 Nickname String,
+}
+
+// LeaveNotify is sent by the server when another client leaves the room. It must
+// be sent within a room transaction.
+M0401 LeaveNotify {
+	0000 Nickname String,
+}

examples/chat/server/main.go

@@ -1,6 +1,7 @@
 package main
 
 import "os"
+import "io"
 import "fmt"
 import "log"
 import "errors"
@@ -28,7 +29,7 @@ func main() {
 func host(address string, certPath, keyPath string) error {
 	keyPair, err := tls.LoadX509KeyPair(certPath, keyPath)
 	if err != nil { return err }
-	listener, err := hopp.ListenQUIC("quic", address, &tls.Config {
+	listener, err := hopp.Listen("tls", address, &tls.Config {
 		InsecureSkipVerify: true,
 		Certificates: []tls.Certificate { keyPair },
 	})
@@ -48,7 +49,7 @@ func host(address string, certPath, keyPath string) error {
 
 type client struct {
 	conn     hopp.Conn
-	nickname hopp.Option[string]
+	nickname string
 	rooms    usync.RWMonitor[map[string] hopp.Trans]
 }
 
@@ -58,11 +59,12 @@ func (this *client) run() {
 	defer this.conn.Close()
 
 	for {
-		log.Println("accepting transaction")
 		trans, err := this.conn.AcceptTrans()
-		log.Println("accepted transaction")
 		if err != nil {
-			log.Printf("XXX %v failed: %v", this.conn.RemoteAddr(), err)
+			if !errors.Is(err, io.EOF) {
+				log.Printf("XXX %v failed: %v", this.conn.RemoteAddr(), err)
+			}
+			return
 		}
 		go this.runTrans(trans)
 	}
@@ -70,7 +72,7 @@ func (this *client) run() {
 
 func (this *client) runTrans(trans hopp.Trans) {
 	defer trans.Close()
-	message, err := chat.Receive(trans)
+	message, _, err := chat.Receive(trans)
 	if err != nil {
 		log.Printf(
 			"XXX %v transaction failed: %v",
@@ -96,21 +98,28 @@ func (this *client) transTalk(trans hopp.Trans, initial *chat.MessageJoin) error
 	err := this.joinRoom(trans, room)
 	if err != nil { return err }
 	defer this.leaveRoom(trans, room)
+
+	_, err = chat.Send(trans, &chat.MessageChat {
+		Content: "(i) joined " + room,
+		Nickname: "SYSTEM",
+	})
+	if err != nil { return err }
+	
 	for {
-		message, err := chat.Receive(trans)
+		message, _, err := chat.Receive(trans)
 		if err != nil { return err }
 		switch message := message.(type) {
-		case *chat.MessageChat:
+		case chat.MessageChat:
 			err := this.handleMessageChat(trans, room, message)
 			if err != nil { return err }
-		case *chat.MessageError:
-			return message
+		case chat.MessageError:
+			return &message
 		}
 	}
 }
 
-func (this *client) handleMessageChat(trans hopp.Trans, room string, message *chat.MessageChat) error {
-	log.Println("(). %s #%s: %s", this.nickname.Default("Anonymous"), room, message.Content)
+func (this *client) handleMessageChat(trans hopp.Trans, room string, message chat.MessageChat) error {
+	log.Printf("(). %s #%s: %s", this.nickname, room, message.Content)
 	clients, done := clients.RBorrow()
 	defer done()
 	for client := range clients {
@@ -122,11 +131,11 @@ func (this *client) handleMessageChat(trans hopp.Trans, room string, message *ch
 	return nil
 }
 
-func (this *client) relayMessage(room string, message *chat.MessageChat) error {
+func (this *client) relayMessage(room string, message chat.MessageChat) error {
 	rooms, done := this.rooms.RBorrow()
 	defer done()
 	if trans, ok := rooms[room]; ok {
-		err := chat.Send(trans, message)
+		_, err := chat.Send(trans, &message)
 		if err != nil {
 			return fmt.Errorf("could not relay message: %w", err)
 		}
@@ -141,7 +150,7 @@ func (this *client) joinRoom(trans hopp.Trans, room string) error {
 		return fmt.Errorf("already joined %s", room)
 	}
 	rooms[room] = trans
-	log.Printf("--> user %s joined #%s", this.nickname.Default("Anonymous"), room)
+	log.Printf("--> user %s joined #%s", this.nickname, room)
 	return nil
 }
 
@@ -152,7 +161,7 @@ func (this *client) leaveRoom(trans hopp.Trans, room string) error {
 		return fmt.Errorf("not in %s", room)
 	}
 	delete(rooms, room)
-	log.Printf("<-- user %s left #%s", this.nickname.Default("Anonymous"), room)
+	log.Printf("<-- user %s left #%s", this.nickname, room)
 	return nil
 }
 

examples/min/client/main.go

@@ -0,0 +1,84 @@
+package main
+
+import "io"
+import "os"
+import "log"
+import "fmt"
+import "time"
+import "context"
+import "git.tebibyte.media/sashakoshka/hopp"
+// import "git.tebibyte.media/sashakoshka/hopp/examples/ping"
+
+func main() {
+	name := os.Args[0]
+	if len(os.Args) != 2 {
+		fmt.Fprintf(os.Stderr, "Usage: %s HOST:PORT\n", name)
+		os.Exit(2)
+	}
+	address := os.Args[1]
+	
+	conn, err := dial(address)
+	handleErr(1, err)
+	trans, err := conn.OpenTrans()
+	handleErr(1, err)
+
+	go func() {
+		defer fmt.Fprintf(os.Stdout, "(i) disconnected\n")
+		for {
+			// message, _, err := ping.Receive(trans)
+			// if err != nil {
+			// 	if !errors.Is(err, io.EOF) {
+			// 		handleErr(1, err)
+			// 	}
+			// 	break
+			// }
+			// switch message := message.(type) {
+			// case *ping.MessagePong:
+			// 	log.Printf("--> pong (%d) from %v", message, address)
+			// }
+			method, reader, err := trans.ReceiveReader()
+			if err != nil {
+				log.Printf("CLIENT recv: %v", err)
+				return
+			}
+			data, err := io.ReadAll(reader)
+			if err != nil {
+				log.Printf("CLIENT recv: %v", err)
+				return
+			}
+			log.Println("CLIENT got", method, data)
+		}
+	}()
+	
+	// message := ping.MessagePing(0)
+	// for {
+	// 	log.Printf("<-- ping (%d)", message)
+	// 	_, err := ping.Send(trans, &message)
+	// 	handleErr(1, err)
+	// 	message ++
+	// 	time.Sleep(time.Second)
+	// }
+	data := [1]byte { }
+	for {
+		log.Println("CLIENT send", 1, data)
+		err := trans.Send(1, data[:])
+		handleErr(1, err)
+		data[0] ++
+		time.Sleep(time.Second)
+	}
+}
+
+func dial(address string) (hopp.Conn, error) {
+	ctx, done := context.WithTimeout(context.Background(), 16 * time.Second)
+	defer done()
+	conn, err := hopp.Dial(ctx, "tcp", address, nil)
+	if err != nil { return nil, err }
+	return conn, nil
+}
+
+func handleErr(code int, err error) {
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%s: %v\n", os.Args[0], err)
+		os.Exit(code)
+	}
+}

examples/min/server/main.go

@@ -0,0 +1,97 @@
+package main
+
+import "io"
+import "os"
+import "fmt"
+import "log"
+import "errors"
+import "git.tebibyte.media/sashakoshka/hopp"
+// import "git.tebibyte.media/sashakoshka/hopp/examples/ping"
+
+var network = "tcp"
+var addr    = "localhost:7959"
+
+func main() {
+	name := os.Args[0]
+	if len(os.Args) != 2 {
+		fmt.Fprintf(os.Stderr, "Usage: %s HOST:PORT\n", name)
+		os.Exit(2)
+	}
+	address  := os.Args[1]
+	err := listen(address)
+	handleErr(1, err)
+}
+
+func listen(addr string) error {
+	defer log.Println("(i) closing")
+	
+	listener, err := hopp.Listen(network, addr, nil)
+	if err != nil { return err }
+	log.Printf("(i) hosting on %s", addr)
+	for {
+		conn, err := listener.Accept()
+		if err != nil { return err }
+		go run(conn)
+	}
+}
+
+func run(conn hopp.Conn) {
+	log.Printf("-=E %v connected", conn.RemoteAddr())
+	defer log.Printf("X=- %v disconnected", conn.RemoteAddr())
+	defer conn.Close()
+	
+	for {
+		trans, err := conn.AcceptTrans()
+		if err != nil {
+			if !errors.Is(err, io.EOF) {
+				log.Printf("XXX %v failed: %v", conn.RemoteAddr(), err)
+			}
+			return
+		}
+		go runTrans(conn, trans)
+	}
+}
+
+func runTrans(conn hopp.Conn, trans hopp.Trans) {
+	defer trans.Close()
+
+	for {
+		// message, _, err := ping.Receive(trans)
+		// if err != nil {
+		// 	if !errors.Is(err, io.EOF) {
+		// 		log.Printf("XXX failed to receive message: %v", err)
+		// 	}
+		// 	return
+		// }
+		// switch message := message.(type) {
+		// case *ping.MessagePing:
+		// 	log.Printf("--> ping (%d) from %v", message, conn.RemoteAddr())
+		// 	response := ping.MessagePong(*message)
+		// 	_, err := ping.Send(trans, &response)
+		// 	if err != nil {
+		// 		log.Printf("XXX failed to send message: %v", err)
+		// 		return
+		// 	}
+		// }
+		method, reader, err := trans.ReceiveReader()
+		if err != nil { log.Println("SERVER", err); return }
+		data, err := io.ReadAll(reader)
+		if err != nil { log.Println("SERVER", err); return }
+		log.Println("SERVER got", method, data)
+		log.Println("SERVER send", method, data)
+		func (){
+			writer, err := trans.SendWriter(1)
+			if err != nil { log.Println("SERVER", err); return }
+			defer writer.Close()
+			_, err = writer.Write(data[:])
+			if err != nil { log.Println("SERVER", err); return }
+		}()
+	}
+}
+
+func handleErr(code int, err error) {
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%s: %v\n", os.Args[0], err)
+		os.Exit(code)
+	}
+}

examples/ping/client/main.go

@@ -0,0 +1,65 @@
+package main
+
+import "os"
+import "io"
+import "fmt"
+import "log"
+import "time"
+import "errors"
+import "context"
+import "git.tebibyte.media/sashakoshka/hopp"
+import "git.tebibyte.media/sashakoshka/hopp/examples/ping"
+
+func main() {
+	name := os.Args[0]
+	if len(os.Args) != 2 {
+		fmt.Fprintf(os.Stderr, "Usage: %s HOST:PORT\n", name)
+		os.Exit(2)
+	}
+	address := os.Args[1]
+	
+	conn, err := dial(address)
+	handleErr(1, err)
+	trans, err := conn.OpenTrans()
+	handleErr(1, err)
+
+	go func() {
+		message := ping.MessagePing(0)
+		for _ = range time.Tick(time.Second) {
+			log.Printf("<-- ping (%d)", message)
+			_, err := ping.Send(trans, &message)
+			handleErr(1, err)
+			message ++
+		}
+	}()
+
+	defer fmt.Fprintf(os.Stdout, "(i) disconnected\n")
+	for {
+		message, _, err := ping.Receive(trans)
+		if err != nil {
+			if !errors.Is(err, io.EOF) {
+				handleErr(1, err)
+			}
+			break
+		}
+		switch message := message.(type) {
+		case ping.MessagePong:
+			log.Printf("--> pong (%d) from %v", message, address)
+		}
+	}
+}
+
+func dial(address string) (hopp.Conn, error) {
+	ctx, done := context.WithTimeout(context.Background(), 16 * time.Second)
+	defer done()
+	conn, err := hopp.Dial(ctx, "tcp", address, nil)
+	if err != nil { return nil, err }
+	return conn, nil
+}
+
+func handleErr(code int, err error) {
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%s: %v\n", os.Args[0], err)
+		os.Exit(code)
+	}
+}

examples/ping/doc.go

@@ -0,0 +1,6 @@
+// Example ping demonstrates a simple ping/pong protocol.
+package ping
+
+// To use this in your own project, replace "go run ../../cmd/hopp-generate"
+// with just "hopp-generate".
+//go:generate go run ../../cmd/hopp-generate protocol.pdl -o protocol.go

examples/ping/protocol.go

@@ -0,0 +1,159 @@
+package ping
+
+// Code generated by the Holanet PDL compiler. DO NOT EDIT.
+// The source file is located at <path>
+// Please edit that file instead, and re-compile it to this location.
+// HOPP, TAPE, METADAPT, PDL/0 (c) 2025 holanet.xyz
+
+import "fmt"
+import "git.tebibyte.media/sashakoshka/hopp"
+import "git.tebibyte.media/sashakoshka/hopp/tape"
+
+// Table is a KTV table with an undefined schema.
+type Table = map[uint16] any
+
+// Message is any message that can be sent along this protocol.
+type Message interface {
+	tape.Encodable
+	tape.Decodable
+
+	// Method returns the method code of the message.
+	Method() uint16
+}
+
+// Send encodes a message and sends it along a transaction.
+func Send(trans hopp.Trans, message Message) (n int, err error) {
+	writer, err := trans.SendWriter(message.Method())
+	if err != nil { return n, err }
+	defer writer.Close()
+	encoder := tape.NewEncoder(writer)
+	n, err = message.Encode(encoder)
+	if err != nil { return n, err }
+	return n, encoder.Flush()
+}
+
+// canAssign determines if data from the given source tag can be assigned to
+// a Go type represented by destination. It is designed to receive destination
+// values from [generate.Generator.generateCanAssign]. The eventual Go type and
+// the destination tag must come from the same (or hash-equivalent) PDL type.
+func canAssign(destination, source tape.Tag) bool {
+	if destination.Is(source) { return true }
+	if (destination.Is(tape.SBA) || destination.Is(tape.LBA)) &&
+		(source.Is(tape.SBA) || source.Is(tape.LBA)) {
+		return true
+	}
+	return false
+}
+
+// boolInt converts a bool to an integer.
+func boolInt(input bool) int {
+	if input {
+		return 1
+	} else {
+		return 0
+	}
+}
+
+// ensure ucontainer is always imported
+var _ hopp.Option[int]
+
+// ReceivedMessage is a sealed interface representing the value of a
+// message in this package. To determine what kind of message it is,
+// use a type switch like this:
+// 
+//   switch message := message.(type) {
+//   case MessagePing:
+//           doSomething()
+//   case MessagePong:
+//           doSomething()
+//   }
+type ReceivedMessage interface {
+	isReceivedMessage()
+}
+
+// Ping is sent by the client to the server. It may contain any number. This
+// number will be returned to the client via a [Pong] message.
+type MessagePing int32
+
+// Method returns the message's method number.
+func(this *MessagePing) Method() uint16 { return 0x0000 }
+
+// Encode encodes this message's tag and value.
+func(this *MessagePing) Encode(encoder *tape.Encoder) (n int, err error) {
+	tag_1 := tape.LSI.WithCN(3)
+	nn, err := encoder.WriteTag(tag_1)
+	n += nn; if err != nil { return n, err }
+	nn, err = encoder.WriteInt32(int32((*this)))
+	n += nn; if err != nil { return n, err }
+	return n, nil
+}
+
+// Decode decodes this message's tag and value.
+func(this *MessagePing) Decode(decoder *tape.Decoder) (n int, err error) {
+	tag, nn, err := decoder.ReadTag()
+	n += nn; if err != nil { return n, err }
+	if !(canAssign(tape.LSI, tag)) {
+		nn, err = tape.Skim(decoder, tag)
+		n += nn; if err != nil { return n, err }
+		return n, nil
+	}
+	destination_2, nn, err := decoder.ReadInt32()
+	n += nn; if err != nil { return n, err }
+	*this = MessagePing(destination_2)
+	return n, nil
+}
+func (this MessagePing) isReceivedMessage() { }
+
+// Pong is sent by the server to the client in response to a [Ping] message, It
+// will contain the same number as that message.
+type MessagePong int32
+
+// Method returns the message's method number.
+func(this *MessagePong) Method() uint16 { return 0x0001 }
+
+// Encode encodes this message's tag and value.
+func(this *MessagePong) Encode(encoder *tape.Encoder) (n int, err error) {
+	tag_3 := tape.LSI.WithCN(3)
+	nn, err := encoder.WriteTag(tag_3)
+	n += nn; if err != nil { return n, err }
+	nn, err = encoder.WriteInt32(int32((*this)))
+	n += nn; if err != nil { return n, err }
+	return n, nil
+}
+
+// Decode decodes this message's tag and value.
+func(this *MessagePong) Decode(decoder *tape.Decoder) (n int, err error) {
+	tag, nn, err := decoder.ReadTag()
+	n += nn; if err != nil { return n, err }
+	if !(canAssign(tape.LSI, tag)) {
+		nn, err = tape.Skim(decoder, tag)
+		n += nn; if err != nil { return n, err }
+		return n, nil
+	}
+	destination_4, nn, err := decoder.ReadInt32()
+	n += nn; if err != nil { return n, err }
+	*this = MessagePong(destination_4)
+	return n, nil
+}
+func (this MessagePong) isReceivedMessage() { }
+
+// Receive decodes a message from a transaction and returns it as a value.
+// Use a type switch to determine what type of message it is.
+func Receive(trans hopp.Trans) (message ReceivedMessage, n int, err error) {
+	method, reader, err := trans.ReceiveReader()
+	if err != nil { return nil, n, err }
+	decoder := tape.NewDecoder(reader)
+	switch method {
+	case 0x0000:
+		var message MessagePing
+		nn, err := message.Decode(decoder)
+		n += nn; if err != nil { return nil, n, err }
+		return message, n, nil
+	case 0x0001:
+		var message MessagePong
+		nn, err := message.Decode(decoder)
+		n += nn; if err != nil { return nil, n, err }
+		return message, n, nil
+	}
+	return nil, n, fmt.Errorf("%w: M%04X", hopp.ErrUnknownMethod, method)
+}

