Improve doc comments for ApplicationSystem*Dirs

contents

README.md

@@ -2,12 +2,79 @@
 
 [![Go Reference](https://pkg.go.dev/badge/git.tebibyte.media/tomo/nasin.svg)](https://pkg.go.dev/git.tebibyte.media/tomo/nasin)
 
-Nasin provides an easy way to write applications with Tomo. To get started, take
+Nasin builds an application framework on top of Tomo to ease and encourage the
-a look at the [examples](examples) directory and the
+development of consistent and stable application software. It has these
+wonderful features, and more:
+
+- Use the Application interface to create applications with relatively low
+  boilerplate
+- CLI argument parsing and URI opening
+- Automatic setup/teardown of the backend
+- Advanced configuration system that can watch config files for changes
+- Default style and icon set, as well as a fully featured stylesheet language
+  for creating custom styles, and support for XDG icon themes
+
+## Getting Started
+Here is a basic "hello world" application, with explanations as comments:
+```go
+package main
+
+import "image"
+import "git.tebibyte.media/tomo/nasin"
+import "git.tebibyte.media/tomo/objects"
+import "git.tebibyte.media/tomo/objects/layouts"
+
+func main () {
+	nasin.RunApplication(new(Application))
+}
+
+type Application struct { }
+
+// Describe returns the application's name and ID, and optionally what type of
+// application it is.
+func (this *Application) Describe () nasin.ApplicationDescription {
+	return nasin.ApplicationDescription {
+		// This is the name of the application. New application windows
+		// will have this as their title by default.
+		Name: "Example",
+		// This is a "well-known" name, which typically is a domain name
+		// owned by the application author.
+		ID: "com.example.Example",
+	}
+}
+
+// Init performs initial setup of the application. Since this is a single-window
+// application that doesn't open any files, we create the window here.
+func (this *Application) Init () error {
+	// Passing an empty rectangle when creating a new window will cause it
+	// to auto-expand to fit the minimum size of its contents.
+	window, err := nasin.NewApplicationWindow(this, image.Rectangle { })
+	if err != nil { return err }
+	// Here we create a new container with a basic vertical layout, place a
+	// text label that says "Hello world!" in it, and set it as the root
+	// object of the window.
+	window.SetRoot(objects.NewOuterContainer (
+		layouts.ContractVertical,
+		objects.NewLabel("Hello world!")))
+	window.SetVisible(true)
+	// Nasin will not exit until all windows it is "waiting for" have
+	// been closed.
+	nasin.WaitFor(window)
+	return nil
+}
+
+// Stop cleanly closes things like system resources or background tasks. We do
+// not have any here, so nothing is done.
+func (this *Application) Stop () { }
+```
+
+To learn more, take a look at the [examples](examples) directory and the
 [online documentation](https://pkg.go.dev/git.tebibyte.media/tomo/nasin).
 
-Related repositories:
+## Related Repositories
 - [Tomo API](https://git.tebibyte.media/tomo/tomo): The API that all other parts
   of the toolkit agree on
 - [Objects](https://git.tebibyte.media/tomo/objects): A standard collection of
   re-usable objects and other GUI components
+- [Backend](https://git.tebibyte.media/tomo/backend): The software responsible
+  for managing and rendering things behind the scenes

application.go

@@ -6,9 +6,10 @@ import "flag"
 import "image"
 import "strings"
 import "net/url"
+import "path/filepath"
 import "git.tebibyte.media/tomo/tomo"
 import "git.tebibyte.media/tomo/objects"
-import "git.tebibyte.media/tomo/tomo/canvas"
+import "git.tebibyte.media/tomo/nasin/config"
 import "git.tebibyte.media/tomo/nasin/internal/registrar"
 
 // Application represents an application object.
@@ -17,7 +18,11 @@ type Application interface {
 	Describe () ApplicationDescription
 
 	// Init performs the initial setup of the application.
-	Init () error
+	Init () (error)
+
+	// Stop stops the application and does not return until all ongoing
+	// operations have been completely shut down.
+	Stop ()
 }
 
 // ApplicationURLOpener is an application that can open a URL.
@@ -33,9 +38,8 @@ type ApplicationURLOpener interface {
 	OpenURL (*url.URL) error
 
 	// OpenNone is called when the application is launched without any URLs
-	// to open. The application may create some sort of default starting
+	// to open.
-	// window, or call tomo.Stop().
+	OpenNone () error
-	OpenNone ()
 }
 
 // ApplicationFlagAdder is an application that supports reading command line
@@ -66,6 +70,15 @@ type ApplicationDescription struct {
 	Role ApplicationRole
 }
 
+// GlobalApplicationDescription returns the global application description which
+// points to cache, data, config, etc. used by Nasin itself.
+func GlobalApplicationDescription () ApplicationDescription {
+	return ApplicationDescription {
+		Name: "Nasin",
+		ID:   "xyz.holanet.Nasin",
+	}
+}
+
 // String satisfies the fmt.Stringer interface.
 func (application ApplicationDescription) String () string {
 	if application.Name == "" {
@@ -120,8 +133,9 @@ func (role ApplicationRole) Icon () tomo.Icon {
 	}
 }
 
-// RunApplication is like tomo.Run, but runs an application. If something fails
+// RunApplication is like tomo.Run, but runs an application. It automatically
-// to initialize, an error is written to the standard logger.
+// sets up a backend. If something fails to initialize, an error is written to
+// the standard logger.
 func RunApplication (application Application) {
 	// TODO: see #4
 
@@ -130,19 +144,59 @@ func RunApplication (application Application) {
 	}
 	flag.Parse()
 
-	err := registrar.RegisterBackend()
+	// open config
-	if err != nil { log.Fatalln("nasin: could not register backend:", err) }
+	globalConfig, err := ApplicationConfig(GlobalApplicationDescription())
-	err = tomo.Run(func () {
+	if err != nil { log.Fatalln("nasin: could not open config:", err) }
-		err := registrar.SetTheme()
+	currentGlobalConfig = globalConfig
-		if err != nil { log.Fatalln("nasin: could not set theme:", err) }
+	defer func () {
-		err = application.Init()
+		globalConfig.Close()
-		if err != nil { log.Fatalln("nasin: could not run application:", err) }
+		currentGlobalConfig = nil
+	} ()
+	styleConfigKey   := "Style"
+	iconSetConfigKey := "IconSet"
 
-		// open URLs
+	// registry
-		args := flag.Args()
+	// TODO: rebuild registry around the config
-		applicationOpenUrls(application, args...)
+	reg := new(registrar.Registrar)
+	backend, err := reg.SetBackend()
+	if err != nil { log.Fatalln("nasin: could not register backend:", err) }
+	err = reg.SetFaceSet()
+	if err != nil { log.Fatalln("nasin: could not set face set:", err) }
+	updateStyle := func () {
+		value, err := globalConfig.GetString(styleConfigKey, "")
+		if err != nil { log.Fatalln("nasin: could not set theme:", err) }
+		err = reg.SetStyle(value)
+		if err != nil { log.Fatalln("nasin: could not set theme:", err) }
+	}
+	updateIconSet := func () {
+		value, err := globalConfig.GetString(iconSetConfigKey, "")
+		if err != nil { log.Fatalln("nasin: could not set icon set:", err) }
+		err = reg.SetIconSet(value)
+		if err != nil { log.Fatalln("nasin: could not set icon set:", err) }
+	}
+	updateStyle()
+	updateIconSet()
+
+	globalConfig.OnChange(func (key string) {
+		switch key {
+		case styleConfigKey:   updateStyle()
+		case iconSetConfigKey: updateIconSet()
+		}
 	})
+
+	// init application
+	err = application.Init()
 	if err != nil { log.Fatalln("nasin: could not run application:", err) }
+
+	// open URLs
+	args := flag.Args()
+	applicationOpenUrls(application, args...)
+
+	if manager.count > 0 {
+		err = backend.Run()
+		if err != nil { log.Fatalln("nasin: could not run application:", err) }
+	}
+	application.Stop()
 }
 
 // NewApplicationWindow creates a window for an application. It will
@@ -160,64 +214,101 @@ func NewApplicationWindow (application Application, bounds image.Rectangle) (tom
 	return window, nil
 }
 
-func applicationOpenUrls (application Application, args ...string) {
+// ApplicationConfig opens a new config for the specified application. It must
-	if application, ok := application.(ApplicationURLOpener); ok {
+// be closed when it is no longer needed.
-		if len(args) <= 0 {
+func ApplicationConfig (app ApplicationDescription) (config.ConfigCloser, error) {
-			application.OpenNone()
+	user, err := ApplicationUserConfigDir(app)
-		}
+	if err != nil { return nil, err }
+	user = filepath.Join(user, "config.conf")
+	system, err := ApplicationSystemConfigDirs(app)
+	if err != nil { return nil, err }
+	for index, path := range system {
+		system[index] = filepath.Join(path, "config.conf")
+	}
+	return config.NewConfig(user, system...)
+}
 
-		openedAny := false
+var currentGlobalConfig config.Config
-		for _, arg := range flag.Args() {
+// GlobalConfig returns the global config. It contains options that apply to
-			ur, err := url.Parse(arg)
+// Tomo/Nasin itself, such as the style sheet and the icon set. This is managed
-			if err != nil {
+// by Nasin and must not be closed by the application.
-				log.Fatalf (
+func GlobalConfig () config.Config {
-					"nasin: invalid URL %v: %v",
+	return currentGlobalConfig
-					arg, err)
+}
-			}
+
-			if ur.Scheme == "" {
+func errorPopupf (title, format string, v ...any) func (func ()) {
-				ur.Scheme = "file"
+	return func (callback func ()) {
-			}
+		dialog, err := objects.NewDialogOk (
-			err = application.OpenURL(ur)
+			objects.DialogError, nil,
-			if err != nil {
+			title,
-				dialog, err := objects.NewDialogOk (
+			fmt.Sprintf(format, v...),
-					objects.DialogError, nil,
+			callback)
-					"Could Not Open URL",
+		if err != nil { log.Fatal(err) }
-					fmt.Sprintf (
+		dialog.SetVisible(true)
-						"Could not open %v: %v",
+		WaitFor(dialog)
-						arg, err),
+	}
-					func () {
+}
-						if !openedAny {
+
-							application.OpenNone()
+func applicationOpenUrls (app Application, args ...string) {
-						}
+	application, ok := app.(ApplicationURLOpener)
-					})
+	if !ok {
-				if err != nil { log.Fatal(err) }
-				dialog.SetVisible(true)
-			}
-		}
-	} else {
 		if len(args) > 0 {
 			log.Fatal("nasin: this application cannot open URLs")
 		}
+		return
+	}
+	
+	openNone := func () bool {
+		err := application.OpenNone()
+		if err != nil {
+			log.Fatalf("nasin: could not open main window: %v", err)
+			return false
+		}
+		return true
+	}
+	
+	if len(args) <= 0 {
+		openNone()
+		return
+	}
+
+	openedAny := false
+	for _, arg := range flag.Args() {
+		ur, err := url.Parse(arg)
+		if err != nil {
+			log.Fatalf (
+				"nasin: invalid URL %v: %v",
+				arg, err)
+		}
+		if ur.Scheme == "" {
+			ur.Scheme = "file"
+		}
+		err = application.OpenURL(ur)
+		if err != nil {
+			errorPopupf(
+				"Could Not Open URL",
+				"Could not open %v: %v",
+				arg, err,
+			)(func () {
+				if !openedAny {
+					openNone()
+				}
+			})
+		}
 	}
 }
 
 func setApplicationWindowIcon (window tomo.Window, description ApplicationDescription) {
-	allSizes := func (icon tomo.Icon) (sizes []canvas.Texture) {
+	iconExists := func (icon tomo.Icon) bool {
-		small  := icon.Texture(tomo.IconSizeSmall)
+		return icon.Texture(tomo.IconSizeMedium) != nil
-		medium := icon.Texture(tomo.IconSizeMedium)
-		large  := icon.Texture(tomo.IconSizeLarge)
-		if small  != nil { sizes = append(sizes,  small) }
-		if medium != nil { sizes = append(sizes, medium) }
-		if large  != nil { sizes = append(sizes,  large) }
-		return sizes
 	}
 
-	if sizes := allSizes(tomo.Icon(description.ID)); len(sizes) > 0 {
+	if iconExists(tomo.Icon(description.ID)) {
-		window.SetIcon(sizes...)
+		window.SetIcon(tomo.Icon(description.ID))
 		return
 	}
-	if sizes := allSizes(description.Role.Icon()); len(sizes) > 0 {
+	if iconExists(description.Role.Icon()) {
-		window.SetIcon(sizes...)
+		window.SetIcon(description.Role.Icon())
 		return
 	}
 }

config/README.md

@@ -0,0 +1,78 @@
+# config
+Package config provides a configuration system for applications.
+
+## Config File Location
+Config files are stored in standard operating system locations. Each application
+has exactly one user-level config directory within the user-level config
+location, and a system-level subdirectory in each of the system-level config
+locations (if applicable). Each subdirectory bears the application's well-known
+name as specified in ApplicationDescription. Each subdirectory contains a file
+called config.conf, which is where the actual config data is stored.
+
+The user-level configuration file takes precendence over system configuration
+files, and system configuration files take precedence over eachother depending
+on what order they are specified in. How they are specified depends on the
+operating system.
+
+### Linux, Most Unixes
+In terms of the XDG Base Directory Specification, an application with the
+well-known name com.example.Example would have its config files stored at
+`$XDG_CONFIG_DIRS/com.example.Example/config.conf`. On most systems where this
+specification is applicable, this will result in a file at
+`/etc/xdg/com.example.Example/config.conf` and another at
+`$HOME/.config/com.example.Example/config.conf`. The location for config files
+on systems that do not make use of this specification is yet to be determined.
+
+## Config File Format
+The general format of the file is as follows:
+
+- Encoded in UTF-8
+- Consists of lines, separated by \n, or \r\n
+- Lines can be any of these:
+  - Blank line: has only whitespace
+  - Comment: begins with a '#'
+  - Entry: a key/value pair separated by an '=' sign
+
+### Entries
+For entries, all whitespace on either side of the '=' sign, the key, or the
+value is ignored. The key may contain any letter or digit, as well as '-' and
+'.'. The value is always identified by its first rune (after the preliminary
+whitespace of course) and can be one of:
+
+- String
+- Number
+- Bool
+
+#### String
+A string can be either double-quoted, or any string of runes not identifiable
+as any other kind of value. Quoted strings are always unquoted when they are
+read. Either way, these escape sequences are supported, and resolved when they
+are read:
+
+- '\\\\': a literal backslash
+- '\a': alert, bell
+- '\b': backspace
+- '\t': horizontal tab
+- '\n': line feed
+- '\v': vertical tab
+- '\f': form feed
+- '\r': carriage return
+- '\\"': double quote
+
+Be aware that some unquoted strings, within reason, are subject to being read
+as some other value in the future. For example, if there were suddenly a
+third boolean value called glorble, the unquoted string glorble would be read
+as a boolean value instead of a string.
+
+#### Number
+A number is a floating point value. It can be of the form:
+- Inf: positive infinity
+- -Inf: negative infinity
+- NaN: "not a number"
+- [0-9]+: a whole number
+- [0-9]+\.[0-9]*: a fractional number
+
+#### Bool
+A bool is a boolean value. It can be one of:
+- true
+- false

config/config.go

@@ -0,0 +1,159 @@
+// Package config provides a configuration system for applications.
+package config
+
+import "fmt"
+import "math"
+import "strconv"
+import "git.tebibyte.media/tomo/tomo/event"
+
+type configError string;
+func (err configError) Error () string { return string(err) }
+
+const (
+	// ErrClosed is returned when Get/Set/Reset is called after the config
+	// has been closed.
+	ErrClosed = configError("attempt to access a closed config")
+	// ErrNonexistentEntry is returned when an entry was not found.
+	ErrNonexistentEntry = configError("nonexistent entry")
+	// ErrMalformedEntry is returned when a config entry could not be
+	// parsed.
+	ErrMalformedEntry = configError("malformed entry")
+	// ErrMalformedKey is returned when a key has invalid runes.
+	ErrMalformedKey = configError("malformed key")
+	// ErrMalformedValue is returned when a value could not be parsed.
+	ErrMalformedValue = configError("malformed value")
+	// ErrMalformedString is returned when a string value could not be
+	// parsed.
+	ErrMalformedStringValue = configError("malformed string value")
+	// ErrMalformedNumber is returned when a number value could not be
+	// parsed.
+	ErrMalformedNumberValue = configError("malformed number value")
+	// ErrMalformedBool is returned when a boolean value could not be
+	// parsed.
+	ErrMalformedBoolValue = configError("malformed bool value")
+	// ErrMalformedEscapeSequence us returned when an escape sequence could
+	// not be parsed.
+	ErrMalformedEscapeSequence = configError("malformed escape sequence")
+)
+
+// Config provides access to an application's configuration, and can notify an
+// application of changes to it.
+type Config interface {
+	// Get gets a value, first considering the user-level config file, and
+	// then falling back to system level config files. If the value could
+	// not be found anywhere, the specified fallback value is returned. If
+	// the key is invalid, it returns nil, ErrMalformedKey.
+	Get (key string, fallback Value) (Value, error)
+	// GetString is like Get, but will only return strings. If the value is
+	// not a string, it will return fallback.
+	GetString (key string, fallback string) (string, error)
+	// GetNumber is like Get, but will only return numbers. If the value is
+	// not a number, it will return fallback.
+	GetNumber (key string, fallback float64) (float64, error)
+	// GetBool is like Get, but will only return booleans. If the value is
+	// not a boolean, it will return fallback.
+	GetBool (key string, fallback bool) (bool, error)
+	// Set sets a value in the user-level config file. If the key is
+	// invalid, it returns ErrMalformedKey. Note that calling this behavior
+	// *will* cause a write to disk, and a read from disk for whatever is
+	// watching the user file.
+	Set (key string, value Value) error
+	// Reset removes the value from the user-level config file, resetting it
+	// to what is described by the system-level config files. If the key is
+	// invalid, it returns ErrMalformedKey. Note that calling this behavior
+	// *will* cause a write to disk if successful , and a read from disk for
+	// whatever is watching the user file.
+	Reset (key string) error
+	// OnChange specifies a function to be called whenever a value is
+	// changed. The callback is always run within the backend's event loop
+	// using tomo.Do. This could have been a channel but I didn't want to do
+	// that to people.
+	OnChange (func (key string)) event.Cookie
+}
+
+// ConfigCloser is a config with a Close behavior, which stops watching the
+// config file and causes any subsequent sets/gets to return errors. Anything
+// that receives a ConfigCloser must close it when done.
+type ConfigCloser interface {
+	Config
+	// Close closes the config, causing it to stop watching for changes.
+	// Reads or writes to the config after this will return an error.
+	Close () error
+}
+
+var negativeZero = math.Copysign(0, -1)
+
+// Value is a config value. Its String behavior produces a lossless and
+// syntactically valid representation of the value.
+type Value interface {
+	value ()
+	fmt.Stringer
+	Equals (Value) bool
+}
+
+// ValueString is a string value.
+type ValueString string
+var _ Value = ValueString("")
+func (ValueString) value () { }
+func (value ValueString) Equals (other Value) bool {
+	other, ok := other.(ValueString)
+	return ok && value == other
+}
+func (value ValueString) String () string {
+	return fmt.Sprintf("\"%s\"", escape(string(value)))
+}
+
+// ValueNumber is a number value.
+type ValueNumber float64
+var _ Value = ValueNumber(0)
+func (ValueNumber) value () { }
+func (value ValueNumber) Equals (other Value) bool {
+	other, ok := other.(ValueNumber)
+	return ok && value == other
+}
+func (value ValueNumber) String () string {
+	number := float64(value)
+	// the requirements I wrote said lossless in all cases. here's lossless
+	// in all cases!
+	switch {
+	case math.IsInf(number, 0):
+		if math.Signbit(number) {
+			return "-Inf"
+		} else {
+			return "Inf"
+		}
+		
+	case math.IsNaN(number):
+		return "NaN"
+		
+	case number == 0, number == negativeZero:
+		if math.Signbit(number) {
+			return "-0"
+		} else {
+			return "0"
+		}
+		
+	case math.Round(number) == number:
+		return strconv.FormatInt(int64(number), 10)
+		
+	default:
+		return strconv.FormatFloat(number, 'f', -1, 64)
+	}
+}
+
+
+// ValueBool is a boolean value.
+var _ Value = ValueBool(false)
+type ValueBool bool
+func (ValueBool) value () { }
+func (value ValueBool) Equals (other Value) bool {
+	other, ok := other.(ValueBool)
+	return ok && value == other
+}
+func (value ValueBool) String () string {
+	if value {
+		return "true"
+	} else {
+		return "false"
+	}
+}

