Update backend

application.go

@@ -65,6 +65,15 @@ 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 == "" {
@@ -119,8 +128,9 @@ func (role ApplicationRole) Icon () tomo.Icon {
 	}
 }
 
-// RunApplication is like tomo.Run, but runs an application. If something fails
-// to initialize, an error is written to the standard logger.
+// RunApplication is like tomo.Run, but runs an application. It automatically
+// sets up a backend. If something fails to initialize, an error is written to
+// the standard logger.
 func RunApplication (application Application) {
 	// TODO: see #4
 
@@ -129,19 +139,22 @@ func RunApplication (application Application) {
 	}
 	flag.Parse()
 
-	err := registrar.RegisterBackend()
+	reg := new(registrar.Registrar)
+	backend, err := reg.SetBackend()
 	if err != nil { log.Fatalln("nasin: could not register backend:", err) }
-	err = tomo.Run(func () {
-		err := registrar.SetTheme()
-		err := registrar.SetIconSet()
+	err = reg.SetTheme()
 	if err != nil { log.Fatalln("nasin: could not set theme:", err) }
+	err = reg.SetIconSet()
+	if err != nil { log.Fatalln("nasin: could not set icon set:", err) }
+	err = reg.SetFaceSet()
+	if err != nil { log.Fatalln("nasin: could not set face set:", err) }
 	err = application.Init()
 	if err != nil { log.Fatalln("nasin: could not run application:", err) }
 
 	// open URLs
 	args := flag.Args()
 	applicationOpenUrls(application, args...)
-	})
+	err = backend.Run()
 	if err != nil { log.Fatalln("nasin: could not run application:", err) }
 }
 

go.mod

@@ -4,9 +4,9 @@ go 1.22.2
 
 require (
 	git.tebibyte.media/sashakoshka/goparse v0.2.0
-	git.tebibyte.media/tomo/backend v0.5.1
-	git.tebibyte.media/tomo/objects v0.20.1
-	git.tebibyte.media/tomo/tomo v0.41.1
+	git.tebibyte.media/tomo/backend v0.6.1
+	git.tebibyte.media/tomo/objects v0.21.0
+	git.tebibyte.media/tomo/tomo v0.45.0
 	git.tebibyte.media/tomo/xdg v0.1.0
 	golang.org/x/image v0.11.0
 )

go.sum

@@ -1,12 +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 v0.5.1 h1:u3DLVcNWNdQsIxAEGcZ+kGG7zuew8tpPbyEFBx8ehjM=
-git.tebibyte.media/tomo/backend v0.5.1/go.mod h1:urnfu+D56Q9AOCZ/qp5YqkmlRRTIB5p9RbzBN7yIibQ=
-git.tebibyte.media/tomo/objects v0.20.1 h1:dCMMzaHmj7w016XtTb8QWvKMHVK2Fru/2a70NqApzHQ=
-git.tebibyte.media/tomo/objects v0.20.1/go.mod h1:hbBlQem9cNOt/G2rBvH/C94FT1oWgbtEftwg6ield9U=
-git.tebibyte.media/tomo/tomo v0.41.1 h1:XdbyF3VjsLj1Zppr70gUaufuh49hU32JQo2ENnw4PcA=
-git.tebibyte.media/tomo/tomo v0.41.1/go.mod h1:C9EzepS9wjkTJjnZaPBh22YvVPyA4hbBAJVU20Rdmps=
+git.tebibyte.media/tomo/backend v0.6.1 h1:TVbvfbcMrF8YAVGsXPQNQLCam3xuOWJmZA0B+op0ig0=
+git.tebibyte.media/tomo/backend v0.6.1/go.mod h1:7gl0Z1V8Vcns41pXIpQt1FYlANrQf5bCboxMjTCCrgc=
+git.tebibyte.media/tomo/objects v0.21.0 h1:exFbzQPQhGIVQK5BCDg69ZV96zMamV50G4GRsnK+yfA=
+git.tebibyte.media/tomo/objects v0.21.0/go.mod h1:ljnNcCuNfvcYLHmQrEU7LuG0OvQiAVDCXU+ajspq+TI=
+git.tebibyte.media/tomo/tomo v0.45.0 h1:fQH0WIPidW275hOq9dE6R7p064xG1RGx2QU68Avlr84=
+git.tebibyte.media/tomo/tomo v0.45.0/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=

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

@@ -7,6 +7,7 @@ import _ "image/png"
 import "git.tebibyte.media/tomo/tomo"
 import "git.tebibyte.media/tomo/tomo/data"
 import "git.tebibyte.media/tomo/tomo/canvas"
+import "git.tebibyte.media/tomo/backend/style"
 