examples/ping/protocol.pdl

@@ -0,0 +1,7 @@
+// Ping is sent by the client to the server. It may contain any number. This
+// number will be returned to the client via a [Pong] message.
+M0000 Ping I32
+
+// Pong is sent by the server to the client in response to a [Ping] message, It
+// will contain the same number as that message.
+M0001 Pong I32

examples/ping/server/main.go

@@ -0,0 +1,77 @@
+package main
+
+import "os"
+import "io"
+import "fmt"
+import "log"
+import "errors"
+import "git.tebibyte.media/sashakoshka/hopp"
+import "git.tebibyte.media/sashakoshka/hopp/examples/ping"
+
+func main() {
+	name := os.Args[0]
+	if len(os.Args) != 2 {
+		fmt.Fprintf(os.Stderr, "Usage: %s HOST:PORT\n", name)
+		os.Exit(2)
+	}
+	address  := os.Args[1]
+	err := listen(address)
+	handleErr(1, err)
+}
+
+func listen(address string) error {
+	listener, err := hopp.Listen("tcp", address, nil)
+	if err != nil { return err }
+	log.Printf("(i) hosting on %s", address)
+	for {
+		conn, err := listener.Accept()
+		if err != nil { return err }
+		go run(conn)
+	}
+}
+
+func run(conn hopp.Conn) {
+	log.Printf("-=E %v connected", conn.RemoteAddr())
+	defer log.Printf("X=- %v disconnected", conn.RemoteAddr())
+	defer conn.Close()
+	
+	for {
+		trans, err := conn.AcceptTrans()
+		if err != nil {
+			if !errors.Is(err, io.EOF) {
+				log.Printf("XXX %v failed: %v", conn.RemoteAddr(), err)
+			}
+			return
+		}
+		go runTrans(conn, trans)
+	}
+}
+
+func runTrans(conn hopp.Conn, trans hopp.Trans) {
+	for {
+		message, _, err := ping.Receive(trans)
+		if err != nil {
+			if !errors.Is(err, io.EOF) {
+				log.Printf("XXX failed to receive message: %v", err)
+			}
+			return
+		}
+		switch message := message.(type) {
+		case ping.MessagePing:
+			log.Printf("--> ping (%d) from %v", message, conn.RemoteAddr())
+			response := ping.MessagePong(message)
+			_, err := ping.Send(trans, &response)
+			if err != nil {
+				log.Printf("XXX failed to send message: %v", err)
+				return
+			}
+		}
+	}
+}
+
+func handleErr(code int, err error) {
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%s: %v\n", os.Args[0], err)
+		os.Exit(code)
+	}
+}

generate/generate.go

@@ -11,6 +11,8 @@ import "git.tebibyte.media/sashakoshka/hopp/tape"
 
 const imports =
 `
+import "fmt"
+import "git.tebibyte.media/sashakoshka/hopp"
 import "git.tebibyte.media/sashakoshka/hopp/tape"
 `
 
@@ -19,7 +21,6 @@ const preamble = `
 // The source file is located at <path>
 // Please edit that file instead, and re-compile it to this location.
 // HOPP, TAPE, METADAPT, PDL/0 (c) 2025 holanet.xyz
-
 `
 
 const static = `
@@ -35,6 +36,17 @@ type Message interface {
 	Method() uint16
 }
 
+// Send encodes a message and sends it along a transaction.
+func Send(trans hopp.Trans, message Message) (n int, err error) {
+	writer, err := trans.SendWriter(message.Method())
+	if err != nil { return n, err }
+	defer writer.Close()
+	encoder := tape.NewEncoder(writer)
+	n, err = message.Encode(encoder)
+	if err != nil { return n, err }
+	return n, encoder.Flush()
+}
+
 // canAssign determines if data from the given source tag can be assigned to
 // a Go type represented by destination. It is designed to receive destination
 // values from [generate.Generator.generateCanAssign]. The eventual Go type and
@@ -47,6 +59,18 @@ func canAssign(destination, source tape.Tag) bool {
 	}
 	return false
 }
+
+// boolInt converts a bool to an integer.
+func boolInt(input bool) int {
+	if input {
+		return 1
+	} else {
+		return 0
+	}
+}
+
+// ensure ucontainer is always imported
+var _ hopp.Option[int]
 `
 
 // Generator converts protocols into Go code.
@@ -90,6 +114,8 @@ func (this *Generator) Generate(protocol *Protocol) (n int, err error) {
 	n += nn; if err != nil { return n, err }
 
 	// type definitions
+	nn, err = this.generateMessageValueInterface()
+	n += nn; if err != nil { return n, err }
 	for _, name := range slices.Sorted(maps.Keys(protocol.Types)) {
 		nn, err := this.generateTypedef(name, protocol.Types[name])
 		n += nn; if err != nil { return n, err }
@@ -109,16 +135,63 @@ func (this *Generator) Generate(protocol *Protocol) (n int, err error) {
 		n += nn; if err != nil { return n, err }
 	}
 
+	// receive
+	nn, err = this.generateReceive()
+	n += nn; if err != nil { return n, err }
+
 	return n, nil
 }
 
-func (this *Generator) generateTypedef(name string, typ Type) (n int, err error) {
-	// type definition
-	nn, err := this.iprintf(
-		"\n// %s represents the protocol data type %s.\n",
-		name, name)
+func (this *Generator) generateMessageValueInterface() (n int, err error) {
+	keys := slices.Sorted(maps.Keys(this.protocol.Messages))
+	nn, err := this.iprint(
+		"\n// ReceivedMessage is a sealed interface representing the value of a\n" +
+		"// message in this package. To determine what kind of message it is,\n" +
+		"// use a type switch like this:\n" +
+		"// \n" +
+		"//   switch message := message.(type) {\n")
 	n += nn; if err != nil { return n, err }
-	nn, err = this.iprintf("type %s ", name)
+	for index, method := range keys {
+		if index > 2 {
+			nn, err := this.iprint("// \n//   ...\n// \n")
+			n += nn; if err != nil { return n, err }
+			break
+		}
+		nn, err := this.iprintf("//   case %s:\n",
+			this.resolveMessageName(this.protocol.Messages[method].Name))
+		n += nn; if err != nil { return n, err }
+		nn, err = this.iprintf("//           doSomething()\n")
+		n += nn; if err != nil { return n, err }
+	}
+	nn, err = this.iprintf("//   }\n")
+	n += nn; if err != nil { return n, err }
+	
+	nn, err = this.iprintf("type ReceivedMessage interface {\n")
+	n += nn; if err != nil { return n, err }
+	this.push()
+		nn, err = this.iprintf("isReceivedMessage()\n")
+		n += nn; if err != nil { return n, err }
+	this.pop()
+	nn, err = this.iprintf("}\n")
+	n += nn; if err != nil { return n, err }
+	
+	return n, nil
+}
+
+func (this *Generator) generateTypedef(name string, typedef Typedef) (n int, err error) {
+	typ := typedef.Type
+
+	// type definition
+	if typedef.Doc == "" {
+		nn, err := this.iprintf(
+			"\n// %s represents the protocol data type %s.\n",
+			name, name)
+		n += nn; if err != nil { return n, err }
+	} else {
+		nn, err := this.iprintf("\n%s\n", this.formatComment(typedef.Doc))
+		n += nn; if err != nil { return n, err }
+	}
+	nn, err := this.iprintf("type %s ", name)
 	n += nn; if err != nil { return n, err }
 	nn, err = this.generateType(typ)
 	n += nn; if err != nil { return n, err }
@@ -165,7 +238,7 @@ func (this *Generator) generateTypedef(name string, typ Type) (n int, err error)
 	
 	// DecodeValue method
 	nn, err = this.iprintf(
-		"\n // DecodeValue decodes the value of this type without " +
+		"\n// DecodeValue decodes the value of this type without " +
 		"the tag. The value is\n// decoded according to the " +
 		"parameters specified by the tag, if possible.\n")
 	n += nn; if err != nil { return n, err }
@@ -208,10 +281,16 @@ func (this *Generator) generateTypedef(name string, typ Type) (n int, err error)
 // generateMessage generates the structure, as well as encoding decoding
 // functions for the given message.
 func (this *Generator) generateMessage(method uint16, message Message) (n int, err error) {
-	nn, err := this.iprintf(
-		"\n// %s represents the protocol message M%04X %s.\n",
-		message.Name, method, message.Name)
-	nn, err = this.iprintf("type %s ", this.resolveMessageName(message.Name))
+	if message.Doc == "" {
+		nn, err := this.iprintf(
+			"\n// %s represents the protocol message M%04X %s.\n",
+			message.Name, method, message.Name)
+		n += nn; if err != nil { return n, err }
+	} else {
+		nn, err := this.iprintf("\n%s\n", this.formatComment(message.Doc))
+		n += nn; if err != nil { return n, err }
+	}
+	nn, err := this.iprintf("type %s ", this.resolveMessageName(message.Name))
 	n += nn; if err != nil { return n, err }
 	nn, err = this.generateType(message.Type)
 	n += nn; if err != nil { return n, err }
@@ -286,6 +365,10 @@ func (this *Generator) generateMessage(method uint16, message Message) (n int, e
 	this.pop()
 	nn, err = this.iprintf("}\n")
 	n += nn; if err != nil { return n, err }
+
+	// isReceivedMessage method
+	nn, err = this.iprintf("func (this %s) isReceivedMessage() { }\n", this.resolveMessageName(message.Name))
+	n += nn; if err != nil { return n, err }
 	
 	return n, nil
 }
@@ -302,6 +385,9 @@ func (this *Generator) generateMessage(method uint16, message Message) (n int, e
 //   - nn int
 func (this *Generator) generateEncodeValue(typ Type, valueSource, tagSource string) (n int, err error) {
 	switch typ := typ.(type) {
+	case TypeBool:
+		// SI: (none)
+		// SI stores the value in the tag, so we write nothing here
 	case TypeInt:
 		// SI:     (none)
 		// LI/LSI: <value: IntN>
@@ -454,19 +540,33 @@ func (this *Generator) generateEncodeValue(typ Type, valueSource, tagSource stri
 		n += nn; if err != nil { return n, err }
 		this.push()
 			for key, field := range typ.Fields {
+				fieldSource := fmt.Sprintf("%s.%s", valueSource, field.Name)
+				if field.Option {
+					nn, err = this.iprintf("if value, ok := %s.Value(); ok {\n", fieldSource)
+					n += nn; if err != nil { return n, err }
+					fieldSource = "value"
+					this.push()
+				}
+
 				nn, err = this.iprintf("nn, err = encoder.WriteUint16(0x%04X)\n", key)
 				n += nn; if err != nil { return n, err }
 				nn, err = this.generateErrorCheck()
 				n += nn; if err != nil { return n, err }
-				fieldSource := fmt.Sprintf("%s.%s", valueSource, field.Name)
 				tagVar, nn, err := this.generateTag(field.Type, fieldSource)
 				n += nn; if err != nil { return n, err }
 				nn, err = this.iprintf("nn, err = encoder.WriteUint8(uint8(%s))\n", tagVar)
 				n += nn; if err != nil { return n, err }
 				nn, err = this.generateErrorCheck()
 				n += nn; if err != nil { return n, err }
+				
 				nn, err = this.generateEncodeValue(field.Type, fieldSource, tagVar)
 				n += nn; if err != nil { return n, err }
+				
+				if field.Option {
+					this.pop()
+					nn, err = this.iprintf("}\n")
+					n += nn; if err != nil { return n, err }
+				}
 			}
 		this.pop()
 		nn, err = this.iprintf("}\n")
@@ -505,6 +605,11 @@ func (this *Generator) generateEncodeValue(typ Type, valueSource, tagSource stri
 // for [Generator.generateDecodeBranch].
 func (this *Generator) generateDecodeValue(typ Type, typeName, valueSource, tagSource string) (n int, err error) {
 	switch typ := typ.(type) {
+	case TypeBool:
+		// SI: (none)
+		// SI stores the value in the tag
+		nn, err := this.iprintf("*%s = %s.CN() > 0\n", valueSource, tagSource)
+		n += nn; if err != nil { return n, err }
 	case TypeInt:
 		// SI:     (none)
 		// LI/LSI: <value: IntN>
@@ -524,13 +629,7 @@ func (this *Generator) generateDecodeValue(typ Type, typeName, valueSource, tagS
 			prefix = "ReadInt"
 		}
 		destinationVar := this.newTemporaryVar("destination")
-		nn, err := this.iprintf("var %s ", destinationVar)
-		n += nn; if err != nil { return n, err }
-		nn, err = this.generateType(typ)
-		n += nn; if err != nil { return n, err }
-		nn, err = this.print("\n")
-		n += nn; if err != nil { return n, err }
-		nn, err = this.iprintf("%s, nn, err = decoder.%s%d()\n", destinationVar, prefix, typ.Bits)
+		nn, err := this.iprintf("%s, nn, err := decoder.%s%d()\n", destinationVar, prefix, typ.Bits)
 		n += nn; if err != nil { return n, err }
 		nn, err = this.generateErrorCheck()
 		n += nn; if err != nil { return n, err }
@@ -544,13 +643,7 @@ func (this *Generator) generateDecodeValue(typ Type, typeName, valueSource, tagS
 	case TypeFloat:
 		// FP: <value: FloatN>
 		destinationVar := this.newTemporaryVar("destination")
-		nn, err := this.iprintf("var %s ", destinationVar)
-		n += nn; if err != nil { return n, err }
-		nn, err = this.generateType(typ)
-		n += nn; if err != nil { return n, err }
-		nn, err = this.print("\n")
-		n += nn; if err != nil { return n, err }
-		nn, err = this.iprintf("%s, nn, err = decoder.ReadFloat%d()\n", destinationVar, typ.Bits)
+		nn, err := this.iprintf("%s, nn, err := decoder.ReadFloat%d()\n", destinationVar, typ.Bits)
 		n += nn; if err != nil { return n, err }
 		nn, err = this.generateErrorCheck()
 		n += nn; if err != nil { return n, err }
@@ -773,6 +866,7 @@ func (this *Generator) generateDecodeBranch(hash [16]byte, typ Type, typeName st
 			nn, err = this.iprintf("}\n")
 			n += nn; if err != nil { return n, err }
 		case TypeTableDefined:
+			// TODO: options
 			// KTV: <length: UN> (<key: U16> <tag: Tag> <value>)*
 			// read header
 			lengthVar := this.newTemporaryVar("length")
@@ -849,10 +943,25 @@ func (this *Generator) generateDecodeBranch(hash [16]byte, typ Type, typeName st
 					n += nn; if err != nil { return n, err }
 
 					// decode payload
-					nn, err = this.generateDecodeValue(
-						field.Type, "",
-						fmt.Sprintf("(&(this.%s))", field.Name), fieldTagVar)
-					n += nn; if err != nil { return n, err }
+					if field.Option {
+						destination := this.newTemporaryVar("destination")
+						nn, err = this.iprintf("var %s ", destination)
+						n += nn; if err != nil { return n, err }
+						nn, err = this.generateType(field.Type)
+						n += nn; if err != nil { return n, err }
+						nn, err = this.printf("\n")
+						n += nn; if err != nil { return n, err }
+						nn, err = this.generateDecodeValue(
+							field.Type, "", fmt.Sprintf("(&%s)", destination), fieldTagVar)
+						n += nn; if err != nil { return n, err }
+						nn, err = this.iprintf("this.%s = hopp.O(%s)\n", field.Name, destination)
+						n += nn; if err != nil { return n, err }
+					} else {
+						nn, err = this.generateDecodeValue(
+							field.Type, "",
+							fmt.Sprintf("(&(this.%s))", field.Name), fieldTagVar)
+						n += nn; if err != nil { return n, err }
+					}
 					this.pop()
 				}					
 				nn, err = this.iprintf("default:\n")
@@ -865,16 +974,6 @@ func (this *Generator) generateDecodeBranch(hash [16]byte, typ Type, typeName st
 			this.pop()
 			nn, err = this.iprintf("}\n")
 			n += nn; if err != nil { return n, err }
-			
-			// TODO once options are implemented, have a set of
-			// bools for each non-optional field, and check here
-			// that they are all true. a counter will not work
-			// because if someone specifies a non-optional field
-			// twice, they can neglect to specify another
-			// non-optional field and we won't even know because the
-			// count will still be even. we shouldn't use a map
-			// either because its an allocation and its way more
-			// memory than just, like 5 bools (on the stack no less)
 		default: return n, fmt.Errorf("unexpected type: %T", typ)
 		}
 