config/escape.go

@@ -0,0 +1,97 @@
+package config
+
+import "fmt"
+import "strings"
+// import "unicode"
+
+var escapeCodeToRune = map[rune] rune {
+	'\\': '\\',
+	'a':  '\a',
+	'b':  '\b',
+	't':  '\t',
+	'n':  '\n',
+	'v':  '\v',
+	'f':  '\f',
+	'r':  '\r',
+	'"':  '"',
+}
+
+var runeToEscapeCode = map[rune] rune { }
+func init () {
+	for code, char := range escapeCodeToRune {
+		runeToEscapeCode[char] = code
+	}
+}
+
+func escape (str string) string {
+	builder := strings.Builder { }
+	for _, char := range str {
+		code, escaped := runeToEscapeCode[char]
+		switch {
+		case escaped:
+			fmt.Fprintf(&builder, "\\%c", code)
+		// case !unicode.IsPrint(char):
+			// fmt.Fprintf(&builder, "\\%o", char)
+		default:
+			builder.WriteRune(char)
+		}
+	}
+	return builder.String()
+}
+
+func unescape (str string) (string, bool) {
+	runes := []rune(str)
+	builder := strings.Builder { }
+
+	end := func () bool {
+		return len(runes) < 1
+	}
+	next := func () {
+		if !end() { runes = runes[1:] }
+	}
+	
+	for !end() {
+		if runes[0] == '\\' {
+			if end() { return "", false }
+			next()
+			char, isEscape := escapeCodeToRune[runes[0]]
+			switch {
+			case isEscape:
+				builder.WriteRune(char)
+				next()
+			// case isOctalDigit(runes[0]):
+				// char = 0
+				// for !end() && isOctalDigit(runes[0]) {
+					// char *= 8
+					// char += runes[0] - '0'
+					// next()
+				// }
+				// builder.WriteRune(char)
+			default:
+				return "", false
+			}
+		} else {
+			builder.WriteRune(runes[0])
+			next()
+		}
+	}
+	return builder.String(), true
+}
+
+func unquote (str string) (string, bool) {
+	if len(str) < 2             { return "", false }
+	if firstRune(str)    != '"' { return "", false }
+	if str[len(str) - 1] != '"' { return "", false }
+	return str[1:len(str) - 1], true
+}
+
+func isOctalDigit (char rune) bool {
+	return char >= '0' && char <= '7'
+}
+
+func firstRune (str string) rune {
+	for _, char := range str {
+		return char
+	}
+	return 0
+}

config/escape_test.go

@@ -0,0 +1,22 @@
+package config
+
+import "testing"
+
+func TestEscape (test *testing.T) {
+	expected := `\\\a\bhello\t\n\vworld!\f\r\"`
+	got      := escape("\\\a\bhello\t\n\vworld!\f\r\"")
+	if got != expected {
+		test.Fatalf("expected: [%s]\ngot:[%s]", expected, got)
+	}
+}
+
+func TestUnescape (test *testing.T) {
+	expected := "\\\a\bhello\t\n\vworld!\f\r\""
+	got, ok  := unescape(`\\\a\bhello\t\n\vworld!\f\r\"`)
+	if !ok {
+		test.Fatalf("text could not be unescaped")
+	}
+	if got != expected {
+		test.Fatalf("expected: [%s]\ngot:[%s]", expected, got)
+	}
+}

config/file.go

@@ -0,0 +1,247 @@
+package config
+
+import "io"
+import "fmt"
+import "math"
+import "bufio"
+import "errors"
+import "strconv"
+import "strings"
+import "unicode"
+
+type line any
+type comment string
+type entry struct { key string; value Value }
+
+var _ io.WriterTo = new(File)
+
+// File represents a config file. It preserves the order of the lines, as well
+// as blank lines and comments.
+type File struct {
+	lines []line
+	keys  map[string] int
+}
+
+// NewFile creates a blank file with nothing in it.
+func NewFile () *File {
+	return &File {
+		 keys: make(map[string] int),
+	}
+}
+
+// Parse parses a config file from a reader. This function operates on a
+// best-effort basis: A file will always be returned, and any errors encountered
+// will be joined together. For a description of the format, see the README.md
+// of this package.
+func Parse (reader io.Reader) (*File, error) {
+	file := &File {
+		keys: make(map[string] int),
+	}
+	errs    := []error { }
+	scanner := bufio.NewScanner(reader)
+	
+	for scanner.Scan() {
+		text := strings.TrimSpace(scanner.Text())
+		switch {
+		case text == "",  strings.HasPrefix(text, "#"):
+			file.lines = append(file.lines, comment(text))
+		default:
+			entry, err := parseEntry(text)
+			if err == nil {
+				file.keys[entry.key] = len(file.lines)
+				file.lines = append(file.lines, entry)
+			} else {
+				errs = append (errs, err )
+			}
+		}
+	}
+	errs = append(errs, scanner.Err())
+	return file, errors.Join(errs...)
+}
+
+func parseEntry (str string) (entry, error) {
+	key, value, ok := strings.Cut(str, "=")
+	if !ok { return entry { }, ErrMalformedEntry }
+	
+	key   = strings.TrimSpace(key)
+	if !KeyValid(key) { return entry { }, ErrMalformedKey }
+
+	value = strings.TrimSpace(value)
+	parsedValue, err := ParseValue(value)
+	if err != nil { return entry { }, err }
+	
+	return entry { key: key, value: parsedValue }, nil
+}
+
+// ParseValue parses a value from a string. For any Value v,
+// ParseValue(v.String()) should hold data exactly equal to v. This function
+// does not trim whitespace.
+func ParseValue (str string) (Value, error) {
+	first := firstRune(str)
+	switch {
+	case str == "":
+		return ValueString(""), nil
+	case first == '"':
+		value, ok := unescape(str)
+		if !ok { return nil, ErrMalformedEscapeSequence }
+		value, ok = unquote(value)
+		if !ok { return nil, ErrMalformedStringValue }
+		return ValueString(value), nil
+	case first == '-' || (first >= '0' && first <= '9'):
+		value, err := strconv.ParseFloat(str, 64)
+		if err != nil { return nil, ErrMalformedNumberValue }
+		return ValueNumber(value), nil
+	case str == "false":
+		return ValueBool(false), nil
+	case str == "true":
+		return ValueBool(true), nil
+	case str == "Inf":
+		return ValueNumber(math.Inf(1)), nil
+	case str == "NaN":
+		return ValueNumber(math.NaN()), nil
+	default:
+		value, ok := unescape(str)
+		if !ok { return nil, ErrMalformedEscapeSequence }
+		return ValueString(value), nil
+	}
+}
+
+// Has returns whether the key exists. If the key is invalid, it returns false,
+// ErrMalformedKey.
+func (this *File) Has (key string) (bool, error) {
+	if !KeyValid(key) { return false, ErrMalformedKey }
+	if index, ok := this.keys[key]; ok {
+		if _, ok := this.lines[index].(entry); ok {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
+// Get gets the keyed value. If the value is unspecified, it returns nil,
+// ErrNonexistentEntry. If the key is invalid, it returns nil, ErrMalformedKey.
+func (this *File) Get (key string) (Value, error) {
+	if !KeyValid(key) { return nil, ErrMalformedKey }
+	if index, ok := this.keys[key]; ok {
+		if lin, ok := this.lines[index].(entry); ok {
+			return lin.value, nil
+		}
+	}
+	return nil, ErrNonexistentEntry
+}
+
+// Set sets a value. If the key is invalid, it returns ErrMalformedKey.
+func (this *File) Set (key string, value Value) error {
+	if !KeyValid(key) { return ErrMalformedKey }
+	ent := entry {
+		key:   key,
+		value: value,
+	}
+	if index, ok := this.keys[key]; ok {
+		this.lines[index] = ent
+		return nil
+	}
+	this.keys[key] = len(this.lines)
+	this.lines     = append(this.lines, ent)
+	return nil
+}
+
+// Reset removes the value from the file. If the value is set again, it will be
+// added back at the same location. Note that because of this, the positions of
+// lines are not forgotten until the file is written and reloaded. This is why
+// the method is called Reset and not Remove. If the key is invalid, it returns
+// ErrMalformedKey.
+func (this *File) Reset (key string) error {
+	if !KeyValid(key) { return ErrMalformedKey }
+	for index, lin := range this.lines {
+		if lin, ok := lin.(entry); ok {
+			if lin.key == key {
+				this.lines[index] = nil
+			}
+		}
+	}
+	return nil
+}
+
+// Map creates and returns a map of keys to values.
+func (this *File) Map () map[string] Value {
+	mp := make(map[string] Value)
+	for key, index := range this.keys {
+		if lin, ok := this.lines[index].(entry); ok {
+			mp[key] = lin.value
+		}
+	}
+	return mp
+}
+
+// Diff returns a set of keys that are different from the other file.
+func (this *File) Diff (other *File) map[string] struct { } {
+	diff := make(map[string] struct { })
+	
+	// - keys only we have
+	// - keys we both have, but are different
+	for key, index := range this.keys {
+		thisEntry, ok := this.lines[index].(entry)
+		if !ok { continue }
+	
+		otherIndex, ok := other.keys[key]
+		if !ok {
+			diff[key] = struct { } { }
+			continue
+		}
+		otherEntry, ok := other.lines[otherIndex].(entry)
+		if !ok {
+			diff[key] = struct { } { }
+			continue
+		}
+		
+		if !thisEntry.value.Equals(otherEntry.value) {
+			diff[key] = struct { } { }
+		}
+	}
+
+	// - keys only they have
+	for key := range other.keys {
+		if otherHas, _ := other.Has(key); !otherHas {
+			continue
+		}
+		if thisHas, _ := this.Has(key); !thisHas {
+			diff[key] = struct { } { }
+		}
+	}
+
+	return diff
+}
+
+// WriteTo writes the data in this file to an io.Writer.
+func (this *File) WriteTo (writer io.Writer) (n int64, err error) {
+	for _, lin := range this.lines {
+		nint := 0
+		switch lin := lin.(type) {
+		case comment:
+			nint, err = fmt.Fprintln(writer, string(lin))
+		case entry:
+			nint, err = fmt.Fprintf(writer, "%s=%v\n", lin.key, lin.value)
+		}
+		n += int64(nint)
+		if err != nil { return n, err }
+	}
+	return n, nil
+}
+
+// KeyValid returns whether a key contains only valid runes. They are:
+//   - Letters
+//   - Digits
+//   - '-'
+//   - '.'
+func KeyValid (key string) bool {
+	for _, char := range key {
+		valid :=
+			char == '.' ||
+			char == '-' ||
+			unicode.IsLetter(char) ||
+			unicode.IsDigit(char)
+		if !valid { return false }
+	}
+	return true
+}

config/file_test.go

@@ -0,0 +1,222 @@
+package config
+
+import "math"
+import "maps"
+import "strings"
+import "testing"
+
+func TestParseEntryUnquotedString (test *testing.T) {
+	testParseEntry(test, "stringValue = Unquoted\\nString", "stringValue", ValueString("Unquoted\nString"))
+}
+
+func TestParseEntryQuotedString (test *testing.T) {
+	testParseEntry(test, "stringValue = \"Quoted\\nString\"", "stringValue", ValueString("Quoted\nString"))
+}
+
+func TestParseEntryNumber (test *testing.T) {
+	testParseEntry(test, "numberValue = -349.29034", "numberValue", ValueNumber(-349.29034))
+}
+
+func TestParseEntryNumberInf (test *testing.T) {
+	testParseEntry(test, "numberValue = Inf", "numberValue", ValueNumber(math.Inf(1)))
+}
+
+func TestParseEntryNumberNegativeInf (test *testing.T) {
+	testParseEntry(test, "numberValue = -Inf", "numberValue", ValueNumber(math.Inf(-1)))
+}
+
+func TestParseEntryNumberNaN (test *testing.T) {
+	testParseEntry(test, "numberValue = NaN", "numberValue", ValueNumber(math.NaN()))
+}
+
+func TestParseEntryBoolTrue (test *testing.T) {
+	testParseEntry(test, "boolValue = true", "boolValue", ValueBool(true))
+}
+
+func TestParseEntryBoolFalse (test *testing.T) {
+	testParseEntry(test, "boolValue = false", "boolValue", ValueBool(false))
+}
+
+func TestParseEntryComplexKey (test *testing.T) {
+	testParseEntry (
+		test, "--Something.OtherThing...another-Thing-=value",
+		"--Something.OtherThing...another-Thing-", ValueString("value"))
+}
+
+func TestParse (test *testing.T) {
+testParse(test,
+`  thing  =something
+# comment
+
+   otherThing   = otherValue
+   otherThing = otherValue1
+   otherThing = otherValue2 # not a comment
+`,
+`thing="something"
+# comment
+
+otherThing="otherValue"
+otherThing="otherValue1"
+otherThing="otherValue2 # not a comment"
+`)
+}
+
+func TestGetValue (test *testing.T) {
+	file := parseFileString(test,
+`key=askdhj
+# some comment
+key = value
+key1 = 7`)
+	got, err := file.Get("key")
+	if err != nil { test.Fatal(err) }
+	testValueString(test, got, `"value"`)
+}
+
+func TestModifyValue (test *testing.T) {
+	file := parseFileString(test,
+`key=askdhj
+# some comment
+key = value
+key1 = 7`)
+	err := file.Set("key", ValueNumber(324980.2349))
+	if err != nil { test.Fatal(err) }
+	testFileString(test, file,
+`key="askdhj"
+# some comment
+key=324980.2349
+key1=7
+`)
+}
+
+func TestResetValue (test *testing.T) {
+	file := parseFileString(test,
+`key=askdhj
+# some comment
+key = value
+
+key1 = 7`)
+	err := file.Reset("key")
+	if err != nil { test.Fatal(err) }
+	testFileString(test, file,
+`# some comment
+
+key1=7
+`)
+}
+
+func TestDiffNone (test *testing.T) {
+	str := `
+thing = something
+
+otherThing  = otherValue
+# comment
+otherThing = true
+otherThing = 234
+
+yetAnotherThing = 0.23498
+`
+	file1 := parseFileString(test, str)
+	file2 := parseFileString(test, str)
+	diff := file1.Diff(file2)
+	if len(diff) != 0 {
+		test.Fatalf("diff not empty:\n%v", diff)
+	}
+}
+
+func TestDiffReset (test *testing.T) {
+	file1 := parseFileString(test,
+`key4=0
+key1=value1
+keyToDelete=true
+# comment
+key2=34`)
+	file2 := parseFileString(test,
+`key1=value2
+key2=34
+anotherKeyToDelete=false
+# comment
+
+key3=0.2`)
+	file1.Reset("keyToDelete")
+	file2.Reset("anotherKeyToDelete")
+	diff := file1.Diff(file2)
+	correct := map[string] struct { } {
+		"key1": struct { } { },
+		"key3": struct { } { },
+		"key4": struct { } { },
+	}
+	if !maps.Equal(diff, correct) {
+		test.Error("diffs do not match")
+		test.Errorf("EXPECTED:\n%v", correct)
+		test.Errorf("GOT:\n%v", diff)
+		test.Fail()
+	}
+}
+
+func TestDiff (test *testing.T) {
+	file1 := parseFileString(test,
+`key4=0
+key1=value1
+# comment
+key2=34`)
+	file2 := parseFileString(test,
+`key1=value2
+key2=34
+# comment
+
+key3=0.2`)
+	diff := file1.Diff(file2)
+	correct := map[string] struct { } {
+		"key1": struct { } { },
+		"key3": struct { } { },
+		"key4": struct { } { },
+	}
+	if !maps.Equal(diff, correct) {
+		test.Error("diffs do not match")
+		test.Errorf("EXPECTED:\n%v", correct)
+		test.Errorf("GOT:\n%v", diff)
+		test.Fail()
+	}
+}
+
+func testParseEntry (test *testing.T, str string, key string, value Value) {
+	ent, err := parseEntry(str)
+	if err != nil { test.Fatal(err) }
+	if ent.key != key {
+		test.Fatalf("expected key: [%s]\ngot key: [%s]", key, ent.key)
+	}
+	if ent.value.String() != value.String() {
+		test.Fatalf("expected value: [%s]\ngot value: [%s]", value.String(), ent.value.String())
+	}
+}
+
+func testParse (test *testing.T, str, correct string) {
+	if correct == "" { correct = str }
+	testFileString(test, parseFileString(test, str), correct)
+}
+
+func parseFileString (test *testing.T, str string) *File {
+	file, err := Parse(strings.NewReader(str))
+	if err != nil { test.Fatal(err) }
+	return file
+}
+
+func testFileString (test *testing.T, file *File, correct string) {
+	got := strings.Builder { }
+	file.WriteTo(&got)
+	if got.String() != correct {
+		test.Error("strings do not match")
+		test.Errorf("EXPECTED:\n%s", correct)
+		test.Errorf("GOT:\n%s", got.String())
+		test.Fail()
+	}
+}
+
+func testValueString (test *testing.T, got Value, correct string) {
+	if got.String() != correct {
+		test.Error("strings do not match")
+		test.Errorf("EXPECTED:\n%s", correct)
+		test.Errorf("GOT:\n%s", got.String())
+		test.Fail()
+	}
+}