 //go:embed assets/icons-small.png
 var atlasSmallBytes []byte
@@ -411,23 +412,23 @@ func generateSource (data []byte, width int) map[tomo.Icon] canvas.Texture {
 	return source
 }
 
-type iconTheme struct {
+type iconSet struct {
 	texturesSmall map[tomo.Icon] canvas.Texture
 	texturesLarge map[tomo.Icon] canvas.Texture
 }
 
-// New creates a new fallback icon theme.
-func New () tomo.IconSet {
-	return new(iconTheme)
+// New creates a new fallback icon set.
+func New () style.IconSet {
+	return new(iconSet)
 }
 
-func (this *iconTheme) ensure () {
+func (this *iconSet) ensure () {
 	if this.texturesSmall != nil { return }
 	this.texturesSmall = generateSource(atlasSmallBytes, 16)
 	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 +436,7 @@ 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 {
@@ -444,7 +445,7 @@ 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 mime == data.M("inode", "directory") {

internal/icons/xdg/icon.go

@@ -8,19 +8,20 @@ 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/canvas"
+import "git.tebibyte.media/tomo/backend/style"
+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
 	texturesMedium map[tomo.Icon] canvas.Texture
 	texturesLarge  map[tomo.Icon] canvas.Texture
 }
 
-func FindThemeWarn (name string, fallback tomo.IconSet, path ...string) (tomo.IconSet, error) {
+func FindThemeWarn (name string, fallback style.IconSet, path ...string) (style.IconSet, error) {
 	this := &iconTheme {
 		fallback:       fallback,
 		texturesLarge:  make(map[tomo.Icon] canvas.Texture),

internal/registrar/registrar_unix.go

@@ -5,35 +5,45 @@ import "os"
 import "log"
 import "git.tebibyte.media/tomo/tomo"
 import "git.tebibyte.media/tomo/backend/x"
+import "git.tebibyte.media/sashakoshka/goparse"
 import "git.tebibyte.media/tomo/nasin/internal/icons/xdg"
-import "git.tebibyte.media/tomo/nasin/internal/style/tss"
+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/faces/fallback"
 
-func RegisterBackend () error {
-	tomo.Register(1, x.New)
-	return nil
+type Registrar struct {
+	backend *x.Backend
 }
 
-func SetTheme () error {
-	// TODO eventually get rid of this when we make a file format for
-	// storing visual styles
+func (this *Registrar) SetBackend () (tomo.Backend, error) {
+	backend, err := x.New()
+	if err != nil { return nil, err }
+	this.backend = backend.(*x.Backend)
+	tomo.SetBackend(backend)
+	return backend, nil
+}
+
+func (this *Registrar) SetTheme () error {
 	styleSheetName := os.Getenv("TOMO_STYLE_SHEET")
 	if styleSheetName != "" {
 		styl, _, err := tss.LoadFile(styleSheetName)
 		if err == nil {
-			tomo.SetStyle(styl)
+			this.backend.SetStyle(styl)
+			return nil
 		} else {
-			log.Printf("nasin: could not load style sheet '%s': %v", styleSheetName, err)
+			log.Printf (
+				"nasin: could not load style sheet '%s'\n%v",
+				styleSheetName, parse.Format(err))
 		}
 	}
 	
 	styl, _ := fallbackStyle.New()
-	tomo.SetStyle(styl)
+	this.backend.SetStyle(styl)
 	return nil
 }
 
-func SetIconSet () error {
+func (this *Registrar) SetIconSet () error {
 	iconSet := fallbackIcons.New()
 	iconSetName := os.Getenv("TOMO_XDG_ICON_THEME")
 	if iconSetName != "" {
@@ -45,6 +55,14 @@ func SetIconSet () error {
 		}
 	}
 	
-	tomo.SetIconSet(iconSet)
+	this.backend.SetIconSet(iconSet)
+	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/tss/tss.go