@@ -931,6 +1030,9 @@ func (this *Generator) generateBareErrorCheck() (n int, err error) {
 func (this *Generator) generateTag(typ Type, source string) (tagVar string, n int, err error) {
 	tagVar = this.newTemporaryVar("tag")
 	switch typ := typ.(type) {
+	case TypeBool:
+		nn, err := this.iprintf("%s := tape.SI.WithCN(boolInt(bool(%s)))\n", tagVar, source)
+		n += nn; if err != nil { return tagVar, n, err }
 	case TypeInt:
 		if typ.Bits <= 5 {
 			nn, err := this.iprintf("%s := tape.SI.WithCN(int(%s))\n", tagVar, source)
@@ -984,6 +1086,9 @@ func (this *Generator) generateTag(typ Type, source string) (tagVar string, n in
 // information is chosen.
 func (this *Generator) generateTN(typ Type) (n int, err error) {
 	switch typ := typ.(type) {
+	case TypeBool:
+		nn, err := this.printf("tape.SI")
+		n += nn; if err != nil { return n, err }
 	case TypeInt:
 		if typ.Bits <= 5 {
 			nn, err := this.printf("tape.SI")
@@ -1027,6 +1132,9 @@ func (this *Generator) generateTN(typ Type) (n int, err error) {
 
 func (this *Generator) generateType(typ Type) (n int, err error) {
 	switch typ := typ.(type) {
+	case TypeBool:
+		nn, err := this.printf("bool")
+		n += nn; if err != nil { return n, err }
 	case TypeInt:
 		if err := this.validateIntBitSize(typ.Bits); err != nil {
 			return n, err
@@ -1090,10 +1198,22 @@ func (this *Generator) generateTypeTableDefined(typ TypeTableDefined) (n int, er
 
 	for _, key := range slices.Sorted(maps.Keys(typ.Fields)) {
 		field := typ.Fields[key]
-		nn, err := this.iprintf("%s ", field.Name)
+		if field.Doc != "" {
+			nn, err := this.iprintf("%s\n", this.formatComment(field.Doc))
+			n += nn; if err != nil { return n, err }
+		}
+		nn, err = this.iprintf("%s ", field.Name)
 		n += nn; if err != nil { return n, err }
+		if field.Option {
+			nn, err = this.print("hopp.Option[")
+			n += nn; if err != nil { return n, err }
+		}
 		nn, err = this.generateType(field.Type)
 		n += nn; if err != nil { return n, err }
+		if field.Option {
+			nn, err = this.print("]")
+			n += nn; if err != nil { return n, err }
+		}
 		nn, err = this.print("\n")
 		n += nn; if err != nil { return n, err }
 	}
@@ -1122,6 +1242,53 @@ func (this *Generator) generateCanAssign(typ Type, tagSource string) (n int, err
 	return n, nil
 }
 
+// generateReceive generates a function Receive(hopp.Trans) (Message, int, error)
+func (this *Generator) generateReceive() (n int, err error) {
+	nn, err := this.iprintf(
+		"\n// Receive decodes a message from a transaction and returns it as a value.\n" +
+		"// Use a type switch to determine what type of message it is.\n")
+	n += nn; if err != nil { return n, err }
+	nn, err = this.iprintf(
+		"func Receive(trans hopp.Trans) (message ReceivedMessage, n int, err error) {\n")
+	n += nn; if err != nil { return n, err }
+	this.push()
+		nn, err = this.iprintf("method, reader, err := trans.ReceiveReader()\n")
+		n += nn; if err != nil { return n, err }
+		nn, err = this.iprintf("if err != nil { return nil, n, err }\n")
+		n += nn; if err != nil { return n, err }
+		nn, err = this.iprintf("decoder := tape.NewDecoder(reader)\n")
+		n += nn; if err != nil { return n, err }
+		nn, err = this.iprintf("switch method {\n")
+		n += nn; if err != nil { return n, err }
+		for method, message := range this.protocol.Messages {
+			nn, err = this.iprintf("case 0x%04X:\n", method)
+			n += nn; if err != nil { return n, err }
+			this.push()
+				nn, err = this.iprintf(
+					"var message %s\n",
+					this.resolveMessageName(message.Name))
+				n += nn; if err != nil { return n, err }
+				nn, err := this.iprintf(
+					"nn, err := message.Decode(decoder)\n")
+				n += nn; if err != nil { return n, err }
+				nn, err = this.iprintf("n += nn; if err != nil { return nil, n, err }\n")
+				n += nn; if err != nil { return n, err }
+				nn, err = this.iprintf("return message, n, nil\n")
+				n += nn; if err != nil { return n, err }
+			this.pop()
+		}
+		nn, err = this.iprint("}\n")
+		n += nn; if err != nil { return n, err }
+		// fuck off go vet
+		str := `return nil, n, fmt.Errorf("%w: M%04X", hopp.ErrUnknownMethod, method)`
+		nn, err = this.iprintln(str)
+		n += nn; if err != nil { return n, err }
+	this.pop()
+	nn, err = this.iprint("}\n")
+	n += nn; if err != nil { return n, err }
+	return n, nil
+}
+
 func (this *Generator) validateIntBitSize(size int) error {
 	switch size {
 	case 5, 8, 16, 32, 64: return nil
@@ -1175,17 +1342,21 @@ func (this *Generator) iprintf(format string, args ...any) (n int, err error) {
 	return fmt.Fprintf(this.Output, this.indent() + format, args...)
 }
 
+func (this *Generator) formatComment(comment string) string {
+	return "// " + strings.ReplaceAll(comment, "\n", "\n" + this.indent() + "// ")
+}
+
 func (this *Generator) resolveMessageName(message string) string {
 	return "Message" + message
 }
 
 func (this *Generator) resolveTypeName(name string) (Type, error) {	
-	if typ, ok := this.protocol.Types[name]; ok {
-		if typ, ok := typ.(TypeNamed); ok {
+	if typedef, ok := this.protocol.Types[name]; ok {
+		if typ, ok := typedef.Type.(TypeNamed); ok {
 			return this.resolveTypeName(typ.Name)
 		}
 		
-		return typ, nil
+		return typedef.Type, nil
 	}
 	return nil, fmt.Errorf("no type exists called %s", name)
 }

generate/generate_test.go

@@ -7,8 +7,10 @@ import "testing"
 // generator is equal to something specific
 
 var exampleProtocol = defaultProtocol()
+var pingProtocol    = defaultProtocol()
 
 func init() {
+	// example protocol
 	exampleProtocol.Messages[0x0000] = Message {
 		Name: "Connect",
 		Type: TypeTableDefined {
@@ -59,6 +61,7 @@ func init() {
 				0x000C: Field { Name: "NI16",Type: TypeInt { Bits: 16, Signed: true } },
 				0x000D: Field { Name: "NI32",Type: TypeInt { Bits: 32, Signed: true } },
 				0x000E: Field { Name: "NI64",Type: TypeInt { Bits: 64, Signed: true } },
+				0x000F: Field { Name: "Bool",Type: TypeBool { } },
 			},
 		},
 	}
@@ -83,13 +86,53 @@ func init() {
 			},
 		},
 	}
-	exampleProtocol.Types["User"] = TypeTableDefined {
-		Fields: map[uint16] Field {
-			0x0000: Field { Name: "Name",      Type: TypeString { } },
-			0x0001: Field { Name: "Bio",       Type: TypeString { } },
-			0x0002: Field { Name: "Followers", Type: TypeInt { Bits: 32 } },
+	exampleProtocol.Messages[0x0006] = Message {
+		Name: "Option",
+		Type: TypeTableDefined {
+			Fields: map[uint16] Field {
+				0x0000: Field { Name: "OU5",     Option: true, Type: TypeInt    { Bits: 5  } },
+				0x0001: Field { Name: "OU8",     Option: true, Type: TypeInt    { Bits: 8  } },
+				0x0002: Field { Name: "OU16",    Option: true, Type: TypeInt    { Bits: 16 } },
+				0x0003: Field { Name: "OU32",    Option: true, Type: TypeInt    { Bits: 32 } },
+				0x0004: Field { Name: "OU64",    Option: true, Type: TypeInt    { Bits: 64 } },
+				0x0005: Field { Name: "OI8",     Option: true, Type: TypeInt    { Bits: 8,  Signed: true } },
+				0x0006: Field { Name: "OI16",    Option: true, Type: TypeInt    { Bits: 16, Signed: true } },
+				0x0007: Field { Name: "OI32",    Option: true, Type: TypeInt    { Bits: 32, Signed: true } },
+				0x0008: Field { Name: "OI64",    Option: true, Type: TypeInt    { Bits: 64, Signed: true } },
+				0x0009: Field { Name: "OF32",    Option: true, Type: TypeFloat  { Bits: 32 } },
+				0x000A: Field { Name: "OF64",    Option: true, Type: TypeFloat  { Bits: 64 } },
+				0x000B: Field { Name: "OBool",   Option: true, Type: TypeBool   { } },
+				0x000C: Field { Name: "OString", Option: true, Type: TypeString { } },
+				0x000D: Field { Name: "OArray",  Option: true, Type: TypeArray {
+					Element: TypeInt { Bits: 16, Signed: true } } },
+				0x000E: Field { Name: "OTable",  Option: true, Type: TypeTableDefined {
+					Fields: map[uint16] Field {
+						0x0001: Field { Name: "A", Type: TypeInt   { Bits: 8, Signed: true }, },
+						0x0002: Field { Name: "B", Type: TypeFloat { Bits: 64 }, },
+					} } },
+				0x000F: Field { Name: "T0", Option: true, Type: TypeTable { } },
+			},
 		},
 	}
+	exampleProtocol.Types["User"] = Typedef {
+		Type: TypeTableDefined {
+			Fields: map[uint16] Field {
+				0x0000: Field { Name: "Name",      Type: TypeString { } },
+				0x0001: Field { Name: "Bio",       Type: TypeString { } },
+				0x0002: Field { Name: "Followers", Type: TypeInt { Bits: 32 } },
+			},
+		},
+	}
+	
+	// ping protocol
+	pingProtocol.Messages[0x0000] = Message {
+		Name: "Ping",
+		Type: TypeInt { Bits: 32, Signed: true },
+	}
+	pingProtocol.Messages[0x0001] = Message {
+		Name: "Pong",
+		Type: TypeInt { Bits: 32, Signed: true },
+	}
 }
 
 func TestGenerateRunEncodeDecode(test *testing.T) {
@@ -199,10 +242,11 @@ func TestGenerateRunEncodeDecode(test *testing.T) {
 			NI16: -0x34C9,
 			NI32: -0x10E134C9,
 			NI64: -0x639109BC10E134C9,
+			Bool: true,
 		}
 		testEncodeDecode(
 			&messageIntegers,
-			tu.S(0xE0, 13).AddVar(
+			tu.S(0xE0, 14).AddVar(
 				[]byte { 0x00, 0x00, 0x13 },
 				[]byte { 0x00, 0x01, 0x20, 0xC9 },
 				[]byte { 0x00, 0x02, 0x21, 0x34, 0xC9 },
@@ -216,6 +260,7 @@ func TestGenerateRunEncodeDecode(test *testing.T) {
 				[]byte { 0x00, 0x0C, 0x41, 0xCB, 0x37 },
 				[]byte { 0x00, 0x0D, 0x43, 0xEF, 0x1E, 0xCB, 0x37 },
 				[]byte { 0x00, 0x0E, 0x47, 0x9C, 0x6E, 0xF6, 0x43, 0xEF, 0x1E, 0xCB, 0x37 },
+				[]byte { 0x00, 0x0F, 0x01 },
 				))
 		log.Println("MessageDynamic")
 		messageDynamic := MessageDynamic {
@@ -243,31 +288,32 @@ func TestGenerateRunEncodeDecode(test *testing.T) {
 		}
 		testEncodeDecode(
 			&messageDynamic,
-			tu.S(0xE0, 14).AddVar(
-				[]byte { 0x00, 0x00, 0x20, 0x23 },
-				[]byte { 0x00, 0x01, 0x21, 0x32, 0x47 },
-				[]byte { 0x00, 0x02, 0x23, 0x87, 0x32, 0x45, 0x23 },
-				[]byte { 0x00, 0x03, 0x27, 0x32, 0x84, 0x02, 0x90, 0x34, 0x09, 0x82, 0x34 },
-				[]byte { 0x00, 0x04, 0x40, 0x23 },
-				[]byte { 0x00, 0x05, 0x41, 0x32, 0x47 },
-				[]byte { 0x00, 0x06, 0x43, 0x57, 0x32, 0x45, 0x23 },
-				[]byte { 0x00, 0x07, 0x47, 0x32, 0x84, 0x02, 0x90, 0x34, 0x09, 0x82, 0x34 },
-				[]byte { 0x00, 0x08, 0x63, 0x45, 0x12, 0x63, 0xCE },
-				[]byte { 0x00, 0x09, 0x67, 0x40, 0x74, 0x4E, 0x3D, 0x6F, 0xCD, 0x17, 0x75 },
-				[]byte { 0x00, 0x0A, 0x87, 'f', 'o', 'x', ' ', 'b', 'e', 'd' },
-				[]byte { 0x00, 0x0B, 0xC0, 0x04, 0x41,
+			snake.O().AddL(0xE0, 14).AddS(
+				snake.L(0x00, 0x00, 0x20, 0x23),
+				snake.L(0x00, 0x01, 0x21, 0x32, 0x47),
+				snake.L(0x00, 0x02, 0x23, 0x87, 0x32, 0x45, 0x23),
+				snake.L(0x00, 0x03, 0x27, 0x32, 0x84, 0x02, 0x90, 0x34, 0x09, 0x82, 0x34),
+				snake.L(0x00, 0x04, 0x40, 0x23),
+				snake.L(0x00, 0x05, 0x41, 0x32, 0x47),
+				snake.L(0x00, 0x06, 0x43, 0x57, 0x32, 0x45, 0x23),
+				snake.L(0x00, 0x07, 0x47, 0x32, 0x84, 0x02, 0x90, 0x34, 0x09, 0x82, 0x34),
+				snake.L(0x00, 0x08, 0x63, 0x45, 0x12, 0x63, 0xCE),
+				snake.L(0x00, 0x09, 0x67, 0x40, 0x74, 0x4E, 0x3D, 0x6F, 0xCD, 0x17, 0x75),
+				snake.L(0x00, 0x0A, 0x87, 'f', 'o', 'x', ' ', 'b', 'e', 'd'),
+				snake.L(0x00, 0x0B, 0xC0, 0x04, 0x41,
 					0x00, 0x07,
 					0x00, 0x06,
 					0x00, 0x05,
-					0x00, 0x04 },
-				[]byte { 0x00, 0x0C, 0xE0, 0x02,
+					0x00, 0x04),
+				snake.L(0x00, 0x0C, 0xE0, 0x02,
 					0x00, 0x01, 0x40, 0x08,
-					0x00, 0x02, 0x67, 0x40, 0x11, 0x99, 0x99, 0x99, 0x99, 0x99, 0x9A },
-				[]byte { 0x00, 0x0D, 0xE0, 0x03, // ERR
-					0x00, 0x01, 0x63, 0x43, 0xF4, 0xC0, 0x00,
-					0x00, 0x02, 0x82, 'h', 'i',
-					0x00, 0x03, 0x21, 0x39, 0x92 },
-				))
+					0x00, 0x02, 0x67, 0x40, 0x11, 0x99, 0x99, 0x99, 0x99, 0x99, 0x9A),
+				snake.O(snake.L(0x00, 0x0D, 0xE0, 0x03),
+					snake.S(
+						snake.L(0x00, 0x01, 0x63, 0x43, 0xF4, 0xC0, 0x00),
+						snake.L(0x00, 0x02, 0x82, 'h', 'i'),
+						snake.L(0x00, 0x03, 0x21, 0x39, 0x92)),
+				)))
 	`)
 }
 