config/impl.go

@@ -0,0 +1,318 @@
+package config
+
+import "os"
+import "log"
+import "sync"
+import "slices"
+import "path/filepath"
+import "github.com/fsnotify/fsnotify"
+import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/event"
+
+// Goroutine model:
+// All private methods (except for lockAndProcessEvent) do not lock the config,
+// but all public methods do. Private methods may not call public methods.
+// Locking must always be method-level, with a call to Lock at the start,
+// directly followed by a deferred call to Unlock.
+
+type config struct {
+	open                 bool
+	watcher              *fsnotify.Watcher
+	lock                 sync.RWMutex
+	ignoreNextUserUpdate bool
+
+	paths struct {
+		user     string
+		system   []string
+		watching map[string] struct { }
+	}
+
+	data struct {
+		user   *File
+		system []map[string] Value
+	}
+	
+	on struct {
+		change event.Broadcaster[func (string)]
+	}
+}
+
+// NewConfig creates a new Config using paths to the user-level config file, and
+// a set of system config files. These files need not exist: the user-level file
+// will be created when Set is called for the first time if it does not exist
+// already, and nonexistent system files are simply ignored (unless the Config
+// finds them at any point to have been spontaneously created).
+//
+// The user file is written to when Set is called, and the system files are only
+// read from. Values in the user file override those in the system files, and
+// system files specified nearer to the start of the vararg list will override
+// those farther down.
+func NewConfig (user string, system ...string) (ConfigCloser, error) {
+	conf := new(config)
+	conf.paths.user   = user
+	conf.paths.system = system
+	err := conf.init()
+	if err != nil { return nil, err }
+	go func () {
+		for event := range conf.watcher.Events {
+			conf.lockAndProcessEvent(event)
+		}
+	} ()
+	return conf, nil
+}
+
+// this method may only be run in the goroutine spawned by NewConfig.
+func (this *config) lockAndProcessEvent (event fsnotify.Event) {
+	this.lock.Lock()
+	defer this.lock.Unlock()
+	if !(event.Has(fsnotify.Write))                  { return }
+	if _, ok := this.paths.watching[event.Name]; !ok { return }
+
+	if event.Name == this.paths.user {
+		if !this.ignoreNextUserUpdate {
+			previousUser := this.data.user
+			this.reloadUser()
+			newUser := this.data.user
+			this.processUserDiff(newUser.Diff(previousUser))
+		}
+		this.ignoreNextUserUpdate = false
+	} else {
+		index := slices.Index(this.paths.system, event.Name)
+		if index > 0 {
+			previousSystem := this.data.system[index]
+			this.reloadSystem(index)
+			newSystem := this.data.system[index]
+			this.processSystemDiff(index, diffValueMaps(newSystem, previousSystem))
+		}
+	}
+}
+
+func (this *config) init () error {
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil { return err }
+	this.watcher = watcher
+	
+	this.paths.watching = make(map[string] struct { })
+	this.watcher.Add(filepath.Dir(this.paths.user))
+	this.paths.watching[this.paths.user] = struct { } { }
+	this.reloadUser()
+	for index, path := range this.paths.system {
+		this.watcher.Add(filepath.Dir(path))
+		this.paths.watching[path] = struct { } { }
+		this.reloadSystem(index)
+	}
+
+	return nil
+}
+
+func (this *config) errIfClosed () error {
+	if this.open {
+		return nil
+	} else {
+		return ErrClosed
+	}
+}
+
+func (this *config) reloadUser () {
+	file, err := os.Open(this.paths.user)
+	if err != nil { return }
+	defer file.Close()
+	
+	userFile, err := Parse(file)
+	if err != nil {
+		log.Printf("nasin: problems loading user config file %s: %v", this.paths.user, err)
+		return
+	}
+	this.data.user = userFile
+}
+
+func (this *config) reloadSystem (index int) {
+	path := this.paths.system[index]
+	file, err := os.Open(path)
+	if err != nil { return }
+	defer file.Close()
+	
+	systemFile, err := Parse(file)
+	if err != nil {
+		log.Printf("nasin: problems loading system config file %s: %v", path, err)
+		return
+	}
+	this.data.system[index] = systemFile.Map()
+}
+
+func (this *config) saveUser () error {
+	// TODO set some sort of flag to ignore the next inotify event for the
+	// user file so we dont reload it immediately after. also need to
+	// broadacast Changed event.
+	enclosingDir := filepath.Dir(this.paths.user)
+	err := os.MkdirAll(enclosingDir, 755)
+	if err != nil { return err }
+	file, err := os.Create(this.paths.user)
+	if err != nil { return err }
+	defer file.Close()
+	_, err = this.data.user.WriteTo(file)
+	if err != nil { return err }
+	this.ignoreNextUserUpdate = true
+	return nil
+}
+
+func (this *config) processUserDiff (changed map[string] struct { }) {
+	for key := range changed {
+		// this is the user file, and nothing has precedence over it, so
+		// the change always matters
+		this.broadcastChange(key)
+	}
+}
+
+func (this *config) processSystemDiff (index int, changed map[string] struct { }) {
+	for key := range changed {
+		// if specified in the user file, the change doesn't matter
+		if this.data.user != nil {
+			if has, _ := this.data.user.Has(key); has {
+				continue
+			}
+		}
+		
+		// if specified in any system files with precedence greater than
+		// this one, the change doesn't matter
+		for _, system := range this.data.system[:index] {
+			if _, has := system[key]; has {
+				continue
+			}
+		}
+
+		// the change does matter
+		this.broadcastChange(key)
+	}
+}
+
+func (this *config) broadcastChange (key string) {
+	for _, listener := range this.on.change.Listeners() {
+		tomo.Do(func () { listener(key) })
+	}
+}
+
+func (this *config) get (key string, fallback Value) (Value, error) {
+	// try user config
+	if !KeyValid(key) { return nil, ErrMalformedKey }
+
+	if this.data.user != nil {
+		value, err := this.data.user.Get(key)
+		if err == nil && err != ErrNonexistentEntry {
+			return value, nil
+		}
+	}
+
+	// try system configs
+	for _, config := range this.data.system {
+		if value, ok := config[key]; ok {
+			return value, nil
+		}
+	}
+
+	// use fallback
+	return fallback, nil
+	
+}
+
+func (this *config) Get (key string, fallback Value) (Value, error) {
+	this.lock.Lock()
+	defer this.lock.Unlock()
+	return this.get(key, fallback)
+}
+
+func (this *config) Close () error {
+	this.lock.Lock()
+	defer this.lock.Unlock()
+	this.open = false
+	return this.watcher.Close()
+}
+
+func (this *config) GetString (key string, fallback string) (string, error) {
+	this.lock.Lock()
+	defer this.lock.Unlock()
+	value, err := this.get(key, ValueString(fallback))
+	if err != nil { return "", err }
+	if value, ok := value.(ValueString); ok {
+		return string(value), nil
+	}
+	return fallback, nil
+}
+
+func (this *config) GetNumber (key string, fallback float64) (float64, error) {
+	this.lock.Lock()
+	defer this.lock.Unlock()
+	value, err := this.get(key, ValueNumber(fallback))
+	if err != nil { return 0, err }
+	if value, ok := value.(ValueNumber); ok {
+		return float64(value), nil
+	}
+	return fallback, nil
+}
+
+func (this *config) GetBool (key string, fallback bool) (bool, error) {
+	this.lock.Lock()
+	defer this.lock.Unlock()
+	value, err := this.get(key, ValueBool(fallback))
+	if err != nil { return false, err }
+	if value, ok := value.(ValueBool); ok {
+		return bool(value), nil
+	}
+	return fallback, nil
+}
+
+func (this *config) Set (key string, value Value) error {
+	this.lock.Lock()
+	defer this.lock.Unlock()
+	if this.data.user == nil { this.data.user = NewFile() }
+	err := this.data.user.Set(key, value)
+	if err != nil { return err }
+	err = this.saveUser()
+	if err != nil { return err }
+	this.broadcastChange(key)
+	return nil
+}
+
+func (this *config) Reset (key string) error {
+	this.lock.Lock()
+	defer this.lock.Unlock()
+	if this.data.user == nil { this.data.user = NewFile() }
+	err := this.data.user.Reset(key)
+	if err != nil { return err }
+	err = this.saveUser()
+	if err != nil { return err }
+	this.broadcastChange(key)
+	return nil
+}
+
+func (this *config) OnChange (callback func (string)) event.Cookie {
+	this.lock.Lock()
+	defer this.lock.Unlock()
+	return this.on.change.Connect(callback)
+}
+
+func diffValueMaps (first, second map[string] Value) map[string] struct { } {
+	diff := make(map[string] struct { })
+	
+	// - keys only first has
+	// - keys both have, but are different
+	for key, firstValue := range first {
+		secondValue, ok := second[key]
+		if !ok {
+			diff[key] = struct { } { }
+			continue
+		}
+		if !firstValue.Equals(secondValue) {
+			diff[key] = struct { } { }
+		}
+	}
+
+	// - keys only second has
+	for key := range second {
+		if _, has := first[key]; !has {
+			diff[key] = struct { } { }
+		}
+	}
+
+	return diff
+}

config/impl_test.go

@@ -0,0 +1,53 @@
+package config
+
+import "maps"
+import "testing"
+
+func TestDiffValueMapsNone (test *testing.T) {
+	str := `
+thing = something
+
+otherThing  = otherValue
+# comment
+otherThing = true
+otherThing = 234
+
+yetAnotherThing = 0.23498
+`
+	file1 := parseFileString(test, str)
+	file2 := parseFileString(test, str)
+	diff := diffValueMaps(file1.Map(), file2.Map())
+	if len(diff) != 0 {
+		test.Fatalf("diff not empty:\n%v", diff)
+	}
+}
+
+func TestDiffValueMaps (test *testing.T) {
+	file1 := parseFileString(test,
+`key4=0
+key1=value1
+# comment
+key2=34`)
+	file2 := parseFileString(test,
+`key1=value2
+key2=34
+# comment
+
+key3=0.2`)
+	diff := diffValueMaps(file1.Map(), file2.Map())
+	correct := map[string] struct { } {
+		"key1": struct { } { },
+		"key3": struct { } { },
+		"key4": struct { } { },
+	}
+	if !maps.Equal(diff, correct) {
+		test.Error("diffs do not match")
+		test.Errorf("EXPECTED:\n%v", correct)
+		test.Errorf("GOT:\n%v", diff)
+		test.Fail()
+	}
+}
+
+// TODO we need way more tests!
+// need to test watching files. maybe make a temp dir and do it there. remember
+// to defer cleaning up the dir and closing of the config.

go.mod

@@ -1,12 +1,14 @@
 module git.tebibyte.media/tomo/nasin
 
-go 1.20
+go 1.22.2
 
 require (
-	git.tebibyte.media/tomo/backend v0.5.0
+	git.tebibyte.media/sashakoshka/goparse v0.2.0
-	git.tebibyte.media/tomo/objects v0.20.0
+	git.tebibyte.media/tomo/backend v0.7.0
-	git.tebibyte.media/tomo/tomo v0.41.0
+	git.tebibyte.media/tomo/objects v0.22.0
+	git.tebibyte.media/tomo/tomo v0.46.1
 	git.tebibyte.media/tomo/xdg v0.1.0
+	github.com/fsnotify/fsnotify v1.7.0
 	golang.org/x/image v0.11.0
 )
 
@@ -17,4 +19,5 @@ require (
 	github.com/BurntSushi/graphics-go v0.0.0-20160129215708-b43f31a4a966 // indirect
 	github.com/jezek/xgb v1.1.1 // indirect
 	github.com/jezek/xgbutil v0.0.0-20231116234834-47f30c120111 // indirect
+	golang.org/x/sys v0.5.0 // indirect
 )

go.sum

@@ -1,10 +1,12 @@
+git.tebibyte.media/sashakoshka/goparse v0.2.0 h1:uQmKvOCV2AOlCHEDjg9uclZCXQZzq2PxaXfZ1aIMiQI=
+git.tebibyte.media/sashakoshka/goparse v0.2.0/go.mod h1:tSQwfuD+EujRoKr6Y1oaRy74ZynatzkRLxjE3sbpCmk=
 git.tebibyte.media/sashakoshka/xgbkb v1.0.0/go.mod h1:pNcE6TRO93vHd6q42SdwLSTTj25L0Yzggz7yLe0JV6Q=
-git.tebibyte.media/tomo/backend v0.5.0 h1:Byrz1yjhYKnMXljIHgEdwW5/41gWtRm3xHYZ18lBUbg=
+git.tebibyte.media/tomo/backend v0.7.0 h1:12A+IsbwIKCmg4jKjD9xCDz+o7R3X6Yp8cZup+wOGIM=
-git.tebibyte.media/tomo/backend v0.5.0/go.mod h1:1Ne0h4nsRYy8GudBia7um+qaqzME0wDrOAjpHvySqRA=
+git.tebibyte.media/tomo/backend v0.7.0/go.mod h1:G3Kh6N2MuiAwsnuPe3h9CwWL65vmmsaqgapA38MPyhk=
-git.tebibyte.media/tomo/objects v0.20.0 h1:HK6aWxBfRe0sgqvfIZnvfW0c8jSYP7F5Od/rWvi5DAM=
+git.tebibyte.media/tomo/objects v0.22.0 h1:2t21W32HW2xvPBICqmArVMVWxg9ohhTJw6ChZ0DcdYY=
-git.tebibyte.media/tomo/objects v0.20.0/go.mod h1:DNTKSU9u126XF4usZG0ax9b20So4UpBZ+wAwRiA7XOQ=
+git.tebibyte.media/tomo/objects v0.22.0/go.mod h1:f5J5tAhO+eN5glVbCJLPSopIeTylXqLgKLVAIg8iAPQ=
-git.tebibyte.media/tomo/tomo v0.41.0 h1:Z+7FHhbGiKjs+kQNvuJOfz47xIct5qxvSJqyDuoNIOs=
+git.tebibyte.media/tomo/tomo v0.46.1 h1:/8fT6I9l4TK529zokrThbNDHGRvUsNgif1Zs++0PBSQ=
-git.tebibyte.media/tomo/tomo v0.41.0/go.mod h1:C9EzepS9wjkTJjnZaPBh22YvVPyA4hbBAJVU20Rdmps=
+git.tebibyte.media/tomo/tomo v0.46.1/go.mod h1:WrtilgKB1y8O2Yu7X4mYcRiqOlPR8NuUnoA/ynkQWrs=
 git.tebibyte.media/tomo/typeset v0.7.1 h1:aZrsHwCG5ZB4f5CruRFsxLv5ezJUCFUFsQJJso2sXQ8=
 git.tebibyte.media/tomo/typeset v0.7.1/go.mod h1:PwDpSdBF3l/EzoIsa2ME7QffVVajnTHZN6l3MHEGe1g=
 git.tebibyte.media/tomo/xdg v0.1.0 h1:6G2WYPPiM2IXleCpKKHuJA34BxumwNWuLsUoX3yu5zA=
@@ -15,6 +17,8 @@ github.com/BurntSushi/freetype-go v0.0.0-20160129220410-b763ddbfe298 h1:1qlsVAQJ
 github.com/BurntSushi/freetype-go v0.0.0-20160129220410-b763ddbfe298/go.mod h1:D+QujdIlUNfa0igpNMk6UIvlb6C252URs4yupRUV4lQ=
 github.com/BurntSushi/graphics-go v0.0.0-20160129215708-b43f31a4a966 h1:lTG4HQym5oPKjL7nGs+csTgiDna685ZXjxijkne828g=
 github.com/BurntSushi/graphics-go v0.0.0-20160129215708-b43f31a4a966/go.mod h1:Mid70uvE93zn9wgF92A/r5ixgnvX8Lh68fxp9KQBaI0=
+github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
+github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
 github.com/jezek/xgb v1.1.0/go.mod h1:nrhwO0FX/enq75I7Y7G8iN1ubpSGZEiA3v9e9GyRFlk=
 github.com/jezek/xgb v1.1.1 h1:bE/r8ZZtSv7l9gk6nU0mYx51aXrvnyb44892TwSaqS4=
 github.com/jezek/xgb v1.1.1/go.mod h1:nrhwO0FX/enq75I7Y7G8iN1ubpSGZEiA3v9e9GyRFlk=
@@ -40,6 +44,7 @@ golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.5.0 h1:MUK/U/4lj1t1oPg0HfuXDN/Z1wv31ZJ/YcPiGccS4DU=
 golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=

internal/faces/fallback/face.go

@@ -0,0 +1,35 @@
+package fallbackFaces
+
+import "golang.org/x/image/font"
+import "git.tebibyte.media/tomo/tomo"
+import "golang.org/x/image/font/basicfont"
+import "git.tebibyte.media/tomo/backend/style"
+
+type faceSet struct {
+	regular    font.Face
+	bold       font.Face
+	italic     font.Face
+	boldItalic font.Face
+}
+
+// New creates a new fallback face set.
+func New () style.FaceSet {
+	// TODO maybe pre-generate different variations of this face
+	return &faceSet {
+		regular:    basicfont.Face7x13,
+		bold:       basicfont.Face7x13,
+		italic:     basicfont.Face7x13,
+		boldItalic: basicfont.Face7x13,
+	}
+}
+
+func (this *faceSet) Face (face tomo.Face) font.Face {
+	bold   := face.Weight >= 500
+	italic := face.Italic >= 0.1 || face.Slant >= 0.1
+	switch {
+	case bold && italic: return this.boldItalic
+	case bold:           return this.bold
+	case italic:         return this.italic
+	default:             return this.regular
+	}
+}

internal/icons/fallback/icon.go

@@ -6,14 +6,37 @@ import _ "embed"
 import _ "image/png"
 import "git.tebibyte.media/tomo/tomo"
 import "git.tebibyte.media/tomo/tomo/data"
+import "git.tebibyte.media/tomo/tomo/event"
 import "git.tebibyte.media/tomo/tomo/canvas"
+import "git.tebibyte.media/tomo/backend/style"
+import "git.tebibyte.media/tomo/nasin/internal/util"
 
 //go:embed assets/icons-small.png
 var atlasSmallBytes []byte
 //go:embed assets/icons-large.png
 var atlasLargeBytes []byte
 
-func generateSource (data []byte, width int) map[tomo.Icon] canvas.Texture {
+const (
+	iconApplicationXGeneric    = tomo.Icon("application/x-generic")
+	iconApplicationXExecutable = tomo.Icon("application/x-executable")
+	iconAudioXGeneric          = tomo.Icon("audio/x-generic")
+	iconFontXGeneric           = tomo.Icon("font/x-generic")
+	iconImageXGeneric          = tomo.Icon("image/x-generic")
+	iconModelXGeneric          = tomo.Icon("model/x-generic")
+	iconPackageXGeneric        = tomo.Icon("package/x-generic")
+	iconTextXGeneric           = tomo.Icon("text/x-generic")
+	iconTextHtml               = tomo.Icon("text/html")
+	iconTextXGenericTemplate   = tomo.Icon("text/x-generic-template")
+	iconTextXScript            = tomo.Icon("text/x-script")
+	iconVideoXGeneric          = tomo.Icon("video/x-generic")
+	iconXOfficeAddressBook     = tomo.Icon("x-office-address-book")
+	iconXOfficeCalendar        = tomo.Icon("x-office-calendar")
+	iconXOfficeDocument        = tomo.Icon("x-office-document")
+	iconXOfficePresentation    = tomo.Icon("x-office-presentation")
+	iconXOfficeSpreadsheet     = tomo.Icon("x-office-spreadsheet")
+)
+
+func generateSource (data []byte, width int) (canvas.TextureCloser, map[tomo.Icon] canvas.Texture) {
 	atlasImage, _, err := image.Decode(bytes.NewReader(data))
 	if err != nil { panic(err) }
 	atlasTexture := tomo.NewTexture(atlasImage)
@@ -36,7 +59,23 @@ func generateSource (data []byte, width int) map[tomo.Icon] canvas.Texture {
 	}
 
 	col(tomo.IconUnknown)
-	col(tomo.Icon("File"))
+	col(iconApplicationXGeneric)
+	col(iconApplicationXExecutable)
+	col(iconAudioXGeneric)
+	col(iconFontXGeneric)
+	col(iconImageXGeneric)
+	col(iconModelXGeneric)
+	col(iconPackageXGeneric)
+	col(iconTextXGeneric)
+	col(iconTextHtml)
+	col(iconTextXGenericTemplate)
+	col(iconTextXScript)
+	col(iconVideoXGeneric)
+	col(iconXOfficeAddressBook)
+	col(iconXOfficeCalendar)
+	col(iconXOfficeDocument)
+	col(iconXOfficePresentation)
+	col(iconXOfficeSpreadsheet)
 
 	row()
 	// actions
@@ -110,9 +149,14 @@ func generateSource (data []byte, width int) map[tomo.Icon] canvas.Texture {
 	col(tomo.IconInsertLink)
 	col(tomo.IconInsertObject)
 	col(tomo.IconInsertText)
+
+	row()
 	// actions: list
 	col(tomo.IconListAdd)
 	col(tomo.IconListRemove)
+	col(tomo.IconListChoose)
+	col(tomo.IconListExpand)
+	col(tomo.IconListContract)
 
 	row()
 	// actions: mail
@@ -310,9 +354,6 @@ func generateSource (data []byte, width int) map[tomo.Icon] canvas.Texture {
 	col(tomo.IconPlacePreferences)
 
 	row()
-	// status: checkbox
-	col(tomo.IconCheckboxChecked)
-	col(tomo.IconCheckboxUnchecked)
 	// status: appointments
 	col(tomo.IconAppointmentMissed)
 	col(tomo.IconAppointmentSoon)
@@ -408,26 +449,29 @@ func generateSource (data []byte, width int) map[tomo.Icon] canvas.Texture {
 	col(tomo.IconWeatherSnow)
 	col(tomo.IconWeatherStorm)
 	