@@ -1,21 +0,0 @@
-package tss
-
-import "io"
-import "os"
-import "git.tebibyte.media/tomo/tomo"
-import "git.tebibyte.media/tomo/tomo/event"
-
-func BuildStyle (sheet Sheet) (*tomo.Style, event.Cookie, error) {
-	// TODO
-	return nil, nil, nil
-}
-
-func LoadFile (name string) (*tomo.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()
-	return Load(file)
-}

internal/styles/aluminum/aluminum.tss

@@ -0,0 +1,215 @@
+// 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        = $ColorOutline                   / 1;
+$BorderEngraved       = #c3c3c5 #e3e3e3 #e9e9e9 #c2c2c2 / 1;
+$BorderGap            = #697c7c #566767 #566767 #697c7c / 1;
+$BorderLifted         = #f9fafc #c2c8d3 #a4afc0 #f5f6f8 / 1;
+$BorderLiftedFocused  = #f0f4f9 #b1baca #9aa6b7 #e4e9ee / 1;
+$BorderFocused        = #5f8bc4 #5f8bc4 #5f8bc4 #5f8bc4 / 1;
+$BorderTear           = $BorderEngraved;
+$BorderTearFocused    = #7f94b5 #ced7e4 #ced7e4 #7f94b5 / 1;
+$BorderTearPad        = #0000                           / 3;
+$BorderTearPadFocused = #7391c080                       / 3;
+$BorderInnerShadow    = #a4afc0                         / 1 0 0 1;
+$BorderOuterShadow    = #a4afc0                         / 0 1 1 0;
+
+*.* {
+	TextColor: $ColorForeground;
+	DotColor:  $ColorDot;
+	Gap:       8;
+}
+
+*.Button {
+	Border:  $BorderEngraved, $BorderGap, $BorderLifted;
+	Padding: 4 8;
+	Color:   $ColorRaised;
+}
+
+*.Button[focused] {
+	Border:  $BorderEngraved, $BorderGap, $BorderLiftedFocused;
+	Padding: 4 8;
+	Color:   $ColorRaisedFocused;
+}
+
+*.Button[hovered] {
+	Color: $ColorRaisedHovered;
+}
+
+*.Button[pressed] {
+	Border:  $BorderEngraved, $BorderGap, $BorderInnerShadow;
+	Padding: 5 8 4 9;
+	Color:   $ColorRaisedPressed;
+}
+
+*.TextInput {
+	Border:  $BorderEngraved, $BorderGap, $BorderInnerShadow;
+	Padding: 5 4 4 5;
+	Color:   $ColorSunken;
+}
+
+*.TextInput[focused] {
+	Border: $BorderEngraved, $BorderFocused, $BorderInnerShadow;
+}
+
+*.TextView {
+	Border:  $BorderEngraved, $BorderGap, $BorderInnerShadow;
+	Padding: 5 4 4 5;
+	Color:   $ColorSunken;
+}
+
+*.NumberInput {
+	Gap: 0;
+}
+
+*.Container[sunken] {
+	Border:  $BorderEngraved, $BorderGap, $BorderInnerShadow;
+	Padding: 5 4 4 5;
+	Color:   $ColorSunken;
+}
+
+*.Container[outer] {
+	Color:   $ColorBackground;
+	Padding: 8;
+}
+
+*.Container[menu] {
+	Border: $BorderGap, $BorderLifted;
+	Color:  $ColorBackground;
+	Gap:    0;
+}
+
+*.Heading {
+	Align: middle middle;
+}
+
+*.Separator {
+	Border: $BorderEngraved;
+}
+
+*.Slider {
+	Border: $BorderEngraved, $BorderGap, $BorderInnerShadow;
+	Color:  $ColorGutter;
+}
+
+*.Slider[focused] {
+	Border: $BorderEngraved, $BorderFocused, $BorderInnerShadow;
+}
+
+*.Slider[hovered] {
+	Color: $ColorGutterHovered;
+}
+
+*.Slider[horizontal] {
+	MinimumSize: 48 0;
+}
+
+*.Slider[vertical] {
+	MinimumSize: 0 48;
+}
+
+*.SliderHandle {
+	Border:      $BorderOuterShadow, $BorderGap, $BorderLifted;
+	Color:       $ColorRaised;
+	MinimumSize: 12;
+}
+
+*.ScrollContainer {
+	Gap: 0;
+}
+
+*.Checkbox {
+	Border:      $BorderEngraved, $BorderGap, $BorderInnerShadow;
+	Color:       $ColorSunken;
+	Padding:     0 1 1 0;
+	MinimumSize: 19;
+}
+
+*.Checkbox[focused] {
+	Border:  $BorderEngraved, $BorderFocused, $BorderInnerShadow;
+	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, $BorderTear;
+}
+
+*.TearLine[hovered] {
+	Border: $BorderTearPadFocused, $BorderTearFocused;
+}
+
+*.TearLine[focused] {
+	Border: $BorderTearPadFocused, $BorderTearFocused;
+}
+
+*.Calendar {
+	Border:  $BorderOuterShadow, $BorderGap;
+	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;
+}

internal/styles/fallback/wintergreen.go

@@ -7,8 +7,8 @@ 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 }
@@ -55,7 +55,7 @@ func newCloserCookie (closer io.Closer) event.Cookie {
 
