Renamed style directory to styles

internal/styles/tss/build.go

@@ -0,0 +1,373 @@
+package tss
+
+import "fmt"
+import "image"
+import "errors"
+import "image/color"
+import "git.tebibyte.media/tomo/tomo"
+import "git.tebibyte.media/tomo/tomo/event"
+import "git.tebibyte.media/tomo/backend/style"
+
+type styleBuilder struct {
+	sheet Sheet
+}
+
+type faceKey struct {
+	name string
+	size int
+}
+
+// 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,
+	}
+	return builder.build()
+}
+
+func (this *styleBuilder) build () (*style.Style, event.Cookie, error) {
+	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 }
+	}
+	
+	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"),
+		},
+	}
+	
+	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
+	}
+
+	// TODO include all the faces in this.faces (ONCE EACH) in the
+	// multicookie
+	
+	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":
+		// TODO load image from file
+	
+	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 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
+	}
+}
+

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 +1,253 @@
+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 {
+		this.Next()
+		for {
+			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 }
+		}
+		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 +1,79 @@
+package tss
+
+import "os"
+import "git.tebibyte.media/tomo/tomo/event"
+import "git.tebibyte.media/tomo/backend/style"
+
+type Sheet struct {
+	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 }
+	return BuildStyle(sheet)
+}

internal/styles/tss/tss.yaml

@@ -0,0 +1,32 @@
+# 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]*)"
+        - 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]*"