-	return source
+	return atlasTexture, source
 }
 
-type iconTheme struct {
+type iconSet struct {
+	atlasSmall canvas.TextureCloser
+	atlasLarge canvas.TextureCloser
 	texturesSmall map[tomo.Icon] canvas.Texture
 	texturesLarge map[tomo.Icon] canvas.Texture
 }
 
-// New creates a new fallback icon theme.
+// New creates a new fallback icon set.
-func New () tomo.IconSet {
+func New () (style.IconSet, event.Cookie) {
-	return new(iconTheme)
+	iconSet := new(iconSet)
+	return iconSet, iconSet
 }
 
-func (this *iconTheme) ensure () {
+func (this *iconSet) ensure () {
 	if this.texturesSmall != nil { return }
-	this.texturesSmall = generateSource(atlasSmallBytes, 16)
+	this.atlasSmall, this.texturesSmall = generateSource(atlasSmallBytes, 16)
-	this.texturesLarge = generateSource(atlasLargeBytes, 32)
+	this.atlasLarge, this.texturesLarge = generateSource(atlasLargeBytes, 32)
 }
 
-func (this *iconTheme) selectSource (size tomo.IconSize) map[tomo.Icon] canvas.Texture {
+func (this *iconSet) selectSource (size tomo.IconSize) map[tomo.Icon] canvas.Texture {
 	if size == tomo.IconSizeSmall {
 		return this.texturesSmall
 	} else {
@@ -435,7 +479,7 @@ func (this *iconTheme) selectSource (size tomo.IconSize) map[tomo.Icon] canvas.T
 	}
 }
 
-func (this *iconTheme) Icon (icon tomo.Icon, size tomo.IconSize) canvas.Texture {
+func (this *iconSet) Icon (icon tomo.Icon, size tomo.IconSize) canvas.Texture {
 	this.ensure()
 	source := this.selectSource(size)
 	if texture, ok := source[icon]; ok {
@@ -444,12 +488,28 @@ func (this *iconTheme) Icon (icon tomo.Icon, size tomo.IconSize) canvas.Texture
 	return nil
 }
 
-func (this *iconTheme) MimeIcon (mime data.Mime, size tomo.IconSize) canvas.Texture {
+func (this *iconSet) MimeIcon (mime data.Mime, size tomo.IconSize) canvas.Texture {
 	this.ensure()
 	source := this.selectSource(size)
+
+	if icon, ok := source[tomo.Icon(mime.String())]; ok {
+		return icon
+	}
+
 	if mime == data.M("inode", "directory") {
 		return source[tomo.IconPlaceDirectory]
+	} else if icon, ok := source[tomo.Icon(util.GeneralizeXDGIconMimeType(mime).String())]; ok {
+		return icon
 	} else {
-		return source[tomo.Icon("File")]
+		return source[tomo.Icon(iconApplicationXGeneric)]
+	}
+}
+
+func (this *iconSet) Close () {
+	if this.atlasSmall != nil {
+		this.atlasSmall.Close()
+	}
+	if this.atlasLarge != nil {
+		this.atlasLarge.Close()
 	}
 }

internal/icons/xdg/icon.go

@@ -8,34 +8,37 @@ import "regexp"
 import "strings"
 import _ "image/png"
 import "git.tebibyte.media/tomo/tomo"
-import xdgIconTheme "git.tebibyte.media/tomo/xdg/icon-theme"
 import "git.tebibyte.media/tomo/tomo/data"
+import "git.tebibyte.media/tomo/tomo/event"
 import "git.tebibyte.media/tomo/tomo/canvas"
+import "git.tebibyte.media/tomo/backend/style"
+import "git.tebibyte.media/tomo/nasin/internal/util"
+import xdgIconTheme "git.tebibyte.media/tomo/xdg/icon-theme"
 
 type iconTheme struct {
 	xdg xdgIconTheme.Theme
-	fallback       tomo.IconSet
+	fallback       style.IconSet
-	texturesSmall  map[tomo.Icon] canvas.Texture
+	texturesSmall  map[tomo.Icon] canvas.TextureCloser
-	texturesMedium map[tomo.Icon] canvas.Texture
+	texturesMedium map[tomo.Icon] canvas.TextureCloser
-	texturesLarge  map[tomo.Icon] canvas.Texture
+	texturesLarge  map[tomo.Icon] canvas.TextureCloser
 }
 
-func FindThemeWarn (name string, fallback tomo.IconSet, path ...string) (tomo.IconSet, error) {
+func FindThemeWarn (name string, fallback style.IconSet, path ...string) (style.IconSet, event.Cookie, error) {
 	this := &iconTheme {
 		fallback:       fallback,
-		texturesLarge:  make(map[tomo.Icon] canvas.Texture),
+		texturesLarge:  make(map[tomo.Icon] canvas.TextureCloser),
-		texturesMedium: make(map[tomo.Icon] canvas.Texture),
+		texturesMedium: make(map[tomo.Icon] canvas.TextureCloser),
-		texturesSmall:  make(map[tomo.Icon] canvas.Texture),
+		texturesSmall:  make(map[tomo.Icon] canvas.TextureCloser),
 	}
 	
 	xdg, err := xdgIconTheme.FindThemeWarn(name, path...)
-	if err != nil { return nil, err }
+	if err != nil { return nil, nil, err }
 	this.xdg = xdg
 	
-	return this, nil
+	return this, this, nil
 }
 
-func (this *iconTheme) selectSource (size tomo.IconSize) map[tomo.Icon] canvas.Texture {
+func (this *iconTheme) selectSource (size tomo.IconSize) map[tomo.Icon] canvas.TextureCloser {
 	switch size {
 	case tomo.IconSizeMedium: return this.texturesMedium
 	case tomo.IconSizeLarge:  return this.texturesLarge
@@ -43,7 +46,7 @@ func (this *iconTheme) selectSource (size tomo.IconSize) map[tomo.Icon] canvas.T
 	}
 }
 
-func (this *iconTheme) xdgIcon (name string, size tomo.IconSize) (canvas.Texture, bool) {
+func (this *iconTheme) xdgIcon (name string, size tomo.IconSize) (canvas.TextureCloser, bool) {
 	// TODO use scaling factor instead of 1
 	// find icon file
 	icon, err := this.xdg.FindIcon(name, iconSizePixels(size), 1, xdgIconTheme.PNG)
@@ -98,7 +101,20 @@ func (this *iconTheme) MimeIcon (mime data.Mime, size tomo.IconSize) canvas.Text
 	}
 }
 
-func (this *iconTheme) icon (icon tomo.Icon, size tomo.IconSize) canvas.Texture {
+func (this *iconTheme) Close () {
+	closeAllIn := func (mp map[tomo.Icon] canvas.TextureCloser) {
+		for _, texture := range mp {
+			if texture != nil {
+				texture.Close()
+			}
+		}
+	}
+	closeAllIn(this.texturesSmall)
+	closeAllIn(this.texturesMedium)
+	closeAllIn(this.texturesLarge)
+}
+
+func (this *iconTheme) icon (icon tomo.Icon, size tomo.IconSize) canvas.TextureCloser {
 	if texture, ok := this.xdgIcon(XdgIconName(icon), size); ok {
 		return texture
 	}
@@ -108,11 +124,11 @@ func (this *iconTheme) icon (icon tomo.Icon, size tomo.IconSize) canvas.Texture
 	return nil
 }
 
-func (this *iconTheme) mimeIcon (mime data.Mime, size tomo.IconSize) canvas.Texture {
+func (this *iconTheme) mimeIcon (mime data.Mime, size tomo.IconSize) canvas.TextureCloser {
 	if texture, ok := this.xdgIcon(xdgFormatMime(mime), size); ok {
 		return texture
 	}
-	if texture, ok := this.xdgIcon(xdgFormatMime(generalizeMimeType(mime)), size); ok {
+	if texture, ok := this.xdgIcon(xdgFormatMime(util.GeneralizeXDGIconMimeType(mime)), size); ok {
 		return texture
 	}
 	if texture, ok := this.xdgIcon(xdgFormatMime(data.M("text", "x-generic")), size); ok {
@@ -165,13 +181,6 @@ func xdgFormatMime (mime data.Mime) string {
 	return fmt.Sprintf("%s-%s", mime.Type, mime.Subtype)
 }
 
-func generalizeMimeType (mime data.Mime) data.Mime {
-	// FIXME make this more accurate
-	// https://specifications.freedesktop.org/icon-naming-spec/icon-naming-spec-latest.html
-	mime.Subtype = "x-generic"
-	return mime
-}
-
 func iconSizePixels (size tomo.IconSize) int {
 	// TODO: once Tomo has scaling support, take that into account here
 	switch size {

internal/registrar/registrar_unix.go

@@ -1,43 +1,82 @@
 //go:build unix && (!darwin)
 package registrar
 
-import "os"
 import "log"
 import "git.tebibyte.media/tomo/tomo"
 import "git.tebibyte.media/tomo/backend/x"
+import "git.tebibyte.media/tomo/tomo/event"
+import "git.tebibyte.media/sashakoshka/goparse"
 import "git.tebibyte.media/tomo/nasin/internal/icons/xdg"
+import "git.tebibyte.media/tomo/nasin/internal/styles/tss"
 import "git.tebibyte.media/tomo/nasin/internal/icons/fallback"
-import "git.tebibyte.media/tomo/nasin/internal/style/fallback"
+import "git.tebibyte.media/tomo/nasin/internal/styles/fallback"
-// import "git.tebibyte.media/tomo/nasin/internal/style/aluminum"
+import "git.tebibyte.media/tomo/nasin/internal/faces/fallback"
 
-func RegisterBackend () error {
+type Registrar struct {
-	tomo.Register(1, x.New)
+	backend *x.Backend
-	return nil
+	iconSetCookie event.Cookie
+	styleCookie   event.Cookie
 }
 
-func SetTheme () error {
+func (this *Registrar) SetBackend () (tomo.Backend, error) {
-	var styl *tomo.Style
+	backend, err := x.New()
-	// TODO eventually get rid of this when we make a file format for
+	if err != nil { return nil, err }
-	// storing visual styles
+	this.backend = backend.(*x.Backend)
-	// TODO migrate aluminum
+	tomo.SetBackend(backend)
-	// if os.Getenv("TOMO_USE_ALUMINUM_STYLE") != "" {
+	return backend, nil
-		// styl = aluminumStyle.New()
+}
-	// } else {
+
-		styl = fallbackStyle.New()
+func (this *Registrar) SetStyle (name string) error {
-	// }
+	if this.styleCookie != nil {
-	icons := fallbackIcons.New()
+		this.styleCookie.Close()
-	
+		this.styleCookie = nil
-	iconThemeName := os.Getenv("TOMO_XDG_ICON_THEME")
+	}
-	if iconThemeName != "" {
+
-		xdgIconTheme, err := xdgIcons.FindThemeWarn(iconThemeName, icons)
+	if name != "" {
+		styl, cookie, err := tss.LoadFile(name)
 		if err == nil {
-			icons = xdgIconTheme
+			this.backend.SetStyle(styl)
+			this.styleCookie = cookie
+			return nil
 		} else {
-			log.Printf("nasin: could not load icon theme '%s': %v", iconThemeName, err)
+			log.Printf (
+				"nasin: could not load style sheet '%s'\n%v",
+				name, parse.Format(err))
 		}
 	}
 	
-	tomo.SetStyle(styl)
+	styl, cookie := fallbackStyle.New()
-	tomo.SetIconSet(icons)
+	this.styleCookie = cookie
-	return nil	
+	this.backend.SetStyle(styl)
+	return nil
+}
+
+func (this *Registrar) SetIconSet (name string) error {
+	if this.iconSetCookie != nil {
+		this.iconSetCookie.Close()
+		this.iconSetCookie = nil
+	}
+	
+	iconSet, cookie := fallbackIcons.New()
+	if name != "" {
+		xdgIconSet, xdgCookie, err := xdgIcons.FindThemeWarn(name, iconSet)
+		cookie = event.MultiCookie(cookie, xdgCookie)
+		if err == nil {
+			iconSet = xdgIconSet
+		} else {
+			log.Printf("nasin: could not load icon theme '%s': %v", name, err)
+		}
+	}
+	
+	this.backend.SetIconSet(iconSet)
+	this.iconSetCookie = cookie
+	return nil
+}
+
+func (this *Registrar) SetFaceSet () error {
+	// TODO replace this with something that uses findfont, and caches and
+	// refcounts the faces
+	faceSet := fallbackFaces.New()
+	this.backend.SetFaceSet(faceSet)
+	return nil
 }

internal/style/aluminum/aluminum.go

@@ -1,18 +0,0 @@
-package aluminumStyle
-
-import "image/color"
-import "git.tebibyte.media/tomo/tomo"
-
-// New returns Aluminum, a futuristic, bluish-white style.
-func New () *style.Style {
-	return &style.Style {
-		Colors: map[tomo.Color] color.Color {
-			tomo.ColorBackground: colorBackground,
-			tomo.ColorForeground: colorForeground,
-			tomo.ColorRaised:     colorRaised,
-			tomo.ColorSunken:     colorSunken,
-			tomo.ColorAccent:     colorFocus,
-		},
-		Rules: rules,
-	}
-}