@@ -451,3 +497,119 @@ func TestGenerateRunDecodeWrongType(test *testing.T) {
 		}
 	`)
 }
+
+func TestGenerateRunSendReceive(test *testing.T) {
+	testGenerateRun(test, &pingProtocol, "send-receive", `
+		// imports
+		import "git.tebibyte.media/sashakoshka/hopp/internal/mock"
+	`, `
+		log.Println("Send"); {
+			message := MessagePing(77)
+			trans   := mock.Trans { }
+			_, err := Send(&trans, &message)
+			if err != nil { log.Fatal(err) }
+			gotMethod, gotPayload := trans.Methods[0], trans.Messages[0]
+			log.Printf("method M%04X", gotMethod)
+			log.Println("payload", tu.HexBytes(gotPayload))
+			if gotMethod != 0x0000 {
+				log.Fatalln("wrong method")
+			}
+			if ok, n := snake.L(0x43, 0x00, 0x00, 0x00, 0x4D).Check(gotPayload); !ok {
+				log.Fatalln("not equal at:", n)
+			}
+		}
+
+		log.Println("Receive"); {
+			trans := mock.Trans {
+				Methods:  []uint16 { 1 },
+				Messages: [][]byte { []byte { 0x43, 0x00, 0x00, 0x00, 0x4E } },
+			}
+			gotMessage, n, err := Receive(&trans)
+			if err != nil { log.Fatal(err) }
+			log.Println("message", gotMessage)
+			log.Println("n",       n)
+			casted, ok := gotMessage.(MessagePong)
+			if !ok          { log.Fatalln("expected MessagePong") }
+			if casted != 78 { log.Fatalln("wrong message value") }
+			if n != 5       { log.Fatalln("wrong n value") }
+		}
+	`)
+}
+
+func TestGenerateRunConn(test *testing.T) {
+	testGenerateRun(test, &pingProtocol, "send-receive", `
+		// imports
+		import "sync"
+		import "context"
+		import "git.tebibyte.media/sashakoshka/hopp"
+	`, `
+		group := sync.WaitGroup { }
+		group.Add(2)
+	
+		// server
+		listener, err := hopp.Listen("tcp", "localhost:43957", nil)
+		if err != nil { log.Fatalln("SERVER listen:", err) }
+		go func() {
+			defer listener.Close()
+			defer group.Done()
+			
+			conn, err := listener.Accept()
+			if err != nil { log.Fatalln("SERVER accept:", err) }
+			trans, err := conn.AcceptTrans()
+			if err != nil { log.Fatalln("SERVER accept trans:", err) }
+			
+			message, n, err := Receive(trans)
+			if err != nil { log.Fatalln("SERVER receive:", err) }
+			log.Println("SERVER got message", message)
+			log.Println("SERVER got n",       n)
+			casted, ok := message.(MessagePing)
+			if !ok          { log.Fatalln("SERVER expected MessagePong") }
+			if casted != 77 { log.Fatalln("SERVER wrong message value") }
+			if n != 5       { log.Fatalln("SERVER wrong n value") }
+			
+			message, n, err = Receive(trans)
+			if err != nil { log.Fatalln("SERVER receive:", err) }
+			log.Println("SERVER got message", message)
+			log.Println("SERVER got n",       n)
+			casted, ok = message.(MessagePing)
+			if !ok          { log.Fatalln("SERVER expected MessagePong") }
+			if casted != 78 { log.Fatalln("SERVER wrong message value") }
+			if n != 5       { log.Fatalln("SERVER wrong n value") }
+		}()
+
+		// client
+		go func() {
+			defer group.Done()
+
+			log.Println("CLIENT dialing")
+			conn, err := hopp.Dial(
+				context.Background(),
+				"tcp", "localhost:43957",
+				nil)
+			if err != nil { log.Fatalln("CLIENT dial:", err) }
+			defer conn.Close()
+			log.Println("CLIENT connected")
+
+			log.Println("CLIENT opening trans")
+			trans, err := conn.OpenTrans()
+			if err != nil { log.Fatalln("CLIENT open trans:", err) }
+			
+			message := MessagePing(77)
+			log.Println("CLIENT sending message")
+			n, err := Send(trans, &message)
+			if err != nil { log.Fatalln("CLIENT send:", err) }
+			log.Println("CLIENT sent n", n)
+			if n != 5 { log.Fatalln("CLIENT wrong n value") }
+			
+			message = MessagePing(78)
+			log.Println("CLIENT sending message")
+			n, err = Send(trans, &message)
+			if err != nil { log.Fatalln("CLIENT send:", err) }
+			log.Println("CLIENT sent n", n)
+			if n != 5 { log.Fatalln("CLIENT wrong n value") }
+		}()
+
+		group.Wait()
+	`)
+	
+}

generate/lex.go

@@ -10,22 +10,26 @@ const (
 	TokenMethod parse.TokenKind = iota
 	TokenKey
 	TokenIdent
+	TokenOption
 	TokenComma
 	TokenLBrace
 	TokenRBrace
 	TokenLBracket
 	TokenRBracket
+	TokenComment
 )
 
 var tokenNames = map[parse.TokenKind] string {
 	TokenMethod:   "Method",
 	TokenKey:      "Key",
 	TokenIdent:    "Ident",
+	TokenOption:   "Option",
 	TokenComma:    "Comma",
 	TokenLBrace:   "LBrace",
 	TokenRBrace:   "RBrace",
 	TokenLBracket: "LBracket",
 	TokenRBracket: "RBracket",
+	TokenComment:  "Comment",
 }
 
 func Lex(fileName string, reader io.Reader) (parse.Lexer, error) {
@@ -81,6 +85,18 @@ func (this *lexer) nextInternal() (token parse.Token, err error) {
 		}
 	}
 
+	unexpected := func() error {
+		if unicode.IsPrint(this.rune) {
+			return parse.Errorf (
+				this.pos(), "unexpected rune '%c'",
+				this.rune)
+		} else {
+			return parse.Errorf (
+				this.pos(), "unexpected rune %U",
+				this.rune)
+		}
+	}
+
 	defer func () {
 		newPos := this.pos()
 		newPos.End -- // TODO figure out why tf we have to do this
@@ -108,6 +124,11 @@ func (this *lexer) nextInternal() (token parse.Token, err error) {
 			if this.eof { err = nil; return }
 			if err != nil { return }
 		}
+	// Option
+	case this.rune == '?':
+		token.Kind = TokenOption
+		appendRune()
+		if this.eof { err = nil; return }
 	// Comma
 	case this.rune == ',':
 		token.Kind = TokenComma
@@ -133,14 +154,21 @@ func (this *lexer) nextInternal() (token parse.Token, err error) {
 		token.Kind = TokenRBracket
 		appendRune()
 		if this.eof { err = nil; return }
-	case unicode.IsPrint(this.rune):
-		err = parse.Errorf (
-			this.pos(), "unexpected rune '%c'",
-			this.rune)
+	// Comment
+	case this.rune == '/':
+		token.Kind = TokenComment
+		appendRune()
+		if this.eof { return }
+		if this.rune != '/' {
+			err = unexpected()
+			return
+		}
+		for this.rune != '\n' {
+			appendRune()
+			if this.eof { err = nil; return }
+		}
 	default:
-		err = parse.Errorf (
-			this.pos(), "unexpected rune %U",
-			this.rune)
+		err = unexpected()
 	}
 
 	return

generate/lex_test.go

@@ -6,14 +6,22 @@ import "git.tebibyte.media/sashakoshka/goparse"
 
 func TestLex(test *testing.T) {
 	lexer, err := Lex("test.pdl", strings.NewReader(`
+	// User holds profile information about a single user.
 	M0001 User {
 		0000 Name      String,
+		// dog water comment
+		
+		// Users is asdkjsagkj why
+		// 
+		// wow
 		0001 Users []User,
 		0002 Followers U32,
+		0003 Wings ?Int,
 	}`))
 	if err != nil { test.Fatal(parse.Format(err)) }
 
 	correctTokens := []parse.Token {
+		tok(TokenComment,  "// User holds profile information about a single user."),
 		tok(TokenMethod,   "0001"),
 		tok(TokenIdent,    "User"),
 		tok(TokenLBrace,   "{"),
@@ -21,6 +29,10 @@ func TestLex(test *testing.T) {
 		tok(TokenIdent,    "Name"),
 		tok(TokenIdent,    "String"),
 		tok(TokenComma,    ","),
+		tok(TokenComment,  "// dog water comment"),
+		tok(TokenComment,  "// Users is asdkjsagkj why"),
+		tok(TokenComment,  "// "),
+		tok(TokenComment,  "// wow"),
 		tok(TokenKey,      "0001"),
 		tok(TokenIdent,    "Users"),
 		tok(TokenLBracket, "["),
@@ -31,6 +43,11 @@ func TestLex(test *testing.T) {
 		tok(TokenIdent,    "Followers"),
 		tok(TokenIdent,    "U32"),
 		tok(TokenComma,    ","),
+		tok(TokenKey,      "0003"),
+		tok(TokenIdent,    "Wings"),
+		tok(TokenOption,   "?"),
+		tok(TokenIdent,    "Int"),
+		tok(TokenComma,    ","),
 		tok(TokenRBrace,   "}"),
 		tok(parse.EOF,     ""),
 	}

generate/misc_test.go

@@ -37,6 +37,7 @@ func testGenerateRun(test *testing.T, protocol *Protocol, title, imports, testCa
 		import "reflect"
 		import "git.tebibyte.media/sashakoshka/hopp/tape"
 		import tu "git.tebibyte.media/sashakoshka/hopp/internal/testutil"
+		import "git.tebibyte.media/sashakoshka/hopp/internal/testutil/snake"
 		` + imports
 	setup := `log.Println("*** BEGIN TEST CASE OUTPUT ***")`
 	teardown := `log.Println("--- END TEST CASE OUTPUT ---")`
@@ -61,8 +62,9 @@ func testGenerateRun(test *testing.T, protocol *Protocol, title, imports, testCa
 		func testDecode(correct Message, data any) {
 			var flat []byte
 			switch data := data.(type) {
-			case []byte:   flat = data
-			case tu.Snake: flat = data.Flatten()
+			case []byte:      flat = data
+			case tu.Snake:    flat = data.Flatten()
+			case snake.Snake: flat = data.Flatten()
 			}
 			message := reflect.New(reflect.ValueOf(correct).Elem().Type()).Interface().(Message)
 			log.Println("before: ", message)
@@ -79,9 +81,7 @@ func testGenerateRun(test *testing.T, protocol *Protocol, title, imports, testCa
 			}
 		}
 
-		// TODO: possibly combine the two above functions into this one,
-		// also take a data parameter here (snake)
-		func testEncodeDecode(message Message, data tu.Snake) {buffer := bytes.Buffer { }
+		func testEncodeDecode(message Message, data any) {buffer := bytes.Buffer { }
 			log.Println("encoding:")
 			encoder := tape.NewEncoder(&buffer)
 			n, err := message.Encode(encoder)
@@ -93,13 +93,30 @@ func testGenerateRun(test *testing.T, protocol *Protocol, title, imports, testCa
 			if n != len(got) {
 				log.Fatalf("n incorrect: %d != %d\n", n, len(got))
 			}
-			if ok, n := data.Check(got); !ok {
-				log.Fatalln("not equal at", n)
+			
+			var flat []byte
+			switch data := data.(type) {
+			case []byte:
+				flat = data
+				if ok, n := snake.Check(snake.L(data...), got); !ok {
+					log.Fatalln("not equal at", n)
+				}
+			case tu.Snake:
+				flat = data.Flatten()
+				if ok, n := data.Check(got); !ok {
+					log.Fatalln("not equal at", n)
+				}
+			case snake.Node:
+				flat = data.Flatten()
+				if ok, n := snake.Check(data, got); !ok {
+					log.Fatalln("not equal at", n)
+				}
+			default:
+				panic("AUSIAUGH AAAUUGUHGHGHH OUHGHGJDSGK")
 			}
 		
 			log.Println("decoding:")
 			destination := reflect.New(reflect.ValueOf(message).Elem().Type()).Interface().(Message)
-			flat := data.Flatten()
 			log.Println("before: ", tu.Describe(destination))
 			decoder := tape.NewDecoder(bytes.NewBuffer(flat))
 			n, err = destination.Decode(decoder)

generate/parse.go

@@ -1,6 +1,7 @@
 package generate
 
 import "io"
+import "strings"
 import "strconv"
 import "git.tebibyte.media/sashakoshka/goparse"
 
@@ -21,7 +22,7 @@ func Parse(lx parse.Lexer) (*Protocol, error) {
 func defaultProtocol() Protocol {
 	return Protocol {
 		Messages: make(map[uint16] Message),
-		Types: map[string] Type { },
+		Types: map[string] Typedef { },
 	}
 }
 
@@ -47,18 +48,28 @@ func (this *parser) parse() error {
 }
 
 func (this *parser) parseTopLevel() error {
-	err := this.ExpectDesc("message or typedef", TokenMethod, TokenIdent)
-	if err != nil { return err }
-	if this.EOF() { return nil }
+	doc := ""
+	for {
+		err := this.ExpectDesc("message or typedef", TokenMethod, TokenIdent, TokenComment)
+		if err != nil { return err }
+		if this.EOF() { return nil }
+		if this.Kind() == TokenComment {
+			if doc != "" { doc += "\n" }
+			doc += this.parseComment(this.Value())
+			this.Next()
+		} else {
+			break
+		}
+	}
 
 	switch this.Kind() {
-	case TokenMethod: return this.parseMessage()
-	case TokenIdent:  return this.parseTypedef()
+	case TokenMethod: return this.parseMessage(doc)
+	case TokenIdent:  return this.parseTypedef(doc)
 	}
 	panic("bug")
 }
 
-func (this *parser) parseMessage() error {
+func (this *parser) parseMessage(doc string) error {
 	err := this.Expect(TokenMethod)
 	if err != nil { return err }
 	method, err := this.parseHexNumber(this.Value(), 0xFFFF)
@@ -72,12 +83,13 @@ func (this *parser) parseMessage() error {
 	if err != nil { return err }
 	this.protocol.Messages[uint16(method)] = Message {
 		Name: name,
+		Doc:  doc,
 		Type: typ,
 	}
 	return nil
 }
 
-func (this *parser) parseTypedef() error {
+func (this *parser) parseTypedef(doc string) error {
 	err := this.Expect(TokenIdent)
 	if err != nil { return err }
 	name := this.Value()
@@ -85,7 +97,10 @@ func (this *parser) parseTypedef() error {
 	if err != nil { return err }
 	typ, err := this.parseType()
 	if err != nil { return err }
-	this.protocol.Types[name] = typ
+	this.protocol.Types[name] = Typedef {
+		Doc:  doc,
+		Type: typ,
+	}
 	return nil
 }
 
@@ -117,6 +132,7 @@ func (this *parser) parseType() (Type, error) {
 		case "Buffer": return TypeBuffer { }, this.Next()
 		case "Table":  return TypeTable { }, this.Next()
 		case "Any":    return TypeAny { }, this.Next()
+		case "Bool":   return TypeBool { }, this.Next()
 		}
 		return this.parseTypeNamed()
 	case TokenLBracket:
@@ -157,12 +173,22 @@ func (this *parser) parseTypeTable() (TypeTableDefined, error) {
 		Fields: make(map[uint16] Field),
 	}
 	for {
-		err := this.ExpectDesc("table field", TokenKey, TokenRBrace)
-		if err != nil { return TypeTableDefined { }, err }
+		doc := ""
+		for {
+			err := this.ExpectDesc("table field", TokenKey, TokenRBrace, TokenComment)
+			if err != nil { return TypeTableDefined { }, err }
+			if this.Kind() == TokenComment {
+				if doc != "" { doc += "\n" }
+				doc += this.parseComment(this.Value())
+				this.Next()
+			} else {
+				break
+			}
+		}
 		if this.Is(TokenRBrace) {
 			break
 		}
-		key, field, err := this.parseField()
+		key, field, err := this.parseField(doc)
 		if err != nil { return TypeTableDefined { }, err }
 		typ.Fields[key] = field
 		err = this.Expect(TokenComma, TokenRBrace)
@@ -178,7 +204,7 @@ func (this *parser) parseTypeTable() (TypeTableDefined, error) {
 	return typ, nil
 }
 
-func (this *parser) parseField() (uint16, Field, error) {
+func (this *parser) parseField(doc string) (uint16, Field, error) {
 	err := this.Expect(TokenKey)
 	if err != nil { return 0, Field { }, err }
 	key, err := this.parseHexNumber(this.Value(), 0xFFFF)
@@ -188,11 +214,19 @@ func (this *parser) parseField() (uint16, Field, error) {
 	name := this.Value()
 	err = this.Next()
 	if err != nil { return 0, Field { }, err }
+	option := false
+	if this.Kind() == TokenOption {
+		option = true
+		err = this.Next()
+		if err != nil { return 0, Field { }, err }
+	}
 	typ, err := this.parseType()
 	if err != nil { return 0, Field { }, err }
 	return uint16(key), Field {
-		Name: name,
-		Type: typ,
+		Name:   name,
+		Doc:    doc,
+		Type:   typ,
+		Option: option,
 	}, nil
 }
 
@@ -206,3 +240,7 @@ func (this *parser) parseHexNumber(input string, maxValue int64) (int64, error)
 	}
 	return number, nil
 }
+
+func (this *parser) parseComment(input string) string {
+	return strings.TrimPrefix(strings.TrimPrefix(input, "//"), " ")
+}

generate/parse_test.go

@@ -9,6 +9,7 @@ func TestParse(test *testing.T) {
 	correct := defaultProtocol()
 	correct.Messages[0x0000] = Message {
 		Name: "Connect",
+		Doc:  "Connect is sent from the client to the server as the first message of an\nauthenticated transaction.",
 		Type: TypeTableDefined {
 			Fields: map[uint16] Field {
 				0x0000: Field { Name: "Name",      Type: TypeString { } },
@@ -18,36 +19,52 @@ func TestParse(test *testing.T) {
 	}
 	correct.Messages[0x0001] = Message {
 		Name: "UserList",
+		Doc:  "UserList is sent from the server to the client in response to a Connect\nmessage.",
 		Type: TypeTableDefined {
 			Fields: map[uint16] Field {
 				0x0000: Field { Name: "Users",  Type: TypeArray { Element: TypeNamed { Name: "User" } } },
 			},
 		},
 	}
-	correct.Types["User"] = TypeTableDefined {
-		Fields: map[uint16] Field {
-			0x0000: Field { Name: "Name",      Type: TypeString { } },
-			0x0001: Field { Name: "Bio",       Type: TypeString { } },
-			0x0002: Field { Name: "Followers", Type: TypeInt { Bits: 32 } },
+	correct.Types["User"] = Typedef {
+		Doc:  "User holds profile information about a single user.",
+		Type: TypeTableDefined {
+			Fields: map[uint16] Field {
+				0x0000: Field { Name: "Name",      Type: TypeString { } },
+				0x0001: Field { Name: "Bio",       Type: TypeString { } },
+				0x0002: Field { Name: "Followers", Type: TypeInt { Bits: 32 } },
+				0x0003: Field { Name: "Bouncy",    Type: TypeBool { } },
+				0x0004: Field { Name: "Wings",     Type: TypeInt { Bits: 32 } },
+			},
 		},
 	}
-	correct.Types["Anything"] = TypeAny { }
+	correct.Types["Anything"] = Typedef {
+		Type: TypeAny { },
+	}
 	test.Log("CORRECT:", &correct)
 	
 	got, err := ParseReader("test.pdl", strings.NewReader(`
+	// Connect is sent from the client to the server as the first message of an
+	// authenticated transaction.
 	M0000 Connect {
 		0000 Name String,
+		// Password is where you put your secrets, your shameful secrets
 		0001 Password String,
 	}
 	