 // New returns Wintergreen, the default Tomo style. It is neutral-gray with
 // green and turquoise accents.
-func New () (*tomo.Style, event.Cookie) {
+func New () (*style.Style, event.Cookie) {
 	atlasImage, _, err := image.Decode(bytes.NewReader(atlasBytes))
 	if err != nil { panic(err) }
 	atlasTexture := tomo.NewTexture(atlasImage)
@@ -68,17 +68,16 @@ func New () (*tomo.Style, event.Cookie) {
 
 	cookie := event.MultiCookie(newCloserCookie(atlasTexture))
 
-rules := []tomo.Rule {
+rules := []style.Rule {
 	// *.*
-	tomo.Ru(tomo.AS (
-		tomo.AFace      (basicfont.Face7x13  ),
+	style.Ru(style.AS (
 		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 {
@@ -91,7 +90,7 @@ rules := []tomo.Rule {
 	), tomo.R("", "Button")),
 
 	// *.Button[focused]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			outline,
 			tomo.Border {
@@ -102,7 +101,7 @@ rules := []tomo.Rule {
 	), tomo.R("", "Button"), "focused"),
 	
 	// *.Button[pressed]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			outline,
 			tomo.Border {
@@ -115,7 +114,7 @@ rules := []tomo.Rule {
 	), tomo.R("", "Button"), "pressed"),
 
 	// *.TextInput
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.ABorder (
 			outline,
 			tomo.Border {
@@ -127,7 +126,7 @@ rules := []tomo.Rule {
 	), tomo.R("", "TextInput")),
 
 	// *.TextInput[focused]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.ABorder (
 			outline,
 			tomo.Border {
@@ -137,7 +136,7 @@ rules := []tomo.Rule {
 	), tomo.R("", "TextInput"), "focused"),
 	
 	// *.TextView
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.ABorder (
 			outline,
 			tomo.Border {
@@ -149,12 +148,12 @@ 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.ABorder (
 			outline,
 			tomo.Border {
@@ -167,13 +166,13 @@ rules := []tomo.Rule {
 	), 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 {
@@ -186,12 +185,12 @@ 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")),
 
 	// *.Separator
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			tomo.Border {
 				Width: tomo.I(1),
@@ -201,7 +200,7 @@ rules := []tomo.Rule {
 	), tomo.R("", "Separator")),
 
 	// *.Slider
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			outline,
 			tomo.Border {
@@ -214,7 +213,7 @@ rules := []tomo.Rule {
 	), tomo.R("", "Slider")),
 	
 	// *.Slider[focused]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.ABorder (
 			outline,
 			tomo.Border {
@@ -225,17 +224,17 @@ rules := []tomo.Rule {
 	), 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.ABorder (
 			outline,
 			tomo.Border {
@@ -255,17 +254,17 @@ rules := []tomo.Rule {
 	), tomo.R("", "SliderHandle")),
 
 	// *.SliderHandle[horizontal]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.ATexture(textureHandleHorizontal),
 	), tomo.R("", "SliderHandle"), "horizontal"),
 
 	// *.ScrollContainer
-	tomo.Ru(tomo.AS (
+	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 {
@@ -280,7 +279,7 @@ rules := []tomo.Rule {
 	), tomo.R("", "Checkbox")),
 
 	// *.Checkbox[focused]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.ABorder (
 			outline,
 			tomo.Border {
@@ -291,39 +290,39 @@ rules := []tomo.Rule {
 	), tomo.R("", "Checkbox"), "focused"),
 
 	// *.Checkbox[checked]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		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.ABorder (
 			tomo.Border {
 				Width: tomo.I(3),
@@ -339,7 +338,7 @@ rules := []tomo.Rule {
 	), tomo.R("", "TearLine")),
 
 	// *.TearLine[focused]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			tomo.Border {
 				Width: tomo.I(3),
@@ -349,7 +348,7 @@ 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),
@@ -359,7 +358,7 @@ 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),
@@ -373,37 +372,37 @@ 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),
@@ -420,7 +419,7 @@ 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),
@@ -435,7 +434,7 @@ 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),
@@ -461,7 +460,7 @@ 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),
@@ -488,7 +487,7 @@ 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),
@@ -504,7 +503,7 @@ rules := []tomo.Rule {
 	), tomo.R("", "Tab"), "active"),
 
 	// *.Swatch
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			outline,
 		},
@@ -512,7 +511,7 @@ rules := []tomo.Rule {
 	), tomo.R("", "Swatch")),
 