internal/style/aluminum/style.go

@@ -1,391 +0,0 @@
-package aluminumStyle
-
-import "image/color"
-import "git.tebibyte.media/tomo/tomo"
-import "golang.org/x/image/font/basicfont"
-
-func hex (color uint32) (c color.RGBA) {
-	c.A = uint8(color)
-	c.B = uint8(color >>  8)
-	c.G = uint8(color >> 16)
-	c.R = uint8(color >> 24)
-	return
-}
-
-func border (top, right, bottom, left uint32, width ...int) tomo.Border {
-	return tomo.Border {
-		Width: tomo.I(width...),
-		Color: [4]color.Color {
-			hex(top),    hex(right),
-			hex(bottom), hex(left),
-		},
-	}
-}
-
-var colorDot                   = hex(0x7391c080)
-var colorFocus                 = hex(0x5f8bc4FF)
-var colorHighlight             = hex(0x5f8bc4FF)
-var colorBackground            = hex(0xd4d4d4FF)
-var colorForeground            = color.Black
-
-var colorOutline               = color.Black
-var colorGutter                = hex(0xbfc6d1FF)
-var colorGutterHovered         = hex(0xc5cbd6FF)
-var colorRaised                = hex(0xe9eaeaFF)
-var colorRaisedPressed         = hex(0xccd4ddFF)
-var colorRaisedFocused         = hex(0xcfd6ddFF)
-var colorRaisedHovered         = hex(0xf1f3f5FF)
-var colorSunken                = hex(0xe9eaeaFF)
-var colorSunkenFocused         = hex(0xe0e6eeFF)
-var colorSunkenPressed         = hex(0xe0e6eeFF)
-var colorCalendarWeekdayHeader = hex(0xd3cac2FF)
-var colorCalendarWeekend       = hex(0xc2d3c4FF)
-var colorCalendarDay           = hex(0xd6dae2FF)
-
-var outline = tomo.Border {
-	Width: tomo.I(1),
-	Color: [4]color.Color {
-		colorOutline,
-		colorOutline,
-		colorOutline,
-		colorOutline,
-	},
-}
-
-var borderEngraved       = border(0xc3c3c5FF, 0xe3e3e3FF, 0xe9e9e9ff, 0xc2c2c2ff, 1)
-var borderGap            = border(0x697c7cFF, 0x566767FF, 0x566767ff, 0x697c7cff, 1)
-var borderLifted         = border(0xf9fafcFF, 0xc2c8d3FF, 0xa4afc0ff, 0xf5f6f8ff, 1)
-var borderLiftedFocused  = border(0xf0f4f9FF, 0xb1bacaFF, 0x9aa6b7ff, 0xe4e9eeff, 1)
-var borderFocused        = border(0x5f8bc4FF, 0x5f8bc4FF, 0x5f8bc4ff, 0x5f8bc4ff, 1)
-var borderTear           = borderEngraved
-var borderTearFocused    = border(0x7f94b5FF, 0xced7e4FF, 0xced7e4FF, 0x7f94b5FF, 1)
-var borderTearPad        = border(0x00000000, 0x00000000, 0x00000000, 0x00000000, 3)
-var borderTearPadFocused = border(0x7391c080, 0x7391c080, 0x7391c080, 0x7391c080, 3)
-var borderInnerShadow    = border(0xa4afc0FF, 0xa4afc0FF, 0xa4afc0ff, 0xa4afc0ff, 1, 0, 0, 1)
-var borderOuterShadow    = border(0xa4afc0FF, 0xa4afc0FF, 0xa4afc0ff, 0xa4afc0ff, 0, 1, 1, 0)
-
-var rules = []style.Rule {
-	// *.*[*]
-	style.Rule {
-		Default: style.AS (
-			style.AttrFace      { Face:  basicfont.Face7x13    },
-			style.AttrTextColor { Color: tomo.ColorForeground  },
-			style.AttrDotColor  { Color: colorDot              },
-			style.AttrGap       { X: 8, Y: 8                   },
-		),
-	},
-
-	// *.Button[*]
-	style.Rule {
-		Role: tomo.R("", "Button", ""),
-		Default: style.AS (
-			style.AttrBorder {
-				borderEngraved,
-				borderGap,
-				borderLifted,
-			},
-			style.AttrPadding(tomo.I(4, 8)),
-			style.AttrColor { Color: tomo.ColorRaised },
-		),
-		Pressed: style.AS (
-			style.AttrBorder {
-				borderEngraved,
-				borderGap,
-				borderInnerShadow,
-			},
-			style.AttrPadding(tomo.I(5, 8, 4, 9)),
-			style.AttrColor { Color: colorRaisedPressed },
-		),
-		Focused: style.AS (
-			style.AttrBorder {
-				borderEngraved,
-				borderGap,
-				borderLiftedFocused,
-			},
-			style.AttrPadding(tomo.I(4, 8)),
-			style.AttrColor { Color: colorRaisedFocused },
-		),
-		Hovered: style.AS (
-			style.AttrColor { Color: colorRaisedHovered },
-		),
-	},
-
-	// *.TextInput[*]
-	style.Rule {
-		Role: tomo.R("", "TextInput", ""),
-		Default: style.AS (
-			style.AttrBorder {
-				borderEngraved,
-				borderGap,
-				borderInnerShadow,
-			},
-			style.AttrColor { Color: tomo.ColorSunken },
-			style.AttrPadding(tomo.I(5, 4, 4, 5)),
-		),
-		Focused: style.AS (
-			style.AttrBorder {
-				borderEngraved,
-				borderFocused,
-				borderInnerShadow,
-			},
-		),
-	},
-
-	// *.TextView[*]
-	style.Rule {
-		Role: tomo.R("", "TextView", ""),
-		Default: style.AS (
-			style.AttrBorder {
-				borderEngraved,
-				borderGap,
-				borderInnerShadow,
-			},
-			style.AttrColor { Color: tomo.ColorSunken },
-			style.AttrPadding(tomo.I(8)),
-		),
-	},
-	
-	// *.NumberInput[*]
-	style.Rule {
-		Role: tomo.R("", "NumberInput", ""),
-		Default: style.AS (
-			style.AttrGap { },
-		),
-	},
-
-	// *.Container[sunken]
-	style.Rule {
-		Role: tomo.R("", "Container", "sunken"),
-		Default: style.AS (
-			style.AttrBorder {
-				borderEngraved,
-				borderGap,
-				borderInnerShadow,
-			},
-			style.AttrColor { Color: tomo.ColorSunken },
-			style.AttrPadding(tomo.I(8)),
-		),
-	},
-
-	// *.Container[outer]
-	style.Rule {
-		Role: tomo.R("", "Container", "outer"),
-		Default: style.AS (
-			style.AttrColor { Color: tomo.ColorBackground },
-			style.AttrPadding(tomo.I(8)),
-		),
-	},
-
-	// *.Container[menu]
-	style.Rule {
-		Role: tomo.R("", "Container", "menu"),
-		Default: style.AS (
-			style.AttrBorder {
-				borderGap,
-				borderLifted,
-			},
-			style.AttrColor { Color: tomo.ColorBackground },
-			style.AttrGap { },
-		),
-	},
-
-	// *.Heading[*]
-	style.Rule {
-		Role: tomo.R("", "Heading", ""),
-		Default: style.AS (
-			style.AttrAlign { X: tomo.AlignMiddle, Y: tomo.AlignMiddle },
-		),
-	},
-
-	// *.Separator[*]
-	style.Rule {
-		Role: tomo.R("", "Separator", ""),
-		Default: style.AS (
-			style.AttrBorder {
-				borderEngraved,
-			},
-		),
-	},
-
-	// *.Slider[*]
-	style.Rule {
-		Role: tomo.R("", "Slider", ""),
-		Default: style.AS (
-			style.AttrBorder {
-				borderEngraved,
-				borderGap,
-				borderInnerShadow,
-			},
-			style.AttrColor { Color: colorGutter },
-		),
-		Focused: style.AS (
-			style.AttrBorder {
-				borderEngraved,
-				borderFocused,
-				borderInnerShadow,
-			},
-		),
-		Hovered: style.AS (
-			style.AttrColor { Color: colorGutterHovered },
-		),
-	},
-	
-	// *.Slider[horizontal]
-	style.Rule {
-		Role: tomo.R("", "Slider", "horizontal"),
-		Default: style.AS(style.AttrMinimumSize { X: 48 }),
-	},
-	
-	// *.Slider[vertical]
-	style.Rule {
-		Role: tomo.R("", "Slider", "vertical"),
-		Default: style.AS(style.AttrMinimumSize { Y: 48 }),
-	},
-
-	// *.SliderHandle[*]
-	style.Rule {
-		Role: tomo.R("", "SliderHandle", ""),
-		Default: style.AS (
-			style.AttrBorder {
-				borderOuterShadow,
-				borderGap,
-				borderLifted,
-			},
-			style.AttrColor { Color: tomo.ColorRaised },
-			style.AttrMinimumSize { X: 12, Y: 12, },
-		),
-	},
-
-	// *.Checkbox[*]
-	style.Rule {
-		Role: tomo.R("", "Checkbox", ""),
-		Default: style.AS (
-			style.AttrBorder {
-				borderEngraved,
-				borderGap,
-				borderInnerShadow,
-			},
-			style.AttrColor { Color: tomo.ColorSunken },
-			style.AttrPadding(tomo.I(0, 1, 1, 0)),
-			style.AttrMinimumSize { X: 19, Y: 19 },
-		),
-		Focused: style.AS (
-			style.AttrBorder {
-				borderEngraved,
-				borderFocused,
-				borderInnerShadow,
-			},
-			style.AttrPadding(tomo.I(0)),
-			style.AttrColor { Color: colorSunkenFocused },
-		),
-	},
-
-	// *.LabelCheckbox[*]
-	style.Rule {
-		Role: tomo.R("", "LabelCheckbox", ""),
-		Default: style.AS (
-			style.AttrGap { X: 8, Y: 8 },
-		),
-	},
-
-	// *.MenuItem[*]
-	style.Rule {
-		Role: tomo.R("", "MenuItem", ""),
-		Default: style.AS (
-			style.AttrPadding(tomo.I(4)),
-			style.AttrGap { X: 4, Y: 4 },
-			style.AttrColor { Color: color.Transparent },
-		),
-		Hovered: style.AS (
-			style.AttrColor { Color: colorDot },
-		),
-		Focused: style.AS (
-			style.AttrColor { Color: colorDot },
-		),
-	},
-
-	// *.File[*]
-	style.Rule {
-		Role: tomo.R("", "File", ""),
-		Default: style.AS (
-			style.AttrColor { Color: color.Transparent },
-		),
-		Focused: style.AS (
-			style.AttrColor { Color: colorDot },
-		),
-	},
-	
-	// *.TearLine[*]
-	style.Rule {
-		Role: tomo.R("", "TearLine", ""),
-		Default: style.AS (
-			style.AttrBorder {
-				borderTearPad,
-				borderTear,
-			},
-		),
-		Hovered: style.AS (
-			style.AttrBorder {
-				borderTearPadFocused,
-				borderTearFocused,
-			},
-		),
-		Focused: style.AS (
-			style.AttrBorder {
-				borderTearPadFocused,
-				borderTearFocused,
-			},
-		),
-	},
-	
-	// *.Calendar[*]
-	style.Rule {
-		Role: tomo.R("", "Calendar", ""),
-		Default: style.AS (
-			style.AttrBorder {
-				borderOuterShadow,
-				borderGap,
-			},
-			style.AttrColor { Color: tomo.ColorRaised },
-			style.AttrPadding(tomo.I(2)),
-			style.AttrGap { X: 2, Y: 2 },
-		),
-	},
-	
-	// *.CalendarGrid[*]
-	style.Rule {
-		Role: tomo.R("", "CalendarGrid", ""),
-		Default: style.AS (
-			style.AttrGap { X: 2, Y: 2 },
-		),
-	},
-	
-	// *.CalendarWeekdayHeader[*]
-	style.Rule {
-		Role: tomo.R("", "CalendarWeekdayHeader", ""),
-		Default: style.AS (
-			style.AttrPadding(tomo.I(2)),
-			style.AttrColor { Color: colorCalendarWeekdayHeader },
-		),
-	},
-	
-	// *.CalendarDay[weekday]
-	style.Rule {
-		Role: tomo.R("", "CalendarDay", "weekday"),
-		Default: style.AS (
-			style.AttrPadding(tomo.I(2)),
-			style.AttrMinimumSize { X: 32, Y: 32 },
-			style.AttrColor { Color: colorCalendarDay },
-		),
-	},
-
-	// *.CalendarDay[weekend]
-	style.Rule {
-		Role: tomo.R("", "CalendarDay", "weekend"),
-		Default: style.AS (
-			style.AttrPadding(tomo.I(2)),
-			style.AttrMinimumSize { X: 32, Y: 32 },
-			style.AttrColor { Color: colorCalendarWeekend },
-		),
-	},
-}

internal/style/fallback/wintergreen.go

@@ -1,19 +0,0 @@
-package fallbackStyle
-
-import "image/color"
-import "git.tebibyte.media/tomo/tomo"
-
-// New returns Wintergreen, the default Tomo style. It is neutral-gray with
-// green and turquoise accents.
-func New () *tomo.Style {
-	return &tomo.Style {
-		Rules: rules,
-		Colors: map[tomo.Color] color.Color {
-			tomo.ColorBackground: colorBackground,
-			tomo.ColorForeground: colorForeground,
-			tomo.ColorRaised:     colorCarved,
-			tomo.ColorSunken:     colorCarved,
-			tomo.ColorAccent:     colorFocus,
-		},
-	}
-}

internal/style/styleconcept.tss

@@ -1,21 +0,0 @@
-$colorBlack    = #000000FF
-$borderOutline = $black / 1
-
-*.Slider {
-	Border:  $borderOutline, $borderColorFocused / 1
-	Color:   $colorGutter
-	Padding: 0 1 1 0
-}
-
-*.Slider[focused] {
-	Border:  $borderOutline
-	Padding: 0
-}
-
-*.Slider[horizontal] {
-	MinimumSize: 48 0
-}
-
-*.Slider[vertical] {
-	MinimumSize: 0 48
-}

internal/styles/aluminum/aluminum.tss

@@ -0,0 +1,319 @@
+// Colors
+$ColorDot                   = #7391c080;
+$ColorAccent                = #5f8bc4;
+$ColorHighlight             = #5f8bc4;
+$ColorBackground            = #d4d4d4;
+$ColorForeground            = #000;
+$ColorOutline               = $ColorForeground;
+$ColorGutter                = #bfc6d1;
+$ColorGutterHovered         = #c5cbd6;
+$ColorRaised                = #e9eaea;
+$ColorRaisedPressed         = #ccd4dd;
+$ColorRaisedFocused         = #cfd6dd;
+$ColorRaisedHovered         = #f1f3f5;
+$ColorSunken                = #e9eaea;
+$ColorSunkenFocused         = #e0e6ee;
+$ColorSunkenPressed         = #e0e6ee;
+$ColorCalendarWeekdayHeader = #d3cac2;
+$ColorCalendarWeekend       = #c2d3c4;
+$ColorCalendarDay           = #d6dae2;
+
+// Borders
+$BorderOutline        = $ColorOutline                  ;
+$BorderEngraved       = #c3c3c5 #e3e3e3 #e9e9e9 #c2c2c2;
+$BorderGap            = #697c7c #566767 #566767 #697c7c;
+$BorderLifted         = #f9fafc #c2c8d3 #a4afc0 #f5f6f8;
+$BorderLiftedFocused  = #f0f4f9 #b1baca #9aa6b7 #e4e9ee;
+$BorderFocused        = #5f8bc4 #5f8bc4 #5f8bc4 #5f8bc4;
+$BorderTear           = $BorderEngraved                ;
+$BorderTearFocused    = #7f94b5 #ced7e4 #ced7e4 #7f94b5;
+$BorderTearPad        = #0000                          ;
+$BorderTearPadFocused = #7391c080                      ;
+$BorderInnerShadow    = #a4afc0                        ;
+$BorderOuterShadow    = #a4afc0                        ;
+
+*.* {
+	TextColor: $ColorForeground;
+	DotColor:  $ColorDot;
+	Gap:       8;
+}
+
+*.Button {
+	Border:  $BorderEngraved / 1, $BorderGap / 1, $BorderLifted / 1;
+	Padding: 4 8;
+	Color:   $ColorRaised;
+}
+
+*.Button[focused] {
+	Border:  $BorderEngraved / 1, $BorderGap / 1, $BorderLiftedFocused / 1;
+	Padding: 4 8;
+	Color:   $ColorRaisedFocused;
+}
+
+*.Button[hovered] {
+	Color: $ColorRaisedHovered;
+}
+
+*.Button[pressed] {
+	Border:  $BorderEngraved / 1, $BorderGap / 1, $BorderInnerShadow / 1 0 0 1;
+	Padding: 5 8 4 9;
+	Color:   $ColorRaisedPressed;
+}
+
+*.TextInput {
+	Border:  $BorderEngraved / 1, $BorderGap / 1, $BorderInnerShadow / 1 0 0 1;
+	Padding: 5 4 4 5;
+	Color:   $ColorSunken;
+}
+
+*.TextInput[focused] {
+	Border: $BorderEngraved / 1, $BorderFocused / 1, $BorderInnerShadow / 1 0 0 1;
+}
+
+*.TextView {
+	Border:  $BorderEngraved / 1, $BorderGap / 1, $BorderInnerShadow / 1 0 0 1;
+	Padding: 5 4 4 5;
+	Color:   $ColorSunken;
+}
+
+*.NumberInput {
+	Gap: 0;
+}
+
+*.Container[sunken] {
+	Border:  $BorderEngraved / 1, $BorderGap / 1, $BorderInnerShadow / 1 0 0 1;
+	Padding: 5 4 4 5;
+	Color:   $ColorSunken;
+}
+
+*.Container[outer] {
+	Color:   $ColorBackground;
+	Padding: 8;
+}
+
+*.Container[menu] {
+	Border: $BorderGap / 1, $BorderLifted / 1;
+	Color:  $ColorBackground;
+	Gap:    0;
+}
+
+*.Container[menu, torn] {
+	Border: ;
+	Color:  $ColorBackground;
+	Gap:    0;
+}
+
+*.Heading {
+	Align: middle middle;
+}
+
+*.Heading[menu] {
+	Align:   middle middle;
+	Padding: 4 8;
+}
+
+*.Separator {
+	Border: $BorderEngraved / 1;
+}
+
+*.Slider {
+	Border: $BorderEngraved / 1, $BorderGap / 1, $BorderInnerShadow / 1 0 0 1;
+	Color:  $ColorGutter;
+}
+
+*.Slider[focused] {
+	Border: $BorderEngraved / 1, $BorderFocused / 1, $BorderInnerShadow / 1 0 0 1;
+}
+
+*.Slider[hovered] {
+	Color: $ColorGutterHovered;
+}
+
+*.Slider[horizontal] {
+	MinimumSize: 48 0;
+}
+
+*.Slider[vertical] {
+	MinimumSize: 0 48;
+}
+
+*.SliderHandle {
+	Border:      $BorderOuterShadow / 0 1 1 0, $BorderGap / 1, $BorderLifted / 1;
+	Color:       $ColorRaised;
+	MinimumSize: 12;
+}
+
+*.Scrollbar {
+	Border: $BorderEngraved / 1, $BorderGap / 1, $BorderInnerShadow / 1 0 0 1;
+	Color:  $ColorGutter;
+}
+
+*.Scrollbar[focused] {
+	Border: $BorderEngraved / 1, $BorderFocused / 1, $BorderInnerShadow / 1 0 0 1;
+}
+
+*.Scrollbar[hovered] {
+	Color: $ColorGutterHovered;
+}
+
+*.Scrollbar[horizontal] {
+	MinimumSize: 48 0;
+}
+
+*.Scrollbar[vertical] {
+	MinimumSize: 0 48;
+}
+
+*.ScrollbarHandle {
+	Border:      $BorderOuterShadow / 0 1 1 0, $BorderGap / 1, $BorderLifted / 1;
+	Color:       $ColorRaised;
+	MinimumSize: 12;
+}
+
+*.ScrollContainer {
+	Gap: 0;
+}
+
+*.Checkbox {
+	Border:      $BorderEngraved / 1, $BorderGap / 1, $BorderInnerShadow / 1 0 0 1;
+	Color:       $ColorSunken;
+	Padding:     0 1 1 0;
+	MinimumSize: 19;
+}
+
+*.Checkbox[focused] {
+	Border:  $BorderEngraved / 1, $BorderFocused / 1, $BorderInnerShadow / 1 0 0 1;
+	Color:   $ColorSunkenFocused;
+	Padding: 0;
+}
+
+*.Checkbox[checked] {
+	Texture:     "assets/checkbox-checked.png";
+	TextureMode: center;
+}
+
+*.MenuItem {
+	Padding: 4;
+	Gap:     4;
+	Color:   #0000;
+}
+
+*.MenuItem[hovered] {
+	Color: $ColorDot;
+}
+
+*.MenuItem[focused] {
+	Color: $ColorDot;
+}
+
+*.File {
+	Color: #0000;
+}
+
+*.File[focused] {
+	Color: $ColorDot;
+}
+
+*.TearLine {
+	Border: $BorderTearPad / 3, $BorderTear / 1;
+}
+
+*.TearLine[hovered] {
+	Border: $BorderTearPadFocused / 3, $BorderTearFocused / 1;
+}
+
+*.TearLine[focused] {
+	Border: $BorderTearPadFocused / 3, $BorderTearFocused / 1;
+}
+
+*.Calendar {
+	Border:  $BorderOuterShadow / 0 1 1 0, $BorderGap / 1;
+	Color:   $ColorRaised;
+	Padding: 2;
+	Gap:     2;
+}
+
+*.CalendarGrid {
+	Gap: 2 2;
+}
+
+*.CalendarWeekdayHeader {
+	Color:   $ColorCalendarWeekdayHeader;
+	Padding: 2;
+}
+
+*.CalendarDay {
+	Color:       $ColorCalendarDay;
+	Padding:     2;
+	MinimumSize: 32;
+}
+
+*.CalendarDay[weekend] {
+	Color: $ColorCalendarWeekend;
+}
+
+*.TabbedContainer {
+	Gap: 0;
+}
+
+*.TabRow {
+	Border:  $BorderEngraved / 1 1 0 1, $BorderGap / 1 1 0 1, $BorderInnerShadow / 1 0 0 1;
+	Color:   $ColorSunken;
+	Gap:     0;
+	Padding: 1 0 0 0;
+}
+
+*.Tab {
+	Border:  #0000 / 1 0 0 0, $BorderOuterShadow / 0 1 0 0, $BorderGap / 1 1 0 1, $BorderLifted / 1;
+	Color:   $ColorSunken;
+	Padding: 4 8 2 8;
+}
+
+*.Tab[active] {
+	Border:  $BorderOuterShadow / 0 1 0 0, $BorderGap / 1 1 0 1, $BorderLifted / 1 1 0 1;
+	Color:   $ColorBackground;
+	Padding: 4 8;
+}
+
+*.TabSpacer {
+	Border: $BorderLifted / 0 0 1 0;
+	MinimumSize: 1 0;
+}
+
+*.Swatch {
+	Border:      $BorderEngraved / 1, $BorderGap / 1;
+	Color:       #FFF;
+	MinimumSize: 19;
+}
+
+*.Swatch[focused] {
+	Border: $BorderEngraved / 1, $BorderFocused / 1;
+}
+
+*.ColorPickerMap {
+	Border:      $BorderEngraved / 1, $BorderGap / 1;
+	Color:       $ColorSunken;
+	MinimumSize: 128;
+}
+
+*.Dropdown {
+	Border:  $BorderEngraved / 1, $BorderGap / 1, $BorderLifted / 1;
+	Padding: 4 8;
+	Color:   $ColorRaised;
+}
+
+*.Dropdown[focused] {
+	Border:  $BorderEngraved / 1, $BorderGap / 1, $BorderLiftedFocused / 1;
+	Padding: 4 8;
+	Color:   $ColorRaisedFocused;
+}
+
+*.Dropdown[hovered] {
+	Color: $ColorRaisedHovered;
+}
+
+*.Dropdown[pressed] {
+	Border:  $BorderEngraved / 1, $BorderGap / 1, $BorderInnerShadow / 1 0 0 1;
+	Padding: 5 8 4 9;
+	Color:   $ColorRaisedPressed;
+}

internal/styles/fallback/wintergreen.go

@@ -1,8 +1,14 @@
 package fallbackStyle
 
+import "io"
+import "bytes"
+import "image"
+import _ "embed"
+import _ "image/png"
 import "image/color"
 import "git.tebibyte.media/tomo/tomo"
-import "golang.org/x/image/font/basicfont"
+import "git.tebibyte.media/tomo/tomo/event"
+import "git.tebibyte.media/tomo/backend/style"
 
 var colorFocus                 = color.RGBA { R:  61, G: 128, B: 143, A: 255 }
 var colorInput                 = color.RGBA { R: 208, G: 203, B: 150, A: 255 }
@@ -38,17 +44,40 @@ var borderColorInput    = [4]color.Color { colorInputShadow, colorInput,     col
 var borderColorFocused  = [4]color.Color { colorFocus,       colorFocus,     colorFocus,     colorFocus       }
 var borderColorShade    = [4]color.Color { colorShade,       colorShade,     colorShade,     colorShade       }
 