+	// UserList is sent from the server to the client in response to a Connect
+	// message.
 	M0001 UserList {
 		0000 Users []User,
 	}
 	
+	// User holds profile information about a single user.
 	User {
 		0000 Name      String,
 		0001 Bio       String,
 		0002 Followers U32,
+		0003 Bouncy    Bool,
+		0004 Wings     ?U32,
 	}
 
 	Anything Any

generate/protocol.go

@@ -7,11 +7,17 @@ import "crypto/md5"
 
 type Protocol struct {
 	Messages map[uint16] Message
-	Types    map[string] Type
+	Types    map[string] Typedef
 }
 
 type Message struct {
 	Name string
+	Doc  string
+	Type Type
+}
+
+type Typedef struct {
+	Doc  string
 	Type Type
 }
 
@@ -43,6 +49,12 @@ func (typ TypeFloat) String() string {
 	return fmt.Sprintf("F%d", typ.Bits)
 }
 
+type TypeBool struct { }
+
+func (TypeBool) String() string {
+	return "Bool"
+}
+
 type TypeString struct { }
 
 func (TypeString) String() string {
@@ -83,8 +95,10 @@ func (typ TypeTableDefined) String() string {
 }
 
 type Field struct {
-	Name string
-	Type Type
+	Name   string
+	Doc    string
+	Type   Type
+	Option bool
 }
 
 func (field Field) String() string {

go.mod

@@ -1,8 +1,9 @@
 module git.tebibyte.media/sashakoshka/hopp
 
-go 1.23.0
+go 1.24.0
 
 require (
-	git.tebibyte.media/sashakoshka/go-util v0.9.1
+	git.tebibyte.media/sashakoshka/go-cli v0.1.3
+	git.tebibyte.media/sashakoshka/go-util v0.11.0
 	git.tebibyte.media/sashakoshka/goparse v0.2.0
 )

go.sum

@@ -1,4 +1,6 @@
-git.tebibyte.media/sashakoshka/go-util v0.9.1 h1:eGAbLwYhOlh4aq/0w+YnJcxT83yPhXtxnYMzz6K7xGo=
-git.tebibyte.media/sashakoshka/go-util v0.9.1/go.mod h1:0Q1t+PePdx6tFYkRuJNcpM1Mru7wE6X+it1kwuOH+6Y=
+git.tebibyte.media/sashakoshka/go-cli v0.1.3 h1:tSkWjyx2JrGu6KotbXWSTKSYGGS1D4O3qwCrRoZuwbs=
+git.tebibyte.media/sashakoshka/go-cli v0.1.3/go.mod h1:JFA3wSdRkXxa4iQJWHfe3DokiG7Dh2XUJBzPmuVlbuY=
+git.tebibyte.media/sashakoshka/go-util v0.11.0 h1:ZxLJWHr0ecgVRV5O4MV7EGHK5xHJMppKd1P4x70AtYQ=
+git.tebibyte.media/sashakoshka/go-util v0.11.0/go.mod h1:0Q1t+PePdx6tFYkRuJNcpM1Mru7wE6X+it1kwuOH+6Y=
 git.tebibyte.media/sashakoshka/goparse v0.2.0 h1:uQmKvOCV2AOlCHEDjg9uclZCXQZzq2PxaXfZ1aIMiQI=
 git.tebibyte.media/sashakoshka/goparse v0.2.0/go.mod h1:tSQwfuD+EujRoKr6Y1oaRy74ZynatzkRLxjE3sbpCmk=

internal/connshark/connshark.go

@@ -0,0 +1,56 @@
+package connshark
+
+import "os"
+import "io"
+import "fmt"
+import "net"
+import "log"
+import "sync"
+import "math/rand"
+import tu "git.tebibyte.media/sashakoshka/hopp/internal/testutil"
+
+type insert struct {
+	net.Conn
+	output io.WriteCloser
+	lock sync.Mutex
+}
+
+func LogDebugFile(underlying net.Conn) net.Conn {
+	file, err := os.Create(fmt.Sprintf("connshark-%08X.log", rand.Uint32()))
+	if err != nil {
+		log.Println("XXX COULD NOT OPEN DEBUG FILE! reason: ", err)
+		return underlying
+	}
+	return Log(underlying, file)
+}
+
+func Log(underlying net.Conn, output io.WriteCloser) net.Conn {
+	return &insert {
+		Conn:   underlying,
+		output: output,
+	}
+}
+
+func (this *insert) Read(buffer []byte) (n int, err error) {
+	if n > 0 {
+		this.lock.Lock()
+		defer this.lock.Unlock()
+		fmt.Fprintf(this.output, "TX: %s\n", tu.HexBytes(buffer[:n]))
+	}
+	return n, err
+}
+
+func (this *insert) Write(buffer []byte) (n int, err error) {
+	n, err = this.Conn.Write(buffer)
+	if n > 0 {
+		this.lock.Lock()
+		defer this.lock.Unlock()
+		fmt.Fprintf(this.output, "RX: %s\n", tu.HexBytes(buffer[:n]))
+	}
+	return n, err
+}
+
+func (this *insert) Close() error {
+	this.output.Close()
+	return this.Conn.Close()
+}

internal/mock/connection.go

@@ -0,0 +1,64 @@
+package mock
+
+import "io"
+import "time"
+import "bytes"
+import "git.tebibyte.media/sashakoshka/hopp"
+
+var _ hopp.Trans = new(Trans)
+
+// Trans is a mock transaction implementation.
+type Trans struct {
+	// These arrays must be the same length. You can load this up
+	// with messages to read, or deposit messages and retrieve them
+	// here later.
+	Methods  []uint16
+	Messages [][]byte
+}
+
+func (this *Trans) Close() error { return nil }
+
+func (this *Trans) ID() int64 { return 56 }
+
+func (this *Trans) Send(method uint16, data []byte) error {
+	this.Methods  = append(this.Methods,  method)
+	this.Messages = append(this.Messages, data)
+	return nil
+}
+
+func (this *Trans) SendWriter(method uint16) (io.WriteCloser, error) {
+	return &transWriter {
+		Buffer: new(bytes.Buffer),
+		method: method,
+		parent: this,
+	}, nil
+}
+
+func (this *Trans) Receive() (method uint16, data []byte, err error) {
+	if len(this.Methods) == 0 {
+		return 0, nil, io.EOF
+	}
+	method = this.Methods[0]
+	data   = this.Messages[0]
+	this.Methods  = this.Methods[1:]
+	this.Messages = this.Messages[1:]
+	return method, data, nil
+}
+
+func (this *Trans) ReceiveReader() (method uint16, reader io.Reader, err error) {
+	method, data, err := this.Receive()
+	if err != nil { return 0, nil, err }
+	return method, bytes.NewBuffer(data), nil
+}
+
+func (this *Trans) SetDeadline(time.Time) error { return nil }
+
+type transWriter struct {
+	*bytes.Buffer
+	method uint16
+	parent *Trans
+}
+
+func (this *transWriter) Close() error {
+	return this.parent.Send(this.method, this.Bytes())
+}

internal/testutil/conn-recorder.go

@@ -0,0 +1,45 @@
+package testutil
+
+import "net"
+import "fmt"
+import "strings"
+
+var _ net.Conn = new(ConnRecorder)
+
+// ConnRecorder records write/flush actions performed on a net.Conn.
+type ConnRecorder struct {
+	net.Conn
+	// A []byte means data was written, and untyped nil
+	// means data was flushed.
+	Log []any
+}
+
+func RecordConn(underlying net.Conn) *ConnRecorder {
+	return &ConnRecorder {
+		Conn: underlying,
+	}
+}
+
+func (this *ConnRecorder) Write(data []byte) (n int, err error) {
+	this.Log = append(this.Log, data)
+	return len(data), nil
+}
+
+func (this *ConnRecorder) Flush() error {
+	this.Log = append(this.Log, nil)
+	return nil
+}
+
+func (this *ConnRecorder) Dump() string {
+	builder := strings.Builder { }
+	for index, item := range this.Log {
+		fmt.Fprintf(&builder, "%06d ", index)
+		switch item := item.(type) {
+		case nil:
+			fmt.Fprintln(&builder, "FLUSH")
+		case []byte:
+			fmt.Fprintln(&builder, HexBytes(item))
+		}
+	}
+	return builder.String()
+}

internal/testutil/conn-recorder_test.go

@@ -0,0 +1,44 @@
+package testutil
+
+import "net"
+import "testing"
+
+func TestConnRecorder(test *testing.T) {
+	// server
+	listener, err := net.Listen("tcp", "localhost:9999")
+	if err != nil { test.Fatal(err) }
+	defer listener.Close()
+	go func() {
+		conn, err := listener.Accept()
+		defer conn.Close()
+		if err != nil { test.Fatal(err) }
+		buf := [16]byte { }
+		for {
+			_, err := conn.Read(buf[:])
+			if err != nil { break }
+		}
+	}()
+
+	// client
+	conn, err := net.Dial("tcp", "localhost:9999")
+	if err != nil { test.Fatal(err) }
+	defer conn.Close()
+	recorder := RecordConn(conn)
+	
+	_, err = recorder.Write([]byte("hello"))
+	if err != nil { test.Fatal(err) }
+	_, err = recorder.Write([]byte("world!"))
+	if err != nil { test.Fatal(err) }
+	err = recorder.Flush()
+	if err != nil { test.Fatal(err) }
+
+	test.Log("GOT:\n" + recorder.Dump())
+
+	if len(recorder.Log) != 3 { test.Fatal("wrong length") }
+	if string(recorder.Log[0].([]byte)) != "hello" {
+		test.Fatal("not equal")
+	}
+	if string(recorder.Log[1].([]byte)) != "world!" {
+		test.Fatal("not equal")
+	}
+}

internal/testutil/snake/snake.go

@@ -0,0 +1,214 @@
+// Package snake lets you compare blocks of data where the ordering of certain
+// parts may be swapped every which way. It is designed for comparing the
+// encoding of maps where the ordering of individual elements is inconsistent.
+package snake
+
+import "fmt"
+import "strings"
+import tu "git.tebibyte.media/sashakoshka/hopp/internal/testutil"
+
+var _ Node = Order { }
+var _ Node = Snake { }
+var _ Node = Leaf  { }
+
+// Check checks the data against the specified node. If the data doesn't satisfy
+// the node, or the comparison succeded but didn't consume all the data, this
+// function returns false, and the index of the byte where the inequality is.
+func Check(node Node, data []byte) (ok bool, n int) {
+	ok, n = node.Check(data)
+	if !ok {
+		return false, n
+	}
+	if n != len(data) {
+		return false, n
+	}
+	return true, n
+}
+
+// O returns a new order given a vararg node slice.
+func O(nodes ...Node) Order {
+	return Order(nodes)
+}
+
+// S returns a new snake given a vararg node slice.
+func S(nodes ...Node) Snake {
+	return Snake(nodes)
+}
+
+// L returns a new leaf given a vararg byte slice.
+func L(data ...byte) Leaf {
+	return Leaf([]byte(data))
+}
+
+// Order is satisfied when the data satisfies each of its nodes in the order
+// that they are specified in the slice.
+type Order []Node
+
+// Check determines if the data satisfies the Order.
+func (this Order) Check(data []byte) (ok bool, n int) {
+	left := data
+	for _, node := range this {
+		ok, nn := node.Check(left)
+		n += nn; if !ok { return false, n }
+		left = left[nn:]
+	}
+	return true, n
+}
+
+// Flatten returns the Order flattened to a byte array. The result of this
+// function always satisfies the Order.
+func (this Order) Flatten() []byte {
+	flat := []byte { }
+	for _, node := range this {
+		flat = append(flat, node.Flatten()...)
+	}
+	return flat
+}
+
+func (this Order) String() string {
+	out := strings.Builder { }
+	for index, node := range this {
+		if index > 0 {
+			fmt.Fprint(&out, " :")
+		}
+		fmt.Fprintf(&out, " %v", node)
+	}
+	return out.String()
+}
+
+// Add returns a new order with the given nodes appended to it.
+func (this Order) Add(nodes ...Node) Order {
+	newOrder := make(Order, len(this) + len(nodes))
+	copy(newOrder, this)
+	copy(newOrder[len(this):], Order(nodes))
+	return newOrder
+}
+
+// AddO returns a new order with the given order appended to it.
+func (this Order) AddO(nodes ...Node) Order {
+	return this.Add(O(nodes...))
+}
+
+// AddS returns a new order with the given snake appended to it.
+func (this Order) AddS(nodes ...Node) Order {
+	return this.Add(S(nodes...))
+}
+
+// AddL returns a new order with the given leaf appended to it.
+func (this Order) AddL(data ...byte) Order {
+	return this.Add(L(data...))
+}
+
+// Snake is satisfied when the data satisfies each of its nodes in no particular
+// order.
+type Snake []Node
+
+// Check determines if the data satisfies the snake.
+func (this Snake) Check(data []byte) (ok bool, n int) {
+	fmt.Println("CHECKING SNAKE")
+	left := data
+	nodes := map[int] Node { }
+	for key, node := range this {
+		nodes[key] = node
+	}
+	for len(nodes) > 0 {
+		found := false
+		for key, node := range nodes {
+			fmt.Println(left, key, node)
+			ok, nn := node.Check(left)
+			fmt.Println(ok, nn)
+			if !ok { continue }
+			n += nn
+			left = data[n:]
+			delete(nodes, key)
+			found = true
+			break
+		}
+		if !found { return false, n }
+	}
+	return true, n
+}
+
+// Flatten returns the snake flattened to a byte array. The result of this
+// function always satisfies the snake.
+func (this Snake) Flatten() []byte {
+	flat := []byte { }
+	for _, node := range this {
+		flat = append(flat, node.Flatten()...)
+	}
+	return flat
+}
+
+func (this Snake) String() string {
+	out := strings.Builder { }
+	out.WriteString("[")
+	for index, node := range this {
+		if index > 0 {
+			fmt.Fprint(&out, " /")
+		}
+		fmt.Fprintf(&out, " %v", node)
+	}
+	out.WriteString(" ]")
+	return out.String()
+}
+
+// Add returns a new snake with the given nodes appended to it.
+func (this Snake) Add(nodes ...Node) Snake {
+	newSnake := make(Snake, len(this) + len(nodes))
+	copy(newSnake, this)
+	copy(newSnake[len(this):], Snake(nodes))
+	return newSnake
+}
+
+// AddO returns a new snake with the given order appended to it.
+func (this Snake) AddO(nodes ...Node) Snake {
+	return this.Add(O(nodes...))
+}
+
+// AddS returns a new snake with the given snake appended to it.
+func (this Snake) AddS(nodes ...Node) Snake {
+	return this.Add(S(nodes...))
+}
+
+// AddL returns a new snake with the given leaf appended to it.
+func (this Snake) AddL(data ... byte) Snake {
+	return this.Add(L(data...))
+}
+
+// Leaf is satisfied when the data matches it exactly.
+type Leaf []byte
+
+// Check determines if the data is equal to the leaf.
+func (this Leaf) Check(data []byte) (ok bool, n int) {
+	if len(data) < len(this) {
+		return false, len(data)
+	}
+	for index, byt := range this {
+		if byt != data[index] {
+			return false, index
+		}
+	}
+	return true, len(this)
+}
+
+// This one's easy.
+func (this Leaf) Flatten() []byte {
+	return []byte(this)
+}
+
+func (this Leaf) String() string {
+	return tu.HexBytes([]byte(this))
+}
+
+// Node represents a snake node.
+type Node interface {
+	// Check determines if the data satisfies the node. If satisfied, the function
+	// will return true, and the index at which it stopped. If not, the
+	// function will return false, and the index of the first byte that
+	// didn't match. As long as the start of the data satisfies the node,
+	// whatever comes after it doesn't matter.
+	Check(data []byte) (ok bool, n int)
+	// Flatten returns the node flattened to a byte array. The result of
+	// this function always satisfies the node.
+	Flatten() []byte
+}