-var rules = []tomo.Rule {
+//go:embed assets/atlas.png
+var atlasBytes []byte
+
+type closerCookie struct { io.Closer }
+func (cookie closerCookie) Close () { cookie.Closer.Close() }
+func newCloserCookie (closer io.Closer) event.Cookie {
+	return closerCookie { Closer: closer }
+}
+
+// New returns Wintergreen, the default Tomo style. It is neutral-gray with
+// green and turquoise accents.
+func New () (*style.Style, event.Cookie) {
+	atlasImage, _, err := image.Decode(bytes.NewReader(atlasBytes))
+	if err != nil { panic(err) }
+	atlasTexture := tomo.NewTexture(atlasImage)
+	
+	textureCheckboxChecked  := atlasTexture.SubTexture(image.Rect( 0,  0, 12, 11))
+	// textureCorkboard        := atlasTexture.SubTexture(image.Rect(16,  0, 28, 12))
+	textureTearLine         := atlasTexture.SubTexture(image.Rect(16, 12, 18, 13))
+	textureHandleVertical   := atlasTexture.SubTexture(image.Rect(28,  0, 29,  2))
+	textureHandleHorizontal := atlasTexture.SubTexture(image.Rect(28,  0, 30,  1))
+
+	cookie := event.MultiCookie(newCloserCookie(atlasTexture))
+
+rules := []style.Rule {
 	// *.*
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
-		tomo.AFace      (basicfont.Face7x13  ),
 		tomo.ATextColor (tomo.ColorForeground),
 		tomo.ADotColor  (tomo.ColorAccent    ),
 		tomo.AGap       (8, 8                ),
 	), tomo.R("", "")),
 
 	// *.Button
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			outline,
 			tomo.Border {
@@ -61,7 +90,7 @@ var rules = []tomo.Rule {
 	), tomo.R("", "Button")),
 
 	// *.Button[focused]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			outline,
 			tomo.Border {
@@ -69,11 +98,10 @@ var rules = []tomo.Rule {
 				Color: borderColorFocused,
 			},
 		},
-		tomo.AttrPadding(tomo.I(4, 8)),
 	), tomo.R("", "Button"), "focused"),
 	
 	// *.Button[pressed]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			outline,
 			tomo.Border {
@@ -86,7 +114,7 @@ var rules = []tomo.Rule {
 	), tomo.R("", "Button"), "pressed"),
 
 	// *.TextInput
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.ABorder (
 			outline,
 			tomo.Border {
@@ -98,7 +126,7 @@ var rules = []tomo.Rule {
 	), tomo.R("", "TextInput")),
 
 	// *.TextInput[focused]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.ABorder (
 			outline,
 			tomo.Border {
@@ -108,7 +136,7 @@ var rules = []tomo.Rule {
 	), tomo.R("", "TextInput"), "focused"),
 	
 	// *.TextView
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.ABorder (
 			outline,
 			tomo.Border {
@@ -120,31 +148,31 @@ var rules = []tomo.Rule {
 	), tomo.R("", "TextView")),
 	
 	// *.NumberInput
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AGap(0, 0),
 	), tomo.R("", "NumberInput")),
 
 	// *.Container[sunken]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
-		tomo.AttrBorder {
+		tomo.ABorder (
 			outline,
 			tomo.Border {
 				Width: tomo.I(1, 0, 0, 1),
 				Color: borderColorEngraved,
-			},
+			}),
-		},
+		tomo.AColor(tomo.ColorSunken),
-		tomo.AttrColor { Color: tomo.ColorSunken },
+		// tomo.ATexture(textureCorkboard),
-		tomo.AttrPadding(tomo.I(8)),
+		tomo.APadding(8),
 	), tomo.R("", "Container"), "sunken"),
 
 	// *.Container[outer]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrColor { Color: tomo.ColorBackground },
 		tomo.AttrPadding(tomo.I(8)),
 	), tomo.R("", "Container"), "outer"),
 
 	// *.Container[menu]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			outline,
 			tomo.Border {
@@ -157,12 +185,17 @@ var rules = []tomo.Rule {
 	), tomo.R("", "Container"), "menu"),
 
 	// *.Heading
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AAlign(tomo.AlignMiddle, tomo.AlignMiddle),
 	), tomo.R("", "Heading")),
+	
+	// *.Heading
+	style.Ru(style.AS (
+		tomo.APadding(4, 8),
+	), tomo.R("", "Heading"), "menu"),
 
 	// *.Separator
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			tomo.Border {
 				Width: tomo.I(1),
@@ -172,7 +205,7 @@ var rules = []tomo.Rule {
 	), tomo.R("", "Separator")),
 
 	// *.Slider
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			outline,
 			tomo.Border {
@@ -185,42 +218,117 @@ var rules = []tomo.Rule {
 	), tomo.R("", "Slider")),
 	
 	// *.Slider[focused]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
-			tomo.AttrBorder {
+		tomo.ABorder (
-				outline,
+			outline,
-				tomo.Border {
+			tomo.Border {
-					Width: tomo.I(1),
+				Width: tomo.I(1),
-					Color: borderColorFocused,
+				Color: borderColorFocused,
-				},
+			}),
-			},
+		tomo.APadding(0),
-			tomo.AttrPadding(tomo.I(0)),
 	), tomo.R("", "Slider"), "focused"),
 	
 	// *.Slider[horizontal]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AMinimumSize(48, 0),
 	), tomo.R("", "Slider"), "horizontal"),
 	
 	// *.Slider[vertical]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AMinimumSize(0, 48),
 	), tomo.R("", "Slider"), "vertical"),
 
 	// *.SliderHandle
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
-		tomo.AttrBorder {
+		tomo.ABorder (
 			outline,
 			tomo.Border {
 				Width: tomo.I(1),
 				Color: borderColorLifted,
 			},
-		},
+			tomo.Border {
-		tomo.AttrColor { Color: tomo.ColorRaised },
+				Width: tomo.I(1),
-		tomo.AttrMinimumSize { X: 12, Y: 12, },
+				Color: [4]color.Color {
+					tomo.ColorRaised, tomo.ColorRaised,
+					tomo.ColorRaised, tomo.ColorRaised,
+				},
+			}),
+		tomo.AColor(nil),
+		tomo.ATexture(textureHandleVertical),
+		tomo.AMinimumSize(12, 12),
 	), tomo.R("", "SliderHandle")),
 
+	// *.SliderHandle[horizontal]
+	style.Ru(style.AS (
+		tomo.ATexture(textureHandleHorizontal),
+	), tomo.R("", "SliderHandle"), "horizontal"),
+
+	// *.Scrollbar
+	style.Ru(style.AS (
+		tomo.AttrBorder {
+			outline,
+			tomo.Border {
+				Width: tomo.I(1, 0, 0, 1),
+				Color: borderColorEngraved,
+			},
+		},
+		tomo.AttrColor { Color: colorGutter },
+		tomo.AttrPadding(tomo.I(0, 1, 1, 0)),
+	), tomo.R("", "Scrollbar")),
+	
+	// *.Scrollbar[focused]
+	style.Ru(style.AS (
+		tomo.ABorder (
+			outline,
+			tomo.Border {
+				Width: tomo.I(1),
+				Color: borderColorFocused,
+			}),
+		tomo.APadding(0),
+	), tomo.R("", "Scrollbar"), "focused"),
+	
+	// *.Scrollbar[horizontal]
+	style.Ru(style.AS (
+		tomo.AMinimumSize(48, 0),
+	), tomo.R("", "Scrollbar"), "horizontal"),
+	
+	// *.Scrollbar[vertical]
+	style.Ru(style.AS (
+		tomo.AMinimumSize(0, 48),
+	), tomo.R("", "Scrollbar"), "vertical"),
+
+	// *.ScrollbarHandle
+	style.Ru(style.AS (
+		tomo.ABorder (
+			outline,
+			tomo.Border {
+				Width: tomo.I(1),
+				Color: borderColorLifted,
+			},
+			tomo.Border {
+				Width: tomo.I(1),
+				Color: [4]color.Color {
+					tomo.ColorRaised, tomo.ColorRaised,
+					tomo.ColorRaised, tomo.ColorRaised,
+				},
+			}),
+		tomo.AColor(nil),
+		tomo.ATexture(textureHandleVertical),
+		tomo.AMinimumSize(12, 12),
+	), tomo.R("", "ScrollbarHandle")),
+
+	// *.ScrollbarHandle[horizontal]
+	style.Ru(style.AS (
+		tomo.ATexture(textureHandleHorizontal),
+	), tomo.R("", "ScrollbarHandle"), "horizontal"),
+
+	// *.ScrollContainer
+	style.Ru(style.AS (
+		tomo.AGap(0, 0),
+	), tomo.R("", "ScrollContainer")),
+
 	// *.Checkbox
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.ABorder (
 			outline,
 			tomo.Border {
@@ -235,7 +343,7 @@ var rules = []tomo.Rule {
 	), tomo.R("", "Checkbox")),
 
 	// *.Checkbox[focused]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.ABorder (
 			outline,
 			tomo.Border {
@@ -246,40 +354,40 @@ var rules = []tomo.Rule {
 	), tomo.R("", "Checkbox"), "focused"),
 
 	// *.Checkbox[checked]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
-		tomo.ATexture(nil), // TODO: checked texture
+		tomo.ATexture(textureCheckboxChecked),
 	), tomo.R("", "Checkbox"), "checked"),
 
 	// *.MenuItem
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrPadding(tomo.I(4)),
 		tomo.AttrGap { X: 4, Y: 4 },
 		tomo.AttrColor { Color: color.Transparent },
 	), tomo.R("", "MenuItem")),
 
 	// *MenuItem[focused]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrColor { Color: tomo.ColorAccent },
 	), tomo.R("", "MenuItem"), "focused"),
 	
 	// *.MenuItem[hovered]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrColor { Color: tomo.ColorAccent },
 	), tomo.R("", "MenuItem"), "hovered"),
 
 	// *.File
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrColor { Color: color.Transparent },
 	), tomo.R("", "File")),
 
 	// *.File[focused]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrColor { Color: tomo.ColorAccent },
 	), tomo.R("", "File"), "focused"),
 
 	// *.TearLine
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
-		tomo.AttrBorder {
+		tomo.ABorder (
 			tomo.Border {
 				Width: tomo.I(3),
 				Color: [4]color.Color {
@@ -288,14 +396,13 @@ var rules = []tomo.Rule {
 					color.Transparent,
 					color.Transparent,
 				},
-			},
+			}),
-		},
+		tomo.ATexture(textureTearLine),
-		tomo.AttrColor { Color: tomo.ColorForeground },
+		tomo.APadding(1, 0, 0, 1),
-		tomo.AttrPadding(tomo.I(1, 0, 0, 1)),
 	), tomo.R("", "TearLine")),
 
 	// *.TearLine[focused]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			tomo.Border {
 				Width: tomo.I(3),
@@ -305,7 +412,7 @@ var rules = []tomo.Rule {
 	), tomo.R("", "TearLine"), "focused"),
 
 	// *.TearLine[hovered]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			tomo.Border {
 				Width: tomo.I(3),
@@ -315,7 +422,7 @@ var rules = []tomo.Rule {
 	), tomo.R("", "TearLine"), "hovered"),
 	
 	// *.Calendar
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			tomo.Border {
 				Width: tomo.I(0, 1, 1, 0),
@@ -329,37 +436,37 @@ var rules = []tomo.Rule {
 	), tomo.R("", "Calendar")),
 	
 	// *.CalendarGrid
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrGap { X: 2, Y: 2 },
 	), tomo.R("", "CalendarGrid")),
 	
 	// *.CalendarWeekdayHeader
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrPadding(tomo.I(2)),
 		tomo.AttrColor { Color: colorCalendarWeekdayHeader },
 	), tomo.R("", "CalendarWeekdayHeader")),
 	
 	// *.CalendarDay[weekday]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrPadding(tomo.I(2)),
 		tomo.AttrMinimumSize { X: 32, Y: 32 },
 		tomo.AttrColor { Color: colorCalendarDay },
 	), tomo.R("", "CalendarDay"), "weekday"),
 
 	// *.CalendarDay[weekend]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrPadding(tomo.I(2)),
 		tomo.AttrMinimumSize { X: 32, Y: 32 },
 		tomo.AttrColor { Color: colorCalendarWeekend },
 	), tomo.R("", "CalendarDay"), "weekend"),
 	
 	// *.TabbedContainer
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AGap(0, 0),
 	), tomo.R("", "TabbedContainer")),
 	
 	// *.TabRow
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			tomo.Border {
 				Width: tomo.I(1, 1, 0, 1),
@@ -376,7 +483,7 @@ var rules = []tomo.Rule {
 	), tomo.R("", "TabRow")),
 	
 	// *.TabSpacer[left]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			tomo.Border {
 				Width: tomo.I(0, 0, 1, 0),
@@ -391,7 +498,7 @@ var rules = []tomo.Rule {
 	), tomo.R("", "TabSpacer")),
 	
 	// *.TabSpacer[right]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			tomo.Border {
 				Width: tomo.I(1, 0, 0, 0),
@@ -417,7 +524,7 @@ var rules = []tomo.Rule {
 	), tomo.R("", "TabSpacer"), "right"),
 	
 	// *.Tab
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			tomo.Border {
 				Width: tomo.I(1, 0, 0, 0),
@@ -444,7 +551,7 @@ var rules = []tomo.Rule {
 	), tomo.R("", "Tab")),
 	
 	// *.Tab[active]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			tomo.Border {
 				Width: tomo.I(1, 0, 0, 1),
@@ -455,12 +562,12 @@ var rules = []tomo.Rule {
 				Color: borderColorLifted,
 			},
 		},
-		tomo.AttrPadding(tomo.I(4, 8, 4, 8)),
+		tomo.AttrPadding(tomo.I(4, 8, 7, 8)),
 		tomo.AttrColor { Color: tomo.ColorBackground },
 	), tomo.R("", "Tab"), "active"),
 
 	// *.Swatch
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			outline,
 		},
@@ -468,7 +575,7 @@ var rules = []tomo.Rule {
 	), tomo.R("", "Swatch")),
 
 	// *.Swatch[focused]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			outline,
 			tomo.Border {
@@ -479,7 +586,7 @@ var rules = []tomo.Rule {
 	), tomo.R("", "Swatch"), "focused"),
 
 	// *.ColorPickerMap
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			outline,
 			tomo.Border {
@@ -490,4 +597,53 @@ var rules = []tomo.Rule {
 		tomo.AttrColor { Color: tomo.ColorSunken },
 		tomo.AttrMinimumSize { X: 128, Y: 128 },
 	), tomo.R("", "ColorPickerMap")),
+	
+	// *.Dropdown
+	style.Ru(style.AS (
+		tomo.AttrBorder {
+			outline,
+			tomo.Border {
+				Width: tomo.I(1),
+				Color: borderColorLifted,
+			},
+		},
+		tomo.AttrPadding(tomo.I(4, 8)),
+		tomo.AttrColor { Color: tomo.ColorRaised },
+	), tomo.R("", "Dropdown")),
+
+	// *.Dropdown[focused]
+	style.Ru(style.AS (
+		tomo.AttrBorder {
+			outline,
+			tomo.Border {
+				Width: tomo.I(1),
+				Color: borderColorFocused,
+			},
+		},
+	), tomo.R("", "Dropdown"), "focused"),
+	
+	// *.Dropdown[pressed]
+	style.Ru(style.AS (
+		tomo.AttrBorder {
+			outline,
+			tomo.Border {
+				Width: tomo.I(1, 0, 0, 1),
+				Color: borderColorEngraved,
+			},
+		},
+		tomo.AttrPadding(tomo.I(5, 8, 4, 9)),
+		tomo.AttrColor { Color: colorCarvedPressed },
+	), tomo.R("", "Dropdown"), "pressed"),
+}
+
+	return &style.Style {
+		Rules: rules,
+		Colors: map[tomo.Color] color.Color {
+			tomo.ColorBackground: colorBackground,
+			tomo.ColorForeground: colorForeground,
+			tomo.ColorRaised:     colorCarved,
+			tomo.ColorSunken:     colorCarved,
+			tomo.ColorAccent:     colorFocus,
+		},
+	}, cookie
 }

internal/styles/misc/styleconcept.tss

@@ -0,0 +1,21 @@
+$colorBlack    = #000000FF;
+$borderOutline = $black 1;
+
+*.Slider {
+	Border:  $borderOutline, $borderColorFocused 1;
+	Color:   $colorGutter;
+	Padding: 0 1 1 0;
+}
+
+*.Slider[focused] {
+	Border:  $borderOutline;
+	Padding: 0;
+}
+
+*.Slider[horizontal] {
+	MinimumSize: 48 0;
+}
+
+*.Slider[vertical] {
+	MinimumSize: 0 48;
+}

internal/styles/misc/styleminimal.tss

@@ -0,0 +1,14 @@
+$ColorBackground = #FFF;
+$ColorForeground = #000;
+$ColorRaised     = #AAA;
+$ColorSunken     = #888;
+$ColorAccent     = #0FF;
+
+*.* {
+	Color:     $ColorBackground;
+	Border:    $ColorForeground / 1;
+	TextColor: $ColorForeground;
+	DotColor:  $ColorAccent;
+	Padding:   2;
+}
+

internal/styles/tss/build.go

@@ -0,0 +1,407 @@
+package tss
+
+import "os"
+import "io"
+import "fmt"
+import "image"
+import "errors"
+import "image/color"
+import _ "image/png"
+import "path/filepath"
+import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/event"
+import "git.tebibyte.media/tomo/tomo/canvas"
+import "git.tebibyte.media/tomo/backend/style"
+
+type styleBuilder struct {
+	sheet      Sheet
+	workingDir string
+	textures   map[string] canvas.TextureCloser
+}
+
+// BuildStyle builds a Tomo style from the specified sheet. Resources associated
+// with it (such as textures) can be freed by closing the returned cookie.
+func BuildStyle (sheet Sheet) (*style.Style, event.Cookie, error) {
+	builder := &styleBuilder {
+		sheet:      sheet,
+		workingDir: filepath.Dir(sheet.Path),
+	}
+	return builder.build()
+}
+
+func (this *styleBuilder) build () (*style.Style, event.Cookie, error) {
+	// ensure the sheet is flattened (all vars are resolved)
+	err := this.sheet.Flatten()
+	if err != nil { return nil, nil, err }
+	
+	getColor := func (name string) color.Color {
+		if list, ok := this.sheet.Variables[name]; ok {
+			if len(list) > 0 {
+				if col, ok := list[0].(ValueColor); ok {
+					return col				
+				}
+			}
+		}
+		return color.RGBA { R: 255, B: 255, A: 255 }
+	}
+
+	// construct style and get colors
+	cookies := []event.Cookie { }
+	sty := &style.Style {
+		Rules: make([]style.Rule, len(this.sheet.Rules)),
+		Colors: map[tomo.Color] color.Color {
+			tomo.ColorBackground: getColor("ColorBackground"),
+			tomo.ColorForeground: getColor("ColorForeground"),
+			tomo.ColorRaised:     getColor("ColorRaised"),
+			tomo.ColorSunken:     getColor("ColorSunken"),
+			tomo.ColorAccent:     getColor("ColorAccent"),
+		},
+	}
+
+	// build style rules from the sheet's rule slice
+	for index, rule := range this.sheet.Rules {
+		styleRule := style.Rule {
+			Role: tomo.Role {
+				Package: rule.Selector.Package,
+				Object:  rule.Selector.Object,
+			},
+			Tags: rule.Selector.Tags,
+			Set:  make(style.AttrSet),
+		}
+		for name, attr := range rule.Attrs {
+			styleAttr, cookie, err := this.buildAttr(name, attr)
+			if err != nil { return nil, nil, err }
+			styleRule.Set.Add(styleAttr)
+			if cookie != nil {
+				cookies = append(cookies, cookie)
+			}
+		}
+		sty.Rules[index] = styleRule
+	}
+
+	// add each texture to the cookies list
+	for _, texture := range this.textures {
+		cookies = append(cookies, closerCookie { Closer: texture })
+	}
+	
+	return sty, event.MultiCookie(cookies...), nil
+}
+
+func (this *styleBuilder) buildAttr (name string, attr []ValueList) (tomo.Attr, event.Cookie, error) {
+	errWrongType := func () error {
+		return errors.New(fmt.Sprintf("wrong type for %s attribute", name))
+	}
+	expectSingle := func () error {
+		if len(attr) != 1 {
+			return errors.New(fmt.Sprintf (
+				"%s attribute requires exactly one value list",
+				name))
+		}
+		return nil
+	}
+	expectSingleSingle := func () error {
+		err := expectSingle()
+		if err != nil { return err }
+		if len(attr[0]) != 1 {
+			return errors.New(fmt.Sprintf (
+				"%s attribute requires exactly one value",
+				name))
+		}
+		return nil
+	}
+	expectNumbers := func (list ValueList) error {
+		for _, value := range list {
+			if _, ok := value.(ValueNumber); ok { continue }
+			return errWrongType()
+		}
+		return nil
+	}
+	numbers := func (list ValueList) ([]int, error) {
+		nums := make([]int, len(list))
+		for index, value := range list {
+			if value, ok := value.(ValueNumber); ok {
+				nums[index] = int(value)
+				continue
+			}
+			return nil, errWrongType()
+		}
+		return nums, nil
+	}
+	bools := func (list ValueList) ([]bool, error) {
+		bools := make([]bool, len(list))
+		for index, value := range list {
+			if value, ok := value.(ValueKeyword); ok {
+				switch value {
+				case "true":
+					bools[index] = true
+					continue
+				case "false":
+					bools[index] = false
+					continue
+				}
+			}
+			return nil, errWrongType()
+		}
+		return bools, nil
+	}
+	point := func (list ValueList) (image.Point, error) {
+		err := expectNumbers(list)
+		if err != nil { return image.Point { }, err }
+		
+		vector := image.Point { }
+		switch len(attr[0]) {
+		case 1:
+			vector.X = int(list[0].(ValueNumber))
+			vector.Y = int(list[0].(ValueNumber))
+		case 2:
+			vector.X = int(list[0].(ValueNumber))
+			vector.Y = int(list[1].(ValueNumber))
+		default:
+			return image.Point { }, errors.New(fmt.Sprintf (
+				"%s attribute requires exactly one or two values",
+				name))
+		}
+		return vector, nil
+	}
+	
+	switch name {
+	case "Color":
+		err := expectSingleSingle()
+		if err != nil { return nil, nil, err }
+		if col, ok := attr[0][0].(ValueColor); ok {
+			return tomo.AColor(col), nil, nil
+		}
+		return nil, nil, errWrongType()
+		
+	case "Texture":
+		err := expectSingleSingle()
+		if err != nil { return nil, nil, err }
+		if name, ok := attr[0][0].(ValueString); ok {
+			texture, err := this.texture(string(name))
+			if err != nil { return nil, nil, err }
+			return tomo.ATexture(texture), nil, nil
+		}
+		return nil, nil, errWrongType()
+	
+	case "TextureMode":
+		err := expectSingleSingle()
+		if err != nil { return nil, nil, err }
+		if keyword, ok := attr[0][0].(ValueKeyword); ok {
+			switch keyword {
+			case "tile":   return tomo.ATextureMode(tomo.TextureModeCenter), nil, nil
+			case "center": return tomo.ATextureMode(tomo.TextureModeCenter), nil, nil
+			}
+			return nil, nil, errors.New(fmt.Sprintf (
+				"unknown texture mode: %s",
+				keyword))
+		}
+		return nil, nil, errWrongType()
+	
+	case "Border":
+		attrBorder, err := buildAttrBorder(attr)
+		if err != nil { return nil, nil, err }
+		return attrBorder, nil, nil
+	
+	case "MinimumSize":
+		err := expectSingle()
+		if err != nil { return nil, nil, err }
+		vector, err := point(attr[0])
+		if err != nil { return nil, nil, err }
+		return tomo.AttrMinimumSize(vector), nil, nil
+	
+	case "Padding":
+		err := expectSingle()
+		if err != nil { return nil, nil, err }
+		numbers, err := numbers(attr[0])
+		if err != nil { return nil, nil, err }
+		inset := tomo.Inset { }
+		if !copyBorderValue(inset[:], numbers) {
+			return nil, nil, errors.New(fmt.Sprintf (
+				"%s attribute requires exactly one, two, or four values",
+				name))
+		}
+		return tomo.AttrPadding(inset), nil, nil
+		
+	case "Gap":
+		err := expectSingle()
+		if err != nil { return nil, nil, err }
+		vector, err := point(attr[0])
+		if err != nil { return nil, nil, err }
+		return tomo.AttrGap(vector), nil, nil
+	
+	case "TextColor":
+		err := expectSingleSingle()
+		if err != nil { return nil, nil, err }
+		if col, ok := attr[0][0].(ValueColor); ok {
+			return tomo.ATextColor(col), nil, nil
+		}
+		return nil, nil, errWrongType()
+			
+	case "DotColor":
+		err := expectSingleSingle()
+		if err != nil { return nil, nil, err }
+		if col, ok := attr[0][0].(ValueColor); ok {
+			return tomo.ADotColor(col), nil, nil
+		}
+		return nil, nil, errWrongType()
+			
+	case "Face":
+		// TODO support weight, italic, slant
+		err := expectSingle()
+		if err != nil { return nil, nil, err }
+		list := attr[0]
+		if len(list) != 2 {
+			return nil, nil, errors.New(fmt.Sprintf (
+				"%s attribute requires exactly two values",
+				name))
+		}
+		name, ok := list[0].(ValueString)
+		if !ok { return nil, nil, errWrongType() }
+		size, ok := list[1].(ValueNumber)
+		if !ok { return nil, nil, errWrongType() }
+		return tomo.AFace(tomo.Face {
+			Font: string(name),
+			Size: float64(size),
+		}), nil, nil
+		
+	case "Wrap":
+		err := expectSingleSingle()
+		if err != nil { return nil, nil, err }
+		if value, ok := attr[0][0].(ValueKeyword); ok {
+			switch value {
+			case "true":  return tomo.AWrap(true),  nil, nil
+			case "false": return tomo.AWrap(false), nil, nil
+			}
+		}
+		return nil, nil, errWrongType()
+		
+	case "Align":
+		err := expectSingle()
+		if err != nil { return nil, nil, err }
+		list := attr[0]
+		if len(list) != 2 {
+			return nil, nil, errors.New(fmt.Sprintf (
+				"%s attribute requires exactly two values",
+				name))
+		}
+		aligns := [2]tomo.Align { }
+		for index, value := range list {
+			if keyword, ok := value.(ValueKeyword); ok {
+				switch keyword {
+				case "start":  aligns[index] = tomo.AlignStart;  continue
+				case "middle": aligns[index] = tomo.AlignMiddle; continue
+				case "end":    aligns[index] = tomo.AlignEnd;    continue
+				case "even":   aligns[index] = tomo.AlignEven;   continue
+				default: return nil, nil, errors.New(fmt.Sprintf (
+					"unknown texture mode: %s",
+					keyword))					
+				}
+			}
+			return nil, nil, errWrongType()
+		}
+		return tomo.AAlign(aligns[0], aligns[1]), nil, nil
+		
+	case "Overflow":
+		err := expectSingle()
+		if err != nil { return nil, nil, err }
+		bools, err := bools(attr[0])
+		if err != nil { return nil, nil, err }
+		if len(bools) != 2 {
+			return nil, nil, errors.New(fmt.Sprintf (
+				"%s attribute requires exactly two values",
+				name))
+		}
+		return tomo.AOverflow(bools[0], bools[1]), nil, nil
+		
+	case "Layout":
+		// TODO allow use of some layouts in the objects package
+		
+	default: return nil, nil, errors.New(fmt.Sprintf("unknown attribute name %s", name))
+	}
+	return nil, nil, errors.New(fmt.Sprintf("unimplemented attribute name %s", name))
+}
+
+func (this *styleBuilder) texture (path string) (canvas.TextureCloser, error) {
+	path = filepath.Join(this.workingDir, path)
+	if texture, ok := this.textures[path]; ok {
+		return texture, nil
+	}
+	file, err := os.Open(path)
+	if err != nil { return nil, err }
+	defer file.Close()
+	rawImage, _, err := image.Decode(file)
+	if err != nil { return nil, err }
+	return tomo.NewTexture(rawImage), nil
+}
+
+func buildAttrBorder (attr []ValueList) (tomo.Attr, error) {
+	borders := make([]tomo.Border, len(attr))
+	for index, list := range attr {
+		colors := make([]color.Color, 0, len(list))
+		sizes  := make([]int, 0, len(list))
+		
+		capturingSize := false
+		for _, value := range list {
+			if capturingSize {
+				if value, ok := value.(ValueNumber); ok {
+					sizes = append(sizes, int(value))
+					continue
+				}
+			} else {
+				if _, ok := value.(ValueCut); ok {
+					capturingSize = true
+					continue
+				}
+				if value, ok := value.(ValueColor); ok {
+					colors = append(colors, value)
+					continue
+				}
+			}
+			return nil, errors.New("malformed Border attribute value list")
+		}
+		
+		border := tomo.Border { }
+		if !copyBorderValue(border.Width[:], sizes) {
+			return nil, errors.New("malformed Border attribute width list")
+		}
+		if !copyBorderValue(border.Color[:], colors) {
+			return nil, errors.New("malformed Border attribute color list")
+		}
+		borders[index] = border
+	}
+	
+	return tomo.ABorder(borders...), nil
+}
+
+func copyBorderValue[T any, U ~[]T] (destination, source U) bool {
+	if len(source) > len(destination) { return false } 
+	switch len(source) {
+	case 1:
+		destination[0] = source[0]
+		destination[1] = source[0]
+		destination[2] = source[0]
+		destination[3] = source[0]
+		return true
+	case 2:
+		destination[0] = source[0]
+		destination[1] = source[1]
+		destination[2] = source[0]
+		destination[3] = source[1]
+		return true
+	case 4:
+		destination[0] = source[0]
+		destination[1] = source[1]
+		destination[2] = source[2]
+		destination[3] = source[3]
+		return true
+	default:
+		return false
+	}
+}
+
+type closerCookie struct {
+	io.Closer
+}
+func (cookie closerCookie) Close () {
+	cookie.Closer.Close()
+}

internal/styles/tss/color_test.go

@@ -0,0 +1,17 @@
+package tss
+
+import "testing"
+
+func TestValueColor (test *testing.T) {
+	testValueColorRGBA(test, 0xFB380CFF, 0xFBFB, 0x3838, 0x0C0C, 0xFFFF)
+	testValueColorRGBA(test, 0xFB380C00, 0x0000, 0x0000, 0x0000, 0x0000)
+}
+
+func testValueColorRGBA (test *testing.T, col ValueColor, r, g, b, a uint32) {
+	gr, gg, gb, ga := col.RGBA()
+	test.Logf("testing RGBA for color #%08X", col)
+	if gr != r { test.Errorf("r component inequal (%04X != %04X)", gr, r) }
+	if gg != g { test.Errorf("g component inequal (%04X != %04X)", gg, g) }
+	if gb != b { test.Errorf("b component inequal (%04X != %04X)", gb, b) }
+	if ga != a { test.Errorf("a component inequal (%04X != %04X)", ga, a) }
+}

internal/styles/tss/flatten.go

@@ -0,0 +1,53 @@
+package tss
+
+import "fmt"
+import "errors"
+
+// Flatten evaluates all variables recursively, thereby eliminating all
+// instances of ValueVariable.
+func (this *Sheet) Flatten () error {
+	if this.flat { return nil }
+	this.flat = true
+	
+	for name, variable := range this.Variables {
+		variable, err := this.eval(variable)
+		if err != nil { return err }
+		this.Variables[name] = variable
+	}
+	
+	for index, rule := range this.Rules {
+		for name, attr := range rule.Attrs {
+			for index, list := range attr {
+				list, err := this.eval(list)
+				if err != nil { return err }
+				attr[index] = list
+			}
+			rule.Attrs[name] = attr
+		}
+		this.Rules[index] = rule
+	}
+	
+	return nil
+}
+
+func (this *Sheet) eval (source ValueList) (ValueList, error) {
+	destination := make(ValueList, 0, len(source))
+	for _, value := range source {
+		if name, ok := value.(ValueVariable); ok {
+			variable, ok := this.Variables[string(name)]
+			if !ok {
+				return nil, errors.New(fmt.Sprintf(
+					"variable $%s does not exist",
+					value))
+			}
+			variable, err := this.eval(variable)
+			if err != nil { return nil, err }
+			destination = append(destination, variable...)
+			continue
+		} else {
+			destination = append(destination, value)
+		}
+	}
+	
+	return destination, nil
+}

internal/styles/tss/lex.go

@@ -0,0 +1,363 @@
+package tss
+
+import "io"
+import "bufio"
+import "unicode"
+import "unicode/utf8"
+import "git.tebibyte.media/sashakoshka/goparse"
+
+const (
+	Comment parse.TokenKind = iota
+	LBrace
+	RBrace
+	LBracket
+	RBracket
+	Equals
+	Colon
+	Comma
+	Semicolon
+	Star
+	Dot
+	Dollar
+	Slash
+	Color
+	Ident
+	Number
+	String
+)
+
+var tokenNames = map[parse.TokenKind] string {
+	parse.EOF: "EOF",
+	Comment: "Comment",
+	LBrace: "LBrace",
+	RBrace: "RBrace",
+	LBracket: "LBracket",
+	RBracket: "RBracket",
+	Equals: "Equals",
+	Colon: "Colon",
+	Comma: "Comma",
+	Semicolon: "Semicolon",
+	Star: "Star",
+	Dot: "Dot",
+	Dollar: "Dollar",
+	Slash: "Slash",
+	Color: "Color",
+	Ident: "Ident",
+	Number: "Number",
+	String: "String",
+}
+
+type lexer struct {
+	filename    string
+	lineScanner *bufio.Scanner
+	rune        rune
+	line        string
+	lineFood    string
+
+	offset   int
+	row      int
+	column   int
+
+	eof bool
+}
+
+func Lex (filename string, reader io.Reader) parse.Lexer {
+	lex := &lexer {
+		filename:    filename,
+		lineScanner: bufio.NewScanner(reader),
+	}
+	lex.nextRune()
+	return lex
+}
+
+func (this *lexer) Next () (parse.Token, error) {
+	for {
+		token, err := this.next()
+		if err == io.EOF { return token, this.errUnexpectedEOF() }
+		if err != nil    { return token, err                     }
+
+		if !token.Is(Comment) {
+			return token, err
+		}
+	}
+}
+
+func (this *lexer) next () (token parse.Token, err error) {
+	err = this.skipWhitespace()
+	token.Position = this.pos()
+	if this.eof {
+		token.Kind = parse.EOF
+		err = nil
+		return
+	}
+	if err != nil { return }
+
+	appendRune := func () {
+		token.Value += string(this.rune)
+		err = this.nextRune()
+	}
+
+	skipRune := func () {
+		err = this.nextRune()
+	}
+
+	defer func () {
+		newPos := this.pos()
+		newPos.End --
+		token.Position = token.Position.Union(newPos)
+	} ()
+
+	switch {
+	case this.rune == '/':
+		token.Kind = Comment
+		skipRune()
+		if err != nil { return }
+		if this.rune == '/' {
+			for this.rune != '\n' {
+				skipRune()
+				if err != nil { return }
+			}
+		} else {
+			token.Kind = Slash
+		}
+		if this.eof { err = nil; return }
+
+	case this.rune == '{':
+		token.Kind = LBrace
+		appendRune()
+		if this.eof { err = nil; return }
+
+	case this.rune == '}':
+		token.Kind = RBrace
+		appendRune()
+		if this.eof { err = nil; return }
+
+	case this.rune == '[':
+		token.Kind = LBracket
+		appendRune()
+		if this.eof { err = nil; return }
+
+	case this.rune == ']':
+		token.Kind = RBracket
+		appendRune()
+		if this.eof { err = nil; return }
+
+	case this.rune == '=':
+		token.Kind = Equals
+		appendRune()
+		if this.eof { err = nil; return }
+
+	case this.rune == ':':
+		token.Kind = Colon
+		appendRune()
+		if this.eof { err = nil; return }
+
+	case this.rune == ',':
+		token.Kind = Comma
+		appendRune()
+		if this.eof { err = nil; return }
+
+	case this.rune == ';':
+		token.Kind = Semicolon
+		appendRune()
+		if this.eof { err = nil; return }
+
+	case this.rune == '*':
+		token.Kind = Star
+		appendRune()
+		if this.eof { err = nil; return }
+
+	case this.rune == '.':
+		token.Kind = Dot
+		appendRune()
+		if this.eof { err = nil; return }
+
+	case this.rune == '$':
+		token.Kind = Dollar
+		appendRune()
+		if this.eof { err = nil; return }
+
+	case this.rune == '#':
+		token.Kind = Color
+		skipRune()
+		if err != nil { return }
+		for isHexDigit(this.rune) {
+			appendRune()
+			if this.eof { err = nil; return }
+		}
+		if this.eof { err = nil; return }
+
+	case unicode.IsLetter(this.rune):
+		token.Kind = Ident
+		for unicode.IsLetter(this.rune) || unicode.IsNumber(this.rune) {
+			appendRune()
+			if this.eof { err = nil; return }
+		}
+		if this.eof { err = nil; return }
+
+	case this.rune == '-':
+		token.Kind = Number
+		appendRune()
+		for isDigit(this.rune) {
+			appendRune()
+			if this.eof { err = nil; return }
+		}
+		if this.eof { err = nil; return }
+		
+	case isDigit(this.rune):
+		token.Kind = Number
+		for isDigit(this.rune) {
+			appendRune()
+			if this.eof { err = nil; return }
+		}
+		if this.eof { err = nil; return }
+		
+	case this.rune == '\'', this.rune == '"':
+		stringDelimiter := this.rune
+		token.Kind = String
+		err = this.nextRune()
+		if err != nil { return }
+
+		for this.rune != stringDelimiter {
+			if this.rune == '\\' {
+				var result rune
+				result, err = this.escapeSequence(stringDelimiter)
+				if err != nil { return }
+				token.Value += string(result)
+			} else {
+				appendRune()
+				if this.eof { err = nil; return }
+				if err != nil { return }
+			}
+		}
+		err = this.nextRune()
+		if this.eof { err = nil; return }
+		if err != nil { return }
+
+	default:
+		err = parse.Errorf (
+			this.pos(), "unexpected rune %U",
+			this.rune)
+	}
+
+	return
+}
+
+func (this *lexer) nextRune () error {
+	if this.lineFood == "" {
+		ok := this.lineScanner.Scan()
+		if ok {
+			this.line     = this.lineScanner.Text()
+			this.lineFood = this.line
+			this.rune     = '\n'
+			this.column   = 0
+			this.row      ++
+		} else {
+			err := this.lineScanner.Err()
+			if err == nil {
+				this.eof = true
+				return io.EOF
+			} else {
+				return err
+			}
+		}
+	} else {
+		var ch   rune
+		var size int
+		for ch == 0 && this.lineFood != "" {
+			ch, size = utf8.DecodeRuneInString(this.lineFood)
+			this.lineFood = this.lineFood[size:]
+		}
+		this.rune = ch
+		this.column ++
+	}
+
+	return nil
+}
+
+func (this *lexer) escapeSequence (stringDelimiter rune) (rune, error) {
+	err := this.nextRune()
+	if err != nil { return 0, err }
+
+	if isDigit(this.rune) {
+		var number rune
+		for index := 0; index < 3; index ++ {
+			if !isDigit(this.rune) { break }
+		
+			number *= 8
+			number += this.rune - '0'
+
+			err = this.nextRune()
+			if err != nil { return 0, err }
+		}
+		return number, nil
+	}
+
+	defer this.nextRune()
+	switch this.rune {
+	case '\\', '\n', stringDelimiter:
+		return this.rune, nil
+	case 'a': return '\a', nil
+	case 'b': return '\b', nil
+	case 't': return '\t', nil
+	case 'n': return '\n', nil
+	case 'v': return '\v', nil
+	case 'f': return '\f', nil
+	case 'r': return '\r', nil
+	default: return 0, this.errBadEscapeSequence()
+	}
+}
+
+func (this *lexer) skipWhitespace () error {
+	for isWhitespace(this.rune) {
+		err := this.nextRune()
+		if err != nil { return err }
+	}
+	return nil
+}
+
+func (this *lexer) pos () parse.Position {
+	return parse.Position {
+		File:   this.filename,
+		Line:   this.lineScanner.Text(),
+		Row:    this.row    - 1,
+		Start:  this.column - 1,
+		End:    this.column,
+	}
+}
+
+func (this *lexer) errUnexpectedEOF () error {
+	return parse.Errorf(this.pos(), "unexpected EOF")
+}
+
+func (this *lexer) errBadEscapeSequence () error {
+	return parse.Errorf(this.pos(), "bad escape sequence")
+}
+
+func isWhitespace (char rune) bool {
+	switch char {
+	case ' ', '\t', '\r', '\n': return true
+	default: return false
+	}
+}
+
+func isSymbol (char rune) bool {
+	switch char {
+	case
+		'~', '!', '@', '#', '$', '%', '^', '&', '-', '_', '=', '+',
+		'\\', '|', ';', ',', '<', '>', '/', '?':
+		return true
+	default:
+		return false
+	}
+}
+
+func isDigit (char rune) bool {
+	return char >= '0' && char <= '9'
+}
+
+func isHexDigit (char rune) bool {
+	return isDigit(char) ||
+		char >= 'a' && char <= 'f' ||
+		char >= 'A' && char <= 'F'
+}