internal/testutil/snake/snake_test.go

@@ -0,0 +1,89 @@
+package snake
+
+import "testing"
+
+func TestSnakeA(test *testing.T) {
+	snake := O().AddL(1, 6).AddS(
+		L(1),
+		L(2),
+		L(3),
+		L(4),
+		L(5),
+	).AddL(9)
+
+	test.Log(snake)
+
+	ok, n := Check(snake, []byte { 1, 6, 1, 2, 3, 4, 5, 9 })
+	if !ok { test.Fatal("false negative:", n) }
+	ok, n = Check(snake, []byte { 1, 6, 5, 4, 3, 2, 1, 9 })
+	if !ok { test.Fatal("false negative:", n) }
+	ok, n = Check(snake, []byte { 1, 6, 3, 1, 4, 2, 5, 9 })
+	if !ok { test.Fatal("false negative:", n) }
+	
+	ok, n = Check(snake, []byte { 1, 6, 9 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = Check(snake, []byte { 1, 6, 1, 2, 3, 4, 5, 6, 9 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = Check(snake, []byte { 1, 6, 0, 2, 3, 4, 5, 6, 9 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = Check(snake, []byte { 1, 6, 7, 1, 4, 2, 5, 9 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = Check(snake, []byte { 1, 6, 7, 3, 1, 4, 2, 5, 9 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = Check(snake, []byte { 1, 6, 7, 3, 1, 4, 2, 5, 9 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = Check(snake, []byte { 1, 6, 1, 2, 3, 4, 5, 9, 10})
+	if ok { test.Fatal("false positive:", n) }
+}
+
+func TestSnakeB(test *testing.T) {
+	snake := O().AddO(L(1), L(6)).AddS(
+		L(1),
+		L(2),
+	).AddL(9).AddS(
+		L(3, 2),
+		L(0),
+		L(1, 1, 2, 3),
+	)
+
+	test.Log(snake)
+
+	ok, n := Check(snake, []byte { 1, 6, 1, 2, 9, 3, 2, 0, 1, 1, 2, 3})
+	if !ok { test.Fatal("false negative:", n) }
+	ok, n = Check(snake, []byte { 1, 6, 2, 1, 9, 0, 1, 1, 2, 3, 3, 2})
+	if !ok { test.Fatal("false negative:", n) }
+	
+	ok, n = Check(snake, []byte { 1, 6, 9 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = Check(snake, []byte { 1, 6, 1, 2, 9 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = Check(snake, []byte { 1, 6, 9, 3, 2, 0, 1, 1, 2, 3})
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = Check(snake, []byte { 1, 6, 2, 9, 0, 1, 1, 2, 3, 3, 2})
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = Check(snake, []byte { 1, 6, 1, 2, 9, 3, 2, 1, 1, 2, 3})
+	if ok { test.Fatal("false positive:", n) }
+}
+
+func TestSnakeC(test *testing.T) {
+	snake := S(
+		L(1, 2, 3),
+		S(L(6), L(7), L(8)),
+	)
+
+	test.Log(snake)
+
+	ok, n := Check(snake, []byte { 1, 2, 3, 6, 7, 8 })
+	if !ok { test.Fatal("false negative:", n) }
+	ok, n = Check(snake, []byte { 6, 7, 8, 1, 2, 3 })
+	if !ok { test.Fatal("false negative:", n) }
+	ok, n = Check(snake, []byte { 7, 8, 6, 1, 2, 3 })
+	if !ok { test.Fatal("false negative:", n) }
+	ok, n = Check(snake, []byte { 1, 2, 3, 8, 6, 7 })
+	if !ok { test.Fatal("false negative:", n) }
+
+	ok, n = Check(snake, []byte { 2, 1, 3, 6, 7, 8 })
+	if ok { test.Fatal("false positive:", n) }
+	ok, n = Check(snake, []byte { 6, 1, 2, 3, 7, 8 })
+	if ok { test.Fatal("false positive:", n) }
+}

internal/testutil/testutil.go

@@ -97,6 +97,32 @@ func (sn Snake) String() string {
 	return out.String()
 }
 
+func (sn Snake) CharsString() string {
+	if len(sn) == 0 || len(sn[0]) == 0 || len(sn[0][0]) == 0 {
+		return "EMPTY"
+	}
+
+	out := strings.Builder { }
+	for index, sector := range sn {
+		if index > 0 { out.WriteString(" : ") }
+		out.WriteRune('[')
+		for index, variation := range sector {
+			if index > 0 { out.WriteString(" / ") }
+			for _, byt := range variation {
+				run := rune(byt)
+				if unicode.IsPrint(run) && run < 0x7F {
+					out.WriteRune(run)
+				} else {
+					out.WriteRune('.')
+				}
+				out.WriteRune(' ')
+			}
+		}
+		out.WriteRune(']')
+	}
+	return out.String()
+}
+
 // HexBytes formats bytes into a hexadecimal string.
 func HexBytes(data []byte) string {
 	if len(data) == 0 { return "EMPTY" }
@@ -107,6 +133,24 @@ func HexBytes(data []byte) string {
 	return out.String()
 }
 
+// HexChars returns all printable bytes in the string, with non-printable ones
+// replaced with a dot. Each character has an extra space after it for placing
+// underneath the result of HexBytes.
+func HexChars(data []byte) string {
+	if len(data) == 0 { return "EMPTY" }
+	out := strings.Builder { }
+	for _, byt := range data {
+		run := rune(byt)
+		if unicode.IsPrint(run) && run < 0x7F {
+			out.WriteRune(run)
+		} else {
+			out.WriteRune('.')
+		}
+		out.WriteRune(' ')
+	}
+	return out.String()
+}
+
 // Describe returns a string representing the type and data of the given value.
 func Describe(value any) string {
 	desc := describer { }

listen.go

@@ -15,14 +15,34 @@ type Listener interface {
 	Addr() net.Addr
 }
 
-// Listen listens for incoming HOPP connections. The network must be one of
-// "quic", "quic4", (IPv4-only) "quic6" (IPv6-only), or "unix". For now, quic is
-// not supported.
-func Listen(network, address string) (Listener, error) {
+// Listen listens for incoming HOPP connections. The network must be one of:
+// 
+// - "quic"
+// - "quic4" (IPv4-only)
+// - "quic6" (IPv6-only)
+// - "tls"
+// - "tls4" (IPv4-only)
+// - "tls6" (IPv6-only)
+// - "tcp"
+// - "tcp4" (IPv4-only)
+// - "tcp6" (IPv6-only)
+// - "unix"
+//
+// For now, QUIC is unsupported.
+func Listen(network, address string, tlsConf *tls.Config) (Listener, error) {
 	switch network {
-	case "quic", "quic4", "quic6": return ListenQUIC(network, address, nil)
-	case "unix":                   return ListenUnix(network, address)
-	default:                       return nil, ErrUnknownNetwork
+	case "quic", "quic4", "quic6": return ListenQUIC(network, address, tlsConf)
+	case "tls", "tls4", "tls6":    return ListenTLS(network, address, tlsConf)
+	case "tcp", "tcp4", "tcp6":
+		addr, err := net.ResolveTCPAddr(network, address)
+		if err != nil { return nil, err }
+		return ListenTCP(network, addr)
+	case "unix":
+		addr, err := net.ResolveUnixAddr(network, address)
+		if err != nil { return nil, err }
+		return ListenUnix(network, addr)
+	default:
+		return nil, ErrUnknownNetwork
 	}
 }
 
@@ -34,33 +54,52 @@ func ListenQUIC(network, address string, tlsConf *tls.Config) (Listener, error)
 	return nil, errors.New("quic is not yet implemented")
 }
 
-// ListenUnix listens for incoming HOPP connections using a Unix domain socket
-// as a transport. The network must be "unix".
-func ListenUnix(network, address string) (Listener, error) {
-	if network != "unix" { return nil, ErrUnknownNetwork }
-	addr, err := net.ResolveUnixAddr(network, address)
+// ListenTLS listens for incoming HOPP connections using a TLS socket as a
+// transport. The network must be "tcp".
+func ListenTLS(network, address string, tlsConf *tls.Config) (Listener, error) {
+	network, err := tlsNetworkToTCPNetwork(network)
 	if err != nil { return nil, err }
-	unixListener, err := net.ListenUnix(network, addr)
+	listener, err := tls.Listen(network, address, tlsConf)
 	if err != nil { return nil, err }
-	return &listenerUnix {
-		underlying: unixListener,
+	return &netListenerWrapper {
+		underlying: listener,
 	}, nil
 }
 
-type listenerUnix struct {
-	underlying *net.UnixListener
+// ListenTCP listens for incoming HOPP connections using a TCP socket as a
+// transport. The network must be "tcp".
+func ListenTCP(network string, laddr *net.TCPAddr) (Listener, error) {
+	listener, err := net.ListenTCP(network, laddr)
+	if err != nil { return nil, err }
+	return &netListenerWrapper {
+		underlying: listener,
+	}, nil
 }
 
-func (this *listenerUnix) Accept() (Conn, error) {
+// ListenUnix listens for incoming HOPP connections using a Unix domain socket
+// as a transport. The network must be "unix".
+func ListenUnix(network string, addr *net.UnixAddr) (Listener, error) {
+	listener, err := net.ListenUnix(network, addr)
+	if err != nil { return nil, err }
+	return &netListenerWrapper {
+		underlying: listener,
+	}, nil
+}
+
+type netListenerWrapper struct {
+	underlying net.Listener
+}
+
+func (this *netListenerWrapper) Accept() (Conn, error) {
 	conn, err := this.underlying.Accept()
 	if err != nil { return nil, err }
 	return AdaptA(conn, ServerSide), nil
 }
 
-func (this *listenerUnix) Close() error {
+func (this *netListenerWrapper) Close() error {
 	return this.underlying.Close()
 }
 
-func (this *listenerUnix) Addr() net.Addr {
+func (this *netListenerWrapper) Addr() net.Addr {
 	return this.underlying.Addr()
 }

metadapta.go

@@ -6,6 +6,8 @@ import "fmt"
 import "net"
 import "sync"
 import "time"
+import "bytes"
+import "context"
 import "sync/atomic"
 import "git.tebibyte.media/sashakoshka/go-util/sync"
 
@@ -16,6 +18,12 @@ const closeMethod = 0xFFFF
 const int64Max = int64((^uint64(0)) >> 1)
 const defaultChunkSize = 0x1000
 
+var bufferPool = sync.Pool {
+	New: func() any {
+		return &bytes.Buffer { }
+	},
+}
+
 // Party represents a side of a connection.
 type Party bool; const (
 	ServerSide Party = false
@@ -39,20 +47,23 @@ type a struct {
 	sendLock     sync.Mutex
 	transMap     map[int64] *transA
 	transChan    chan *transA
-	done         chan struct { }
+	ctx          context.Context
+	done         func()
 	err          error
 }
 
 // AdaptA returns a connection implementing METADAPT-A over a singular stream-
 // oriented transport such as TCP or UNIX domain stream sockets.
 func AdaptA(underlying net.Conn, party Party) Conn {
+	ctx, done := context.WithCancel(context.Background())
 	conn := &a {
 		sizeLimit:  defaultSizeLimit,
 		underlying: underlying,
 		party:      party,
 		transMap:   make(map[int64] *transA),
 		transChan:  make(chan *transA),
-		done:       make(chan struct { }),
+		ctx:        ctx,
+		done:       done,
 	}
 	if party == ClientSide {
 		conn.transID =  1
@@ -60,11 +71,15 @@ func AdaptA(underlying net.Conn, party Party) Conn {
 		conn.transID = -1
 	}
 	go conn.receive()
+	go func() {
+		<- ctx.Done()
+		underlying.Close()
+	}()
 	return conn
 }
 
 func (this *a) Close() error {
-	close(this.done)
+	this.done()
 	return nil
 }
 
@@ -105,7 +120,7 @@ func (this *a) AcceptTrans() (Trans, error) {
 			return nil, eof
 		}
 		return trans, nil
-	case <- this.done:
+	case <- this.ctx.Done():
 		return nil, eof
 	}
 }
@@ -124,10 +139,10 @@ func (this *a) unlistTransactionSafe(id int64) {
 	delete(this.transMap, id)
 }
 
-func (this *a) sendMessageSafe(trans int64, method uint16, data []byte) error {
+func (this *a) sendMessageSafe(trans int64, method uint16, ccb uint64, data []byte) error {
 	this.sendLock.Lock()
 	defer this.sendLock.Unlock()
-	return encodeMessageA(this.underlying, this.sizeLimit, trans, method, data)
+	return encodeMessageA(this.underlying, this.sizeLimit, trans, method, 0, data)
 }
 
 func (this *a) receive() {
@@ -214,12 +229,12 @@ type transA struct {
 	parent        *a
 	id            int64
 	incoming      usync.Gate[incomingMessage]
-	currentReader io.Reader
-	currentWriter io.Closer
-	writeBuffer   []byte
 	closed        atomic.Bool
 	closeErr      error
 	
+	currentReader  io.Reader
+	currentWriter  usync.Monitor[io.Closer]
+	
 	deadline      *time.Timer
 	deadlineLock  sync.Mutex
 }
@@ -251,27 +266,28 @@ func (this *transA) ID() int64 {
 }
 
 func (this *transA) Send(method uint16, data []byte) error {
-	return this.parent.sendMessageSafe(this.id, method, data)
+	return this.parent.sendMessageSafe(this.id, method, 0, data)
 }
 
 func (this *transA) SendWriter(method uint16) (io.WriteCloser, error) {
+	currentWriter, done := this.currentWriter.BorrowReturn()
+	defer done(&currentWriter)
+
 	// close previous writer if necessary
-	if this.currentWriter != nil {
-		this.currentWriter.Close()
-		this.currentWriter = nil
+	if currentWriter != nil {
+		currentWriter.Close()
+		currentWriter = nil
 	}
 
 	// create new writer
 	writer := &writerA {
 		parent: this,
-		// there is only ever one writer at a time, so they can all
-		// share a buffer
-		buffer: this.writeBuffer[:0],
+		buffer: bufferPool.Get().(*bytes.Buffer),
 		method: method,
 		chunkSize: defaultChunkSize,
 		open: true,
 	}
-	this.currentWriter = writer
+	currentWriter = writer
 	return writer, nil
 }
 
@@ -382,7 +398,7 @@ func (this *readerA) pull() (uint16, error) {
 	// close and return error on failure
 	this.eof = true
 	this.parent.Close()
-	return 0, fmt.Errorf("could not receive message: %w", this.parent.bestErr())
+	return 0, this.parent.bestErr()
 }
 
 func (this *readerA) Read(buffer []byte) (int, error) {
@@ -398,14 +414,14 @@ func (this *readerA) Read(buffer []byte) (int, error) {
 
 type writerA struct {
 	parent    *transA
-	buffer    []byte
+	buffer    *bytes.Buffer
 	method    uint16
 	chunkSize int64
 	open      bool
 }
 
 func (this *writerA) Write(data []byte) (n int, err error) {
-	if !this.open { return 0, io.EOF }
+	if !this.open || this.parent.closed.Load() { return 0, io.EOF }
 	toSend := data
 	for len(toSend) > 0 {
 		nn, err := this.writeOne(toSend)
@@ -417,7 +433,18 @@ func (this *writerA) Write(data []byte) (n int, err error) {
 }
 
 func (this *writerA) Close() error {
-	this.open = false
+	if this.buffer != nil {
+		// flush if needed
+		if this.buffer.Len() > 0 {
+			this.flush(0)
+		}
+		this.open = false
+
+		// reset the buffer and put it back in the pool
+		this.buffer.Reset()
+		bufferPool.Put(this.buffer)
+		this.buffer = nil
+	}
 	return nil
 }
 
@@ -425,26 +452,31 @@ func (this *writerA) writeOne(data []byte) (n int, err error) {
 	data = data[:min(len(data), int(this.chunkSize))]
 	
 	// if there is more room, append to the buffer and exit
-	if int64(len(this.buffer) + len(data)) <= this.chunkSize {
-		this.buffer = append(this.buffer, data...)
+	if int64(this.buffer.Len() + len(data)) <= this.chunkSize {
+		this.buffer.Write(data)
 		n = len(data)
 		// if have a full chunk, flush
-		if int64(len(this.buffer)) == this.chunkSize {
-			err = this.flush()
+		if int64(this.buffer.Len()) == this.chunkSize {
+			err = this.flush(1)
 			if err != nil { return n, err }
 		}
 		return n, nil
 	}
 
 	// if not, flush and store as much as we can in the buffer
-	err = this.flush()
+	err = this.flush(1)
 	if err != nil { return n, err }
-	this.buffer = append(this.buffer, data...)
+	n = int(min(int64(len(data)), this.chunkSize))
+	this.buffer.Write(data[:n])
 	return n, nil
 }
 
-func (this *writerA) flush() error {
-	return this.parent.parent.sendMessageSafe(this.parent.id, this.method, this.buffer)
+func (this *writerA) flush(ccb uint64) error {
+	err := this.parent.parent.sendMessageSafe(
+		this.parent.id, this.method, ccb,
+		this.buffer.Bytes())
+	this.buffer.Reset()
+	return err
 }
 
 type incomingMessage struct {
@@ -458,15 +490,19 @@ func encodeMessageA(
 	sizeLimit int64,
 	trans     int64,
 	method    uint16,
+	ccb       uint64,
 	data      []byte,
 ) error {
 	if int64(len(data)) > sizeLimit {
 		return ErrPayloadTooLarge
 	}
 	buffer := make([]byte, 18 + len(data))
+	// transaction ID field
 	encodeI64(buffer[:8], trans)
+	// method field
 	encodeI16(buffer[8:10], method)
-	encodeI64(buffer[10:18], uint64(len(data)))
+	// payload size field
+	encodeI64(buffer[10:18], uint64(len(data)) & 0x7FFFFFFFFFFFFFFF | ccb << 63)
 	copy(buffer[18:], data)
 	_, err := writer.Write(buffer)
 	return err
@@ -485,6 +521,7 @@ func decodeMessageA(
 	headerBuffer := [18]byte { }
 	_, err = io.ReadFull(reader, headerBuffer[:])
 	if err != nil { return 0, 0, false, nil, err }
+	
 	transID, err = decodeI64[int64](headerBuffer[:8])
 	if err != nil { return 0, 0, false, nil, err }
 	method, err = decodeI16[uint16](headerBuffer[8:10])

metadapta_test.go

@@ -2,10 +2,13 @@ package hopp
 
 import "io"
 import "net"
+import "sync"
 import "bytes"
 import "errors"
 import "slices"
 import "testing"
+import "context"
+import tu "git.tebibyte.media/sashakoshka/hopp/internal/testutil"
 