internal/styles/tss/lex_test.go

@@ -0,0 +1,66 @@
+package tss
+
+import "fmt"
+import "strings"
+import "testing"
+import "git.tebibyte.media/sashakoshka/goparse"
+
+func TestLexSimple (test *testing.T) {
+testString(test,
+`hello #BABE {#Beef}, 384920 #0ab3fc840`,
+tok(Ident, "hello"),
+tok(Color, "BABE"),
+tok(LBrace, "{"),
+tok(Color, "Beef"),
+tok(RBrace, "}"),
+tok(Comma, ","),
+tok(Number, "384920"),
+tok(Color, "0ab3fc840"),
+tok(parse.EOF, ""),
+)}
+
+func testString (test *testing.T, input string, correct ...parse.Token) {
+	lexer := Lex("test.tss", strings.NewReader(input))
+	index := 0
+	for {
+		token, err := lexer.Next()
+		if err != nil { test.Fatalf("lexer returned error:\n%v", parse.Format(err)) }
+		if index >= len(correct) {
+			test.Logf("%d:\t%-16s | !", index, tokStr(token))
+			test.Fatalf("index %d greater than %d", index, len(correct))
+		}
+		correctToken := correct[index]
+		test.Logf (
+			"%d:\t%-16s | %s",
+			index,
+			tokStr(token),
+			tokStr(correctToken))
+		if correctToken.Kind != token.Kind || correctToken.Value != token.Value {
+			test.Fatalf("tokens at %d do not match up", index)
+		}
+		if token.Is(parse.EOF) { break }
+		index ++
+	}
+	if index < len(correct) - 1 {
+		test.Fatalf("index %d less than %d", index, len(correct) - 1)
+	}
+}
+
+func tokStr (token parse.Token) string {
+	name, ok := tokenNames[token.Kind]
+	if !ok {
+		name = fmt.Sprintf("Token(%d)", token.Kind)
+	}
+	if token.Value == "" {
+		return name
+	} else {
+		return fmt.Sprintf("%s:\"%s\"", name, token.Value)
+	}
+}
+
+func tok (kind parse.TokenKind, value string) parse.Token {
+	return parse.Token {
+		Kind:  kind,
+		Value: value,
+	}
+}

internal/styles/tss/parse.go

@@ -0,0 +1,254 @@
+package tss
+
+import "io"
+import "strconv"
+import "git.tebibyte.media/sashakoshka/goparse"
+
+type parser struct {
+	parse.Parser
+	sheet Sheet
+	lexer parse.Lexer
+}
+
+func newParser (lexer parse.Lexer) *parser {
+	return &parser {
+		sheet: Sheet {
+			Variables: make(map[string] ValueList),
+		},
+		Parser: parse.Parser {
+			Lexer:      lexer,
+			TokenNames: tokenNames,
+		},
+	}
+}
+
+func Parse (lexer parse.Lexer) (Sheet, error) {
+	parser := newParser(lexer)
+	err := parser.parse()
+	if err == io.EOF { err = nil }
+	if err != nil { return Sheet { }, err }
+	return parser.sheet, nil
+}
+
+func (this *parser) parse () error {
+	err := this.Next()
+	if err != nil { return err }
+	for this.Token.Kind != parse.EOF {
+		err = this.parseTopLevel()
+		if err != nil { return err }
+	}
+	return nil
+}
+
+func (this *parser) parseTopLevel () error {
+	err := this.ExpectDesc("variable or rule", Dollar, Ident, Star)
+	if err != nil { return err }
+	if this.EOF() { return nil }
+	pos := this.Pos()
+	
+	switch this.Kind() {
+	case Dollar:
+		name, variable, err := this.parseVariable()
+		if err != nil { return err }
+		if _, exists := this.sheet.Variables[name]; exists {
+			return parse.Errorf(pos, "variable %s already declared", name)
+		}
+		this.sheet.Variables[name] = variable
+		
+	case Ident, Star:
+		rule, err := this.parseRule()
+		if err != nil { return err }
+		this.sheet.Rules = append(this.sheet.Rules, rule)
+	}
+	return nil
+}
+
+func (this *parser) parseVariable () (string, ValueList, error) {
+	err := this.Expect(Dollar)
+	if err != nil { return "", nil, err }
+	err = this.ExpectNext(Ident)
+	if err != nil { return "", nil, err }
+	name := this.Value()
+	err = this.ExpectNext(Equals)
+	if err != nil { return "", nil, err }
+	this.Next()
+	values, err := this.parseValueList()
+	if err != nil { return "", nil, err }
+	err = this.Expect(Semicolon)
+	if err != nil { return "", nil, err }
+	return name, values, this.Next()
+}
+
+func (this *parser) parseRule () (Rule, error) {
+	rule := Rule {
+		Attrs: make(map[string] []ValueList),
+	}
+	
+	selector, err := this.parseSelector()
+	if err != nil { return Rule { }, err }
+	rule.Selector = selector
+	err = this.Expect(LBrace)
+	if err != nil { return Rule { }, err }
+	
+	for {
+		this.Next()
+		if this.Is(RBrace) { break }
+		pos := this.Pos()
+		name, attr, err := this.parseAttr()
+		if err != nil { return Rule { }, err }
+		err = this.Expect(Semicolon)
+		if err != nil { return Rule { }, err }
+		if _, exists := rule.Attrs[name]; exists {
+			return Rule { }, parse.Errorf (
+				pos,
+				"attribute %s already declared in this rule",
+				name)
+		}
+		rule.Attrs[name] = attr
+	}
+	
+	return rule, this.Next()
+}
+
+func (this *parser) parseSelector () (Selector, error) {
+	selector := Selector { }
+
+	// package
+	err := this.ExpectDesc("selector", Ident, Star)
+	if err != nil { return Selector { }, err }
+	if this.Is(Ident) {
+		selector.Package = this.Value()
+	}
+	
+	err = this.ExpectNext(Dot)
+	if err != nil { return Selector { }, err }
+
+	// object
+	err = this.ExpectNext(Ident, Star)
+	if err != nil { return Selector { }, err }
+	if this.Is(Ident) {
+		selector.Object = this.Value()
+	}
+
+	// tags
+	err = this.ExpectNext(LBracket)
+	if err == nil {
+		for {
+			this.Next()
+			err := this.Expect(Ident, String, RBracket)
+			if err != nil { return Selector { }, err }
+			if this.Is(RBracket) { break       }
+			if this.Is(Comma)    { this.Next() }
+			selector.Tags = append(selector.Tags, this.Value())
+			err = this.ExpectNext(Comma, RBracket)
+			if err != nil { return Selector { }, err }
+			if this.Is(RBracket) { break }
+		}
+		this.Next()
+	}
+	
+	return selector, nil
+}
+
+func (this *parser) parseAttr () (string, []ValueList, error) {
+	err := this.ExpectDesc("attr", Ident)
+	if err != nil { return "", nil, err }
+	name := this.Value()
+
+	err = this.ExpectNext(Colon)
+	if err != nil { return "", nil, err }
+
+	attr := []ValueList { }
+	this.Next()
+	for {
+		err := this.ExpectDesc (
+			"value, Comma, or Semicolon",
+			Number, Color, String, Ident, Dollar, Slash,
+			Comma, Semicolon)
+		if err != nil { return "", nil, err }
+		if this.Is(Semicolon) { break       }
+		if this.Is(Comma)     { this.Next() }
+		valueList, err := this.parseValueList()
+		if err != nil { return "", nil, err }
+		attr = append(attr, valueList)
+		err = this.Expect(Comma, Semicolon)
+		if err != nil { return "", nil, err }
+	}
+	
+	return name, attr, nil
+}
+
+func (this *parser) parseValueList () (ValueList, error) {
+	list := ValueList { }
+	for {
+		err := this.ExpectDesc (
+			"value",
+			Number, Color, String, Ident, Dollar, Slash)
+		if err != nil { break }
+		switch this.Kind() {
+		case Number:
+			number, err := strconv.Atoi(this.Value())
+			if err != nil { return nil, err }
+			list = append(list, ValueNumber(number))
+		case Color:
+			color, ok := parseColor([]rune(this.Value()))
+			if !ok {
+				return nil, parse.Errorf (
+					this.Pos(),
+					"malformed color literal")
+			}
+			list = append(list, ValueColor(color))
+		case String:
+			list = append(list, ValueString(this.Value()))
+		case Ident:
+			list = append(list, ValueKeyword(this.Value()))
+		case Dollar:
+			err := this.ExpectNext(Ident)
+			if err != nil { return nil, err }
+			list = append(list, ValueVariable(this.Value()))
+		case Slash:
+			list = append(list, ValueCut { })
+		}
+		this.Next()
+	}
+	return list, nil
+}
+
+func parseColor (runes []rune) (uint32, bool) {
+	digits := make([]uint32, len(runes))
+	for index, run := range runes {
+		digit := hexDigit(run)
+		if digit < 0 { return 0, false }
+		digits[index] = uint32(digit)
+	}
+	switch len(runes) {
+	case 3:
+		return  digits[0] << 28 | digits[0] << 24 |
+			digits[1] << 20 | digits[1] << 16 |
+			digits[2] << 12 | digits[2] <<  8 | 0xFF, true
+	case 6:
+		return  digits[0] << 28 | digits[1] << 24 |
+			digits[2] << 20 | digits[3] << 16 |
+			digits[4] << 12 | digits[5] <<  8 | 0xFF, true
+	case 4:
+		return  digits[0] << 28 | digits[0] << 24 |
+			digits[1] << 20 | digits[1] << 16 |
+			digits[2] << 12 | digits[2] <<  8 |
+			digits[3] <<  4 | digits[3] <<  0, true
+	case 8:
+		return  digits[0] << 28 | digits[1] << 24 |
+			digits[2] << 20 | digits[3] << 16 |
+			digits[4] << 12 | digits[5] <<  8 |
+			digits[6] <<  4 | digits[7] <<  0, true
+	default: return 0, false
+	}
+}
+
+func hexDigit (digit rune) int {
+	switch {
+	case digit >= '0' && digit <= '9': return int(digit - '0')
+	case digit >= 'a' && digit <= 'f': return int(digit - 'a') + 10
+	case digit >= 'A' && digit <= 'F': return int(digit - 'A') + 10
+	default: return -1
+	}
+}

internal/styles/tss/tss.go

@@ -0,0 +1,81 @@
+package tss
+
+import "os"
+import "git.tebibyte.media/tomo/tomo/event"
+import "git.tebibyte.media/tomo/backend/style"
+
+type Sheet struct {
+	Path      string
+	Variables map[string] ValueList
+	Rules     []Rule
+	flat      bool
+}
+
+type Rule struct {
+	Selector Selector
+	Attrs    map[string] []ValueList
+}
+
+type Selector struct {
+	Package string
+	Object  string
+	Tags    []string
+}
+
+type ValueList []Value
+
+type Value interface {
+	value ()
+}
+
+type ValueNumber int
+func (ValueNumber) value () { }
+
+type ValueColor uint32
+func (ValueColor) value () { }
+func (value ValueColor) RGBA () (r, g, b, a uint32) {
+	// extract components
+	bits := uint32(value)
+	r = (bits & 0xFF000000) >> 24
+	g = (bits & 0x00FF0000) >> 16
+	b = (bits & 0x0000FF00) >> 8
+	a = (bits & 0x000000FF)
+	// extend to 16 bits per channel
+	r = r << 8 | r
+	g = g << 8 | g
+	b = b << 8 | b
+	a = a << 8 | a
+	// alpha premultiply
+	r = (r * a) / 0xFFFF
+	g = (g * a) / 0xFFFF
+	b = (b * a) / 0xFFFF
+	return
+}
+
+type ValueString string
+func (ValueString) value () { }
+
+type ValueKeyword string
+func (ValueKeyword) value () { }
+
+type ValueVariable string
+func (ValueVariable) value () { }
+
+type ValueCut struct { }
+func (ValueCut) value () { }
+
+// LoadFile loads the stylesheet from the specified file. This may return a
+// parse.Error, so use parse.Format to print it.
+func LoadFile (name string) (*style.Style, event.Cookie, error) {
+	// TODO check cache for gobbed sheet. if the cache is nonexistent or
+	// invalid, then open/load/cache.
+	
+	file, err := os.Open(name)
+	if err != nil { return nil, nil, err }
+	defer file.Close()
+
+	sheet, err := Parse(Lex(name, file))
+	if err != nil { return nil, nil, err }
+	sheet.Path = name
+	return BuildStyle(sheet)
+}

internal/styles/tss/tss.yaml

@@ -0,0 +1,35 @@
+# Happen to use Micro to edit text?
+# Drop this in ~/.config/micro/syntax and get syntax highlighting for TSS files!
+
+filetype: tss
+
+detect:
+        filename: "\\.tss$"
+
+rules:
+        - type: "\\b([A-Z][a-zA-Z0-9]*).*:"
+        - identifier.var: "\\$[a-zA-Z0-9]*\\b"
+        - identifier.class: "(\\*|[a-z][a-zA-Z0-9]*)\\.(\\*|[A-Z][a-zA-Z0-9]*)"
+        - constant: "\\b(tile|center)\\b"
+        - constant: "\\b(start|middle|end|even)\\b"
+        - constant.bool: "\\b(true|false)\\b"
+        - special: "(\\/|,|\\;|:|\\.)"
+        - symbol.operator: "(=|\\*)"
+        - symbol.brackets: "(\\{\\[|\\}\\])"
+
+        - comment:
+                start: "//"
+                end: "$"
+                rules:
+                        - todo: "(TODO|XXX|FIXME|BUG):?"
+        
+        - constant.string:
+                start: "\""
+                end: "\""
+                skip: "\\\\."
+                rules:
+                        - constant.specialChar: "\\\\[abfnrtv'\\\"\\\\]"
+                        - constant.specialChar: "\\\\([0-7]{3})"
+
+        - constant.number: "\\b[0-9][0-9.]*\\b"
+        - constant.string: "\\B#[0-9a-fA-F]*"

internal/util/util.go

@@ -0,0 +1,10 @@
+package util
+
+import "git.tebibyte.media/tomo/tomo/data"
+
+func GeneralizeXDGIconMimeType (mime data.Mime) data.Mime {
+	// FIXME make this more accurate
+	// https://specifications.freedesktop.org/icon-naming-spec/icon-naming-spec-latest.html
+	mime.Subtype = "x-generic"
+	return mime
+}

manager.go

@@ -0,0 +1,33 @@
+package nasin
+
+import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/event"
+
+var manager struct {
+	count int
+}
+
+type funcCookie func ()
+func (cookie funcCookie) Close () {
+	cookie()
+}
+
+// WaitFor ensures that the application will stay running while the given window
+// is open.
+func WaitFor (window tomo.Window) event.Cookie {
+	manager.count ++
+	
+	isManaged := true
+	handleClose := func () {
+		if !isManaged { return }
+		isManaged = false
+		manager.count --
+		if manager.count < 1 {
+			tomo.Stop()
+		}
+	}
+
+	return event.MultiCookie (
+		window.OnClose(handleClose),
+		funcCookie(handleClose))
+}

path.go

@@ -10,12 +10,28 @@ func ApplicationUserDataDir (app ApplicationDescription) (string, error) {
 	return userMkdirAll(app.ID, userDataDir)
 }
 
+// ApplicationSystemDataDirs returns a list of directory paths where an
+// application can look for its system-level data files. Directories returned
+// by this function may or may not actually exist. This function may return an
+// empty slice on some platforms.
+func ApplicationSystemDataDirs (app ApplicationDescription) ([]string, error) {
+	return systemDirs(app.ID, systemDataDirs)
+}
+
 // ApplicationUserConfigDir returns the directory path where an application can
 // store its user configuration files.
 func ApplicationUserConfigDir (app ApplicationDescription) (string, error) {
 	return userMkdirAll(app.ID, userConfigDir)
 }
 
+// ApplicationSystemDataDirs returns a list of directory paths where an
+// application can look for its system-level configuration files. Directories
+// returned by this function may or may not actually exist. This function may
+// return an empty slice on some platforms.
+func ApplicationSystemConfigDirs (app ApplicationDescription) ([]string, error) {
+	return systemDirs(app.ID, systemConfigDirs)
+}
+
 // ApplicationUserCacheDir returns the directory path where an application can
 // store its user cache files.
 func ApplicationUserCacheDir (app ApplicationDescription) (string, error) {
@@ -30,3 +46,13 @@ func userMkdirAll (sub string, getter func () (string, error)) (string, error) {
 	if err != nil { return "", err }
 	return path, nil
 }
+
+func systemDirs (sub string, getter func () ([]string, error)) ([]string, error) {
+	paths, err := getter()
+	if err != nil { return nil, err }
+	specificPaths := make([]string, len(paths))
+	for index, path := range paths {
+		specificPaths[index] = filepath.Join(path, sub)
+	}
+	return specificPaths, nil
+}

path_unix.go

@@ -7,10 +7,18 @@ func userDataDir () (string, error) {
 	return basedir.DataHome()
 }
 
+func systemDataDirs () ([]string, error) {
+	return basedir.DataDirs()
+}
+
 func userConfigDir () (string, error) {
 	return basedir.ConfigHome()
 }
 
+func systemConfigDirs () ([]string, error) {
+	return basedir.ConfigDirs()
+}
+
 func userCacheDir () (string, error) {
 	return basedir.CacheHome()
 }