 // some of these tests spawn goroutines that can signal a failure.
 // abide by the documentation for testing.T (https://pkg.go.dev/testing#T):
@@ -52,6 +55,7 @@ func TestConnA(test *testing.T) {
 			test.Error("CLIENT payload:", gotPayload)
 			test.Fatal("CLIENT ok byeeeeeeeeeeeee")
 		}
+		test.Log("CLIENT transaction has closed")
 	}
 	
 	serverFunc := func(a Conn) {
@@ -70,20 +74,6 @@ func TestConnA(test *testing.T) {
 }
 
 func TestTransOpenCloseA(test *testing.T) {
-	// currently:
-	//
-	//    | data sent | data recvd | close sent | close recvd
-	// 10 |     X     |     X      |      X     | server hangs
-	// 20 |     X     |     X      |      X     | client hangs
-	// 30 |     X     |            |      X     |
-	//
-	// when a close message is recvd, it tries to push to the trans and
-	// hangs on trans.incoming.Send, which hangs on sending the value to the
-	// underlying channel. why is this?
-	//
-	// check if we are really getting values from the channel when pulling
-	// from the trans channel when we are expecting a close.
-	
 	clientFunc := func(conn Conn) {
 		// 10
 		trans, err := conn.OpenTrans()
@@ -142,10 +132,71 @@ func TestTransOpenCloseA(test *testing.T) {
 	clientServerEnvironment(test, clientFunc, serverFunc)
 }
 
+func TestReadWriteA(test *testing.T) {
+	payloads := []string {
+		"hello",
+		"world",
+		"When the impostor is sus!",
+	}
+
+	clientFunc := func(a Conn) {
+		test.Log("CLIENT accepting transaction")
+		trans, err := a.AcceptTrans()
+		if err != nil { test.Fatal("CLIENT", err) }
+		test.Log("CLIENT accepted transaction")
+		test.Cleanup(func() { trans.Close() })
+		for method, payload := range payloads {
+			test.Log("CLIENT waiting...")
+			gotMethod, gotReader, err := trans.ReceiveReader()
+			if err != nil { test.Fatal("CLIENT", err) }
+			gotPayloadBytes, err := io.ReadAll(gotReader)
+			if err != nil { test.Fatal("CLIENT", err) }
+			gotPayload := string(gotPayloadBytes)
+			test.Log("CLIENT m:", gotMethod, "p:", tu.HexBytes(gotPayloadBytes))
+			if int(gotMethod) != method {
+				test.Error("CLIENT method not equal, expected", method)
+			}
+			if gotPayload != payload {
+				test.Error(
+					"CLIENT payload not equal, expected",
+					tu.HexBytes([]byte(payload)))
+			}
+		}
+		test.Log("CLIENT waiting for transaction close...")
+		gotMethod, gotPayload, err := trans.Receive()
+		if !errors.Is(err, io.EOF) {
+			test.Error("CLIENT wrong error:", err)
+			test.Error("CLIENT    method:", gotMethod)
+			test.Error("CLIENT    payload:", tu.HexBytes(gotPayload))
+			test.Fatal("CLIENT    (expected io.EOF and no message)")
+		}
+		test.Log("CLIENT transaction has closed")
+	}
+	
+	serverFunc := func(a Conn) {
+		defer test.Log("SERVER closing connection")
+		trans, err := a.OpenTrans()
+		if err != nil { test.Error("SERVER", err); return }
+		test.Cleanup(func() { trans.Close() })
+		for method, payload := range payloads {
+			test.Log("SERVER m:", method, "p:", tu.HexBytes([]byte(payload)))
+			func() {
+				writer, err := trans.SendWriter(uint16(method))
+				if err != nil { test.Error("SERVER", err); return }
+				defer writer.Close()
+				_, err = writer.Write([]byte(payload))
+				if err != nil { test.Error("SERVER", err); return }
+			}()
+		}
+	}
+
+	clientServerEnvironment(test, clientFunc, serverFunc)
+}
+
 func TestEncodeMessageA(test *testing.T) {
 	buffer := new(bytes.Buffer)
 	payload := []byte { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05 }
-	err := encodeMessageA(buffer, defaultSizeLimit, 0x5800FEABC3104F04, 0x6B12, payload)
+	err := encodeMessageA(buffer, defaultSizeLimit, 0x5800FEABC3104F04, 0x6B12, 0, payload)
 	correct := []byte {
 		0x58, 0x00, 0xFE, 0xAB, 0xC3, 0x10, 0x4F, 0x04,
 		0x6B, 0x12,
@@ -163,7 +214,7 @@ func TestEncodeMessageA(test *testing.T) {
 func TestEncodeMessageAErr(test *testing.T) {
 	buffer := new(bytes.Buffer)
 	payload := make([]byte, 0x10000)
-	err := encodeMessageA(buffer, 0x20, 0x5800FEABC3104F04, 0x6B12, payload)
+	err := encodeMessageA(buffer, 0x20, 0x5800FEABC3104F04, 0x6B12, 0, payload)
 	if !errors.Is(err, ErrPayloadTooLarge) {
 		test.Fatalf("wrong error: %v", err)
 	}
@@ -208,7 +259,7 @@ func TestEncodeDecodeMessageA(test *testing.T) {
 	correctMethod  := uint16(30)
 	correctPayload := []byte("good")
 	buffer := bytes.Buffer { }
-	err := encodeMessageA(&buffer, defaultSizeLimit, correctTransID, correctMethod, correctPayload)
+	err := encodeMessageA(&buffer, defaultSizeLimit, correctTransID, correctMethod, 0, correctPayload)
 	if err != nil { test.Fatal(err) }
 	transID, method, chunked, payload, err := decodeMessageA(&buffer, defaultSizeLimit)
 	if got, correct := transID, int64(2); got != correct {
@@ -225,39 +276,255 @@ func TestEncodeDecodeMessageA(test *testing.T) {
 	}
 }
 
+func TestConsecutiveSend(test *testing.T) {
+	packets := [][]byte {
+		[]byte {
+			0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+			0x00, 0x00,
+			0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x05,
+			0x43, 0x00, 0x00, 0x00, 0x07 },
+		
+		[]byte {
+			0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+			0x00, 0x00,
+			0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x05,
+			0x43, 0x00, 0x00, 0x00, 0x08 },
+	}
+	payloads := [][]byte {
+		[]byte { 0x43, 0x00, 0x00, 0x00, 0x07 },
+		[]byte { 0x43, 0x00, 0x00, 0x00, 0x08 },
+	}
+
+	var group sync.WaitGroup
+	group.Add(2)
+
+	// server
+	listener, err := net.Listen("tcp", "localhost:9999")
+	if err != nil { test.Fatal("SERVER", err) }
+	go func() {
+		defer group.Done()
+		defer listener.Close()
+		conn, err := listener.Accept()
+		if err != nil { test.Fatal("SERVER", err) }
+		defer conn.Close()
+		
+		buf := [16]byte { }
+		for {
+			_, err := conn.Read(buf[:])
+			if err != nil { break }
+		}
+	}()
+
+	// client
+	go func() {
+		defer group.Done()
+		conn, err := net.Dial("tcp", "localhost:9999")
+		if err != nil { test.Fatal("CLIENT", err) }
+		defer conn.Close()
+		recorder := tu.RecordConn(conn)
+
+		a := AdaptA(recorder, ClientSide)
+		trans, err := a.OpenTrans()
+		if err != nil { test.Fatal("CLIENT", err) }
+
+		for _, payload := range payloads {
+			err := trans.Send(0x0000, payload)
+			if err != nil { test.Fatal("CLIENT", err) }
+		}
+
+		test.Log("CLIENT recorded output:\n" + recorder.Dump())
+		if len(recorder.Log) != 2 { test.Fatal("wrong length") }
+		if !slices.Equal(recorder.Log[0].([]byte), packets[0]) {
+			test.Fatal("not equal")
+		}
+		if !slices.Equal(recorder.Log[1].([]byte), packets[1]) {
+			test.Fatal("not equal")
+		}
+	}()
+
+	group.Wait()
+}
+
+func TestConsecutiveWrite(test *testing.T) {
+	packets := [][]byte {
+		[]byte {
+			0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+			0x00, 0x00,
+			0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x05,
+			0x43, 0x00, 0x00, 0x00, 0x07 },
+		
+		[]byte {
+			0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+			0x00, 0x00,
+			0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x05,
+			0x43, 0x00, 0x00, 0x00, 0x08 },
+	}
+	payloads := [][]byte {
+		[]byte { 0x43, 0x00, 0x00, 0x00, 0x07 },
+		[]byte { 0x43, 0x00, 0x00, 0x00, 0x08 },
+	}
+
+	var group sync.WaitGroup
+	group.Add(2)
+
+	// server
+	listener, err := net.Listen("tcp", "localhost:9999")
+	if err != nil { test.Fatal("SERVER", err) }
+	go func() {
+		defer group.Done()
+		defer listener.Close()
+		conn, err := listener.Accept()
+		if err != nil { test.Fatal("SERVER", err) }
+		defer conn.Close()
+		
+		buf := [16]byte { }
+		for {
+			_, err := conn.Read(buf[:])
+			if err != nil { break }
+		}
+	}()
+
+	// client
+	go func() {
+		defer group.Done()
+		conn, err := net.Dial("tcp", "localhost:9999")
+		if err != nil { test.Fatal("CLIENT", err) }
+		defer conn.Close()
+		recorder := tu.RecordConn(conn)
+
+		a := AdaptA(recorder, ClientSide)
+		trans, err := a.OpenTrans()
+		if err != nil { test.Fatal("CLIENT", err) }
+
+		for _, payload := range payloads {
+			func() {
+				writer, err := trans.SendWriter(0x0000)
+				if err != nil { test.Fatal("CLIENT", err) }
+				_, err = writer.Write(payload)
+				if err != nil { test.Fatal("CLIENT", err) }
+				writer.Close()	
+			}()
+		}
+
+		test.Log("CLIENT recorded output:\n" + recorder.Dump())
+		if len(recorder.Log) != 2 { test.Fatal("wrong length") }
+		if !slices.Equal(recorder.Log[0].([]byte), packets[0]) {
+			test.Fatal("not equal")
+		}
+		if !slices.Equal(recorder.Log[1].([]byte), packets[1]) {
+			test.Fatal("not equal")
+		}
+	}()
+
+	group.Wait()
+}
+
+func TestConsecutiveReceive(test *testing.T) {
+	stream := []byte {
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+		0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x05,
+		0x43, 0x00, 0x00, 0x00, 0x07,
+
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+		0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x05,
+		0x43, 0x00, 0x00, 0x00, 0x08,
+	}
+	payloads := [][]byte {
+		[]byte { 0x43, 0x00, 0x00, 0x00, 0x07 },
+		[]byte { 0x43, 0x00, 0x00, 0x00, 0x08 },
+	}
+
+	var group sync.WaitGroup
+	group.Add(2)
+
+	// server
+	listener, err := net.Listen("tcp", "localhost:9999")
+	if err != nil { test.Fatal("SERVER", err) }
+	go func() {
+		defer group.Done()
+		defer listener.Close()
+		conn, err := listener.Accept()
+		if err != nil { test.Fatal("SERVER", err) }
+		defer conn.Close()
+		
+		a := AdaptA(conn, ServerSide)
+		trans, err := a.AcceptTrans()
+		if err != nil { test.Fatal("SERVER", err) }
+		index := 0
+		for {
+			method, data, err := trans.Receive()
+			if err != nil {
+				if !errors.Is(err, io.EOF) {
+					test.Fatal("SERVER", err)
+				}
+				break
+			}
+			test.Logf("SERVER GOT: M%04X %s", method, tu.HexBytes(data))
+			if index >= len(payloads) {
+				test.Fatalf(
+					"SERVER we weren't supposed to receive %d messages",
+					index + 1)
+			}
+			if method != 0 {
+				test.Fatal("SERVER", "method not equal")
+			}
+			if !slices.Equal(data, payloads[index]) {
+				test.Fatal("SERVER", "data not equal")
+			}
+			index ++
+		}
+		if index != len(payloads) {
+			test.Fatalf(
+				"SERVER we weren't supposed to receive %d messages",
+				index + 1)
+		}
+	}()
+
+	// client
+	go func() {
+		defer group.Done()
+		conn, err := net.Dial("tcp", "localhost:9999")
+		if err != nil { test.Fatal("CLIENT", err) }
+		defer conn.Close()
+		_, err = conn.Write(stream)
+		if err != nil { test.Fatal("CLIENT", err) }
+	}()
+
+	group.Wait()
+}
+
 func clientServerEnvironment(test *testing.T, clientFunc func(conn Conn), serverFunc func(conn Conn)) {
 	network := "tcp"
 	addr := "localhost:7959"
 
 	// server
-	listener, err := net.Listen(network, addr)
-	if err != nil { test.Fatal(err) }
+	listener, err := Listen(network, addr, nil)
 	test.Cleanup(func() { listener.Close() })
 	go func() {
 		test.Log("SERVER listening")
 		conn, err := listener.Accept()
 		if err != nil { test.Error("SERVER", err); return }
+
 		defer conn.Close()
 		test.Cleanup(func() { conn.Close() })
-		a := AdaptA(conn, ServerSide)
-		test.Cleanup(func() { a.Close() })
-
-		serverFunc(a)
+		
+		serverFunc(conn)
 		test.Log("SERVER closing")
 	}()
 
 	// client
 	test.Log("CLIENT dialing")
-	conn, err := net.Dial(network, addr)
+	conn, err := Dial(context.Background(), network, addr, nil)
 	if err != nil { test.Fatal("CLIENT", err) }
+	test.Cleanup(func() { conn.Close() })
 	test.Log("CLIENT dialed")
-	a := AdaptA(conn, ClientSide)
-	test.Cleanup(func() { a.Close() })
 
-	clientFunc(a)
+	clientFunc(conn)
 	
 	test.Log("CLIENT waiting for connection close...")
-	trans, err := a.AcceptTrans()
+	trans, err := conn.AcceptTrans()
 	if !errors.Is(err, io.EOF) {
 		test.Error("CLIENT wrong error:", err)
 		test.Fatal("CLIENT trans:", trans)

option.go

@@ -2,29 +2,10 @@ package hopp
 
 import "git.tebibyte.media/sashakoshka/go-util/container"
 
-// Option allows an optional value to be defined without using a pointer.
-// TODO make generic alias once go 1.24 releases
-type Option[T any] ucontainer.Optional[T]
+// Option is an alias for ucontainer.Option, defined here for convenience
+type Option[T any] = ucontainer.Option[T]
 
+// O is an alias for ucontainer.O, defined here for convenience
 func O[T any](value T) Option[T] {
-	return Option[T](ucontainer.O(value))
-}
-
-func Void[T any]() Option[T] {
-	return Option[T](ucontainer.Void[T]())
-}
-
-func (option Option[T]) Ok() bool {
-	return (ucontainer.Optional[T])(option).Exists()
-}
-
-func (option Option[T]) Get() (T, bool) {
-	return (ucontainer.Optional[T])(option).Value()
-}
-
-func (option Option[T]) Default(defaul T) T {
-	if value, ok := option.Get(); ok {
-		return value
-	}
-	return defaul
+	return ucontainer.O(value)
 }

pdl.yaml

@@ -0,0 +1,20 @@
+filetype: pdl
+
+detect:
+        filename: "\\.pdl$"
+
+rules:
+        - preproc: "\\bM[0-9a-fA-F]{4}\\b"
+
+        - type: "\\b((U|I)(5|8|16|32|64|128|256)|F(16|32|64|128|256)|Bool|String|Buffer|Table|Any)\\b"
+
+        - symbol.brackets: "(\\{|\\}|\\[\\])"
+        - symbol.operator: "\\?"
+
+        - constant.number: "\\b[0-9a-fA-F]{4}\\b"
+
+        - comment:
+                start: "//"
+                end: "$"
+                rules:
+                        - todo: "(TODO|XXX|FIXME|BUG):?"

tape/dynamic.go

@@ -6,6 +6,10 @@ package tape
 // TODO: add support for struct tags: `tape:"0000"`, tape:"0001"` so they can get
 // transformed into tables with a defined schema
 
+// TODO: support special behavior for options in structs: don't just write a
+// zero value if the option is void, write no field at all. also consider doing
+// this for maps, and maybe slices.
+
 // TODO: test all of these smaller functions individually
 
 // For an explanation as to why this package always treats LBA/SBA as strings,
@@ -59,6 +63,7 @@ func EncodeAny(encoder *Encoder, value any, tag Tag) (n int, err error) {
 	case reflect.Uint64:  return encoder.WriteUint64(uint64(reflectValue.Uint()))
 	case reflect.Float32: return encoder.WriteFloat32(float32(reflectValue.Float()))
 	case reflect.Float64: return encoder.WriteFloat64(float64(reflectValue.Float()))
+	case reflect.Bool:    return // SI has no payload
 	case reflect.String:
 		if reflectValue.Len() > MaxStructureLength {
 			return 0, ErrTooLong
@@ -78,6 +83,12 @@ func EncodeAny(encoder *Encoder, value any, tag Tag) (n int, err error) {
 		return n, nil
 	}
 
+	// option
+	if isTypeOption(reflectValue.Type()) {
+		elemValue, _ := optionValue(reflectValue) // zero value for free
+		return EncodeAny(encoder, elemValue, tag)
+	}
+	
 	// aggregates
 	reflectType := reflect.TypeOf(value)
 	switch reflectType.Kind() {
@@ -252,8 +263,8 @@ func decodeAnyOrError(decoder *Decoder, destination reflect.Value, tag Tag) (n i
 		// not we receive an empty any value) actually makes it fucking
 		// work. go figure().
 		//
-		// (the map allocation functionality in skeletonPointer has been
-		// removed)
+		// (the map allocation functionality in skeletonPointer was
+		// removed after this comment was written)
 		value := reflect.MakeMapWithSize(reflect.TypeOf(dummyMap), lengthCast)
 		destination.Set(value)
 		destination = value
@@ -298,11 +309,23 @@ func tagAny(reflectValue reflect.Value) (Tag, error) {
 	case reflect.Uint64:  return LI.WithCN(7), nil
 	case reflect.Float32: return FP.WithCN(3), nil
 	case reflect.Float64: return FP.WithCN(7), nil
+	case reflect.Bool:
+		if reflectValue.Bool() {
+			return SI.WithCN(1), nil
+		} else {
+			return SI.WithCN(0), nil
+		}
 	case reflect.String:  return bufferLenTag(reflectValue.Len()), nil
 	}
 	if reflectValue.CanConvert(reflect.TypeOf(dummyBuffer)) {
 		return bufferLenTag(reflectValue.Len()), nil
 	}
+
+	// option
+	if isTypeOption(reflectValue.Type()) {
+		elem, _ := optionValue(reflectValue) // zero value for free
+		return tagAny(elem)
+	}
 	
 	// aggregates
 	reflectType := reflectValue.Type()
@@ -329,9 +352,14 @@ func encodeAnySlice(encoder *Encoder, value any, tag Tag) (n int, err error) {
 	for index := 0; index < reflectValue.Len(); index += 1 {
 		itemTag, err := tagAny(reflectValue.Index(index))
 		if err != nil { return n, err }
+		if itemTag.Is(SBA) {
+			// SBA data in an LBA will always have the tag LBA:0,
+			// because 32 <= 256
+			continue
+		}
 		if itemTag.CN() > oneTag.CN() { oneTag = itemTag }
 	}
-	if oneTag.Is(SBA) { oneTag += 1 << 5 }
+	if oneTag.Is(SBA) { oneTag = LBA.WithCN(oneTag.CN()) }
 	nn, err = encoder.WriteUint8(uint8(oneTag))
 	n += nn; if err != nil { return n, err }
 	for index := 0; index < reflectValue.Len(); index += 1 {
@@ -374,7 +402,8 @@ func canSet(destination reflect.Type, tag Tag) error {
 		switch destination.Kind() {
 		case
 			reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
-			reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+			reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
+			reflect.Bool:
 		default:
 			return errCantAssignf("cannot assign integer to %v", destination)
 		}
@@ -432,6 +461,8 @@ func setInt(destination reflect.Value, value int64, bytes int) {
 // setUint expects a settable destination.
 func setUint(destination reflect.Value, value uint64, bytes int) {
 	switch {
+	case destination.Kind() == reflect.Bool:
+		destination.Set(reflect.ValueOf(value > 0))
 	case destination.CanInt():
 		destination.Set(reflect.ValueOf(int64(value)).Convert(destination.Type()))
 	case destination.CanUint():
@@ -566,6 +597,21 @@ func isTypeAny(typ reflect.Type) bool {
 	return typ.Kind() == reflect.Interface && typ.NumMethod() == 0
 }
 
+// isTypeOption returns whether the given reflect.Type is a ucontainer.Option,
+// and returns the element type if true.
+func isTypeOption(typ reflect.Type) bool {
+	// TODO: change when needed
+	goutilPath := "git.tebibyte.media/sashakoshka/go-util"
+	return typ.Name() == "Option" && typ.PkgPath() == goutilPath + "/container"
+}
+
+// optionValue returns the value of an option. The value MUST be an option, or
+// this function will panic.
+func optionValue(value reflect.Value) (elem reflect.Value, ok bool) {
+	result := value.MethodByName("Value").Call([]reflect.Value { })
+	return result[0], result[1].Bool()
+}
+
 // peekSlice returns the element tag and dimension count of the OTA currently
 // being decoded. It does not use up the decoder, it only peeks.
 func peekSlice(decoder *Decoder, tag Tag) (Tag, int, error) {

tape/dynamic_test.go

@@ -3,37 +3,10 @@ package tape
 import "bytes"
 import "testing"
 import "reflect"
+import "git.tebibyte.media/sashakoshka/go-util/container"
 import tu "git.tebibyte.media/sashakoshka/hopp/internal/testutil"
 
-var samplePayloads = [][]byte {
-	/* int8     */ []byte { byte(LSI.WithCN(0)), 0x45 },
-	/* int16    */ []byte { byte(LSI.WithCN(1)), 0x45, 0x67 },
-	/* int32    */ []byte { byte(LSI.WithCN(3)), 0x45, 0x67, 0x89, 0xAB },
-	/* int64    */ []byte { byte(LSI.WithCN(7)), 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23 },
-	/* uint5    */ []byte { byte(SI.WithCN(12)) },
-	/* uint8    */ []byte { byte(LI.WithCN(0)), 0x45 },
-	/* uint16   */ []byte { byte(LI.WithCN(1)), 0x45, 0x67 },
-	/* uint32   */ []byte { byte(LI.WithCN(3)), 0x45, 0x67, 0x89, 0xAB },
-	/* uint64   */ []byte { byte(LI.WithCN(7)), 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23 },
-	/* string   */ []byte { byte(SBA.WithCN(7)), 'p', 'u', 'p', 'e', 'v', 'e', 'r' },
-	/* []byte   */ []byte { byte(SBA.WithCN(5)), 'b', 'l', 'a', 'r', 'g' },
-	/* []string */ []byte {
-		byte(OTA.WithCN(0)), 2, byte(LBA.WithCN(0)),
-		0x08, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23,
-		0x05, 0x11, 0x11, 0x11, 0x11, 0x11,
-	},
-	/* map[uint16] any */ []byte {
-		byte(KTV.WithCN(0)), 2,
-		0x02, 0x23, byte(LSI.WithCN(1)), 0x45, 0x67,
-		0x02, 0x24, byte(LI.WithCN(3)),  0x45, 0x67, 0x89, 0xAB,
-	},
-	/* map[uint16] any */ []byte {
-		byte(KTV.WithCN(0)), 3,
-		0x00, 0x01, 0x63, 0x43, 0xF4, 0xC0, 0x00,
-		0x00, 0x02, 0x82, 'h', 'i',
-		0x00, 0x03, 0x21, 0x39, 0x92,
-	},
-}
+var samplePayloads [][]byte
 
 var sampleValues = []any {
 	/* int8     */ int8(0x45),
@@ -45,6 +18,8 @@ var sampleValues = []any {
 	/* uint16   */ uint16(0x4567),
 	/* uint32   */ uint32(0x456789AB),
 	/* uint64   */ uint64(0x456789ABCDEF0123),
+	/* bool     */ false,
+	/* bool     */ true,
 	/* string   */ "pupever",
 	/* []byte   */ "blarg",
 	/* []string */ []string {
@@ -60,6 +35,64 @@ var sampleValues = []any {
 		0x0002: "hi",
 		0x0003: uint16(0x3992),
 	},
+	// IMPORTANT: ONLY ADD AT THE END!!!! DO NOT MOVE WHAT IS ALREADY HERE!
+	// IMPORTANT: ONLY ADD AT THE END!!!! DO NOT MOVE WHAT IS ALREADY HERE!
+}
+
+type sample struct {
+	t Tag
+	v any
+	s tu.Snake
+}
+
+var samples = []sample {
+	/* int8     */ sample { t: LSI.WithCN(0), s: tu.S(0x45) },
+	/* int16    */ sample { t: LSI.WithCN(1), s: tu.S(0x45, 0x67) },
+	/* int32    */ sample { t: LSI.WithCN(3), s: tu.S(0x45, 0x67, 0x89, 0xAB) },
+	/* int64    */ sample { t: LSI.WithCN(7), s: tu.S(0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23) },
+	/* uint5    */ sample { t: SI.WithCN(12), s: tu.S() },
+	/* uint8    */ sample { t: LI.WithCN(0),  s: tu.S(0x45) },
+	/* uint16   */ sample { t: LI.WithCN(1),  s: tu.S(0x45, 0x67) },
+	/* uint32   */ sample { t: LI.WithCN(3),  s: tu.S(0x45, 0x67, 0x89, 0xAB) },
+	/* uint64   */ sample { t: LI.WithCN(7),  s: tu.S(0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23) },
+	/* bool     */ sample { t: SI.WithCN(0),  s: tu.S() },
+	/* bool     */ sample { t: SI.WithCN(1),  s: tu.S() },
+	/* string   */ sample { t: SBA.WithCN(7), s: tu.S('p', 'u', 'p', 'e', 'v', 'e', 'r') },
+	/* []byte   */ sample { t: SBA.WithCN(5), s: tu.S('b', 'l', 'a', 'r', 'g') },
+	/* []string */ sample {
+		t: OTA.WithCN(0),
+		s: tu.S(2, byte(LBA.WithCN(0)),
+			0x08, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23,
+			0x05, 0x11, 0x11, 0x11, 0x11, 0x11),
+	},
+	/* map[uint16] any */ sample {
+		t: KTV.WithCN(0),
+		s: tu.S(2).AddVar(
+			[]byte { 0x02, 0x23, byte(LSI.WithCN(1)), 0x45, 0x67 },
+			[]byte { 0x02, 0x24, byte(LI.WithCN(3)),  0x45, 0x67, 0x89, 0xAB }),
+	},
+	/* map[uint16] any */ sample {
+		t: KTV.WithCN(0),
+		s: tu.S(3).AddVar(
+			[]byte { 0x00, 0x01, 0x63, 0x43, 0xF4, 0xC0, 0x00 },
+			[]byte { 0x00, 0x02, 0x82, 'h', 'i' },
+			[]byte { 0x00, 0x03, 0x21, 0x39, 0x92 }),
+	},
+}
+
+var sampleOptionValues []any
+
+func init() {
+	sampleOptionValues = make([]any, len(sampleValues))
+	for index, value := range sampleValues {
+		sampleOptionValues[index] = ucontainer.O(value)
+		samples[index].v = value
+	}
+	samplePayloads = make([][]byte, len(samples))
+	for index, sample := range samples {
+		item := append([]byte { byte(sample.t) }, sample.s.Flatten()...)
+		samplePayloads[index] = item
+	}
 }
 
 type userDefinedInteger int16
@@ -84,7 +117,9 @@ func TestEncodeAnyTable(test *testing.T) {
 		0x3456: userDefinedInteger(0x3921),
 		0x1F1F: float32(67.26),
 		0x0F0F: float64(5.3),
-	}, KTV.WithCN(0), tu.S(9).AddVar(
+		0xAAAA: false,
+		0xBBBB: true,
+	}, KTV.WithCN(0), tu.S(11).AddVar(
 		[]byte {
 			0xF3, 0xB9,
 			byte(LSI.WithCN(3)),
@@ -138,6 +173,14 @@ func TestEncodeAnyTable(test *testing.T) {
 			byte(FP.WithCN(7)),
 			0x40, 0x15, 0x33, 0x33, 0x33, 0x33, 0x33, 0x33,
 		},
+		[]byte {
+			0xAA, 0xAA,
+			byte(SI.WithCN(0)),
+		},
+		[]byte {
+			0xBB, 0xBB,
+			byte(SI.WithCN(1)),
+		},
 	))
 	if err != nil { test.Fatal(err) }
 }
@@ -146,7 +189,7 @@ func TestDecodeWrongType(test *testing.T) {
 	for index, data := range samplePayloads {
 		test.Logf("data %2d %v [%s]", index, Tag(data[0]), tu.HexBytes(data[1:]))
 		// integers should only assign to other integers
-		if index > 8 {
+		if index > 10 {
 			cas := func(destination any) {
 				n, err := DecodeAnyInto(NewDecoder(bytes.NewBuffer(data[1:])), destination, Tag(data[0]))
 				if err != nil { test.Fatalf("error: %v | n: %d", err, n) }
@@ -155,7 +198,7 @@ func TestDecodeWrongType(test *testing.T) {
 					if reflectValue.Int() != 0 {
 						test.Fatalf("destination not zero: %v", reflectValue.Elem().Interface())
 					}
-				} else {
+				} else if reflectValue.Kind() != reflect.Bool {
 					if reflectValue.Uint() != 0 {
 						test.Fatalf("destination not zero: %v", reflectValue.Elem().Interface())
 					}
@@ -180,6 +223,8 @@ func TestDecodeWrongType(test *testing.T) {
 			{ var dest uint32; cas(&dest) }
 			test.Log("- uint64")
 			{ var dest uint64; cas(&dest) }
+			test.Log("- bool")
+			{ var dest bool; cas(&dest) }
 		}
 		arrayCase := func(destination any) {
 			n, err := DecodeAnyInto(NewDecoder(bytes.NewBuffer(data[1:])), destination, Tag(data[0]))
@@ -194,19 +239,19 @@ func TestDecodeWrongType(test *testing.T) {
 			}
 		}
 		// SBA/LBA types should only assign to other SBA/LBA types
-		if index != 9 && index != 10 {
+		if index != 11 && index != 12 {
 			test.Log("- string")
 			{ var dest string; arrayCase(&dest) }
 			test.Log("- []byte")
 			{ var dest []byte; arrayCase(&dest) }
 		}
 		// arrays should only assign to other arrays
-		if index != 11 {
+		if index != 13 {
 			test.Log("- []string")
 			{ var dest []string; arrayCase(&dest) }
 		}
 		// tables should only assign to other tables
-		if index != 12 && index != 13 {
+		if index != 14 && index != 15 {
 			test.Log("- map[uint16] any")
 			{ var dest = map[uint16] any { }; arrayCase(&dest) }
 		}
@@ -231,6 +276,12 @@ func TestEncodeDecodeAnyTable(test *testing.T) {
 func TestEncodeDecodeAnyDestination(test *testing.T) {
 	var destination any
 	for index, data := range samplePayloads {
+		if _, isBool := sampleValues[index].(bool); isBool {
+			// test is invalid for bools because they are never
+			// created as a skeleton value
+			continue
+		}
+	
 		tag     := Tag(data[0])
 		payload := data[1:]
 		test.Logf("data %2d %v [%s]", index, tag, tu.HexBytes(payload))
@@ -249,6 +300,20 @@ func TestEncodeDecodeAnyDestination(test *testing.T) {
 	}
 }
 
+func TestEncodeOption(test *testing.T) {
+	for _, sample := range samples {
+		snake   := sample.s
+		tag     := sample.t
+		value   := sample.v
+		if _, ok := value.(bool); tag.Is(SI) && !ok {
+			// we will never encode an SI unless its a bool
+			continue
+		}
+		err := testEncodeAny(test, value, tag, snake)
+		if err != nil { test.Fatal(err) }
+	}
+}
+
 func TestPeekSlice(test *testing.T) {
 	buffer := bytes.NewBuffer([]byte {
 		2, byte(OTA.WithCN(3)),
@@ -349,6 +414,12 @@ func TestTagAny(test *testing.T) {
 
 func TestDecodeAny(test *testing.T) {
 	for index, payload := range samplePayloads {
+		if _, isBool := sampleValues[index].(bool); isBool {
+			// test is invalid for bools because they are never
+			// created as a skeleton value
+			continue
+		}
+		
 		correctValue := sampleValues[index]
 		data := payload[1:]
 		decoder := NewDecoder(bytes.NewBuffer(data))

tape/misc_test.go

@@ -32,7 +32,9 @@ func testEncodeAny(test *testing.T, value any, correctTag Tag, correctBytes tu.S
 	test.Log("n:      ", n)
 	test.Log("tag:    ", tag)
 	test.Log("got:    ", tu.HexBytes(bytes))
+	test.Log("   :    ", tu.HexChars(bytes))
 	test.Log("correct:", correctBytes)
+	test.Log("       :", correctBytes.CharsString())
 	if tag != correctTag {
 		return fmt.Errorf("tag not equal: %v != %v", tag, correctTag)
 	}
@@ -56,6 +58,7 @@ func testEncodeDecodeAny(test *testing.T, value, correctValue any) error {
 	test.Log("n:  ", n)
 	test.Log("tag:", tag)
 	test.Log("got:", tu.HexBytes(bytes))
+	test.Log("   :", tu.HexChars(bytes))
 	test.Log("decoding...", tag)
 	if n != len(bytes) {
 		return fmt.Errorf("n not equal: %d != %d", n, len(bytes))