 	// *.Swatch[focused]
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			outline,
 			tomo.Border {
@@ -523,7 +522,7 @@ rules := []tomo.Rule {
 	), tomo.R("", "Swatch"), "focused"),
 
 	// *.ColorPickerMap
-	tomo.Ru(tomo.AS (
+	style.Ru(style.AS (
 		tomo.AttrBorder {
 			outline,
 			tomo.Border {
@@ -536,7 +535,7 @@ rules := []tomo.Rule {
 	), tomo.R("", "ColorPickerMap")),
 }
 
-	return &tomo.Style {
+	return &style.Style {
 		Rules: rules,
 		Colors: map[tomo.Color] color.Color {
 			tomo.ColorBackground: colorBackground,

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

@@ -19,6 +19,7 @@ const (
 	Star
 	Dot
 	Dollar
+	Slash
 	Color
 	Ident
 	Number
@@ -39,6 +40,7 @@ var tokenNames = map[parse.TokenKind] string {
 	Star: "Star",
 	Dot: "Dot",
 	Dollar: "Dollar",
+	Slash: "Slash",
 	Color: "Color",
 	Ident: "Ident",
 	Number: "Number",
@@ -115,6 +117,8 @@ func (this *lexer) next () (token parse.Token, err error) {
 				skipRune()
 				if err != nil { return }
 			}
+		} else {
+			token.Kind = Slash
 		}
 		if this.eof { err = nil; return }
 

internal/styles/tss/parse.go

@@ -4,43 +4,6 @@ import "io"
 import "strconv"
 import "git.tebibyte.media/sashakoshka/goparse"
 
-type Sheet struct {
-	Variables map[string] ValueList
-	Rules     []Rule
-}
-
-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 ()
-}
-
-func (ValueNumber) value () { }
-type ValueNumber int
-
-func (ValueColor) value () { }
-type ValueColor uint32
-
-func (ValueString) value () { }
-type ValueString string
-
-func (ValueKeyword) value () { }
-type ValueKeyword string
-
-func (ValueVariable) value () { }
-type ValueVariable string
-
 type parser struct {
 	parse.Parser
 	sheet Sheet
@@ -105,9 +68,9 @@ func (this *parser) parseVariable () (string, ValueList, error) {
 	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 }
-	name := this.Value()
 	this.Next()
 	values, err := this.parseValueList()
 	if err != nil { return "", nil, err }
@@ -124,15 +87,18 @@ func (this *parser) parseRule () (Rule, error) {
 	selector, err := this.parseSelector()
 	if err != nil { return Rule { }, err }
 	rule.Selector = selector
-	err = this.Expect(LBracket)
+	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 { break }
-		_, exists := rule.Attrs[name]
-		if !exists {
+		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",
@@ -141,8 +107,6 @@ func (this *parser) parseRule () (Rule, error) {
 		rule.Attrs[name] = attr
 	}
 	
-	err = this.Expect(LBracket)
-	if err != nil { return Rule { }, err }
 	return rule, this.Next()
 }
 
@@ -167,20 +131,22 @@ func (this *parser) parseSelector () (Selector, error) {
 	}
 
 	// tags
-	err = this.ExpectNext(LBrace)
+	err = this.ExpectNext(LBracket)
 	if err == nil {
 		this.Next()
 		for {
-			err := this.Expect(Ident, String, RBrace)
+			err := this.Expect(Ident, String, RBracket)
 			if err != nil { return Selector { }, err }
-			if this.Is(RBrace) { break }
+			if this.Is(RBracket) { break       }
+			if this.Is(Comma)    { this.Next() }
 			selector.Tags = append(selector.Tags, this.Value())
-			err = this.ExpectNext(Comma, RBrace)
+			err = this.ExpectNext(Comma, RBracket)
 			if err != nil { return Selector { }, err }
 		}
+		this.Next()
 	}
 	
-	return selector, this.Next()
+	return selector, nil
 }
 
 func (this *parser) parseAttr () (string, []ValueList, error) {
@@ -195,18 +161,20 @@ func (this *parser) parseAttr () (string, []ValueList, error) {
 	this.Next()
 	for {
 		err := this.ExpectDesc (
-			"value, comma, or semicolon",
-			Number, Color, String, Ident, Dollar, Comma, Semicolon)
+			"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.ExpectNext(Comma, Semicolon)
+		err = this.Expect(Comma, Semicolon)
 		if err != nil { return "", nil, err }
 	}
 	
-	return name, attr, this.Next()
+	return name, attr, nil
 }
 
 func (this *parser) parseValueList () (ValueList, error) {
@@ -214,7 +182,7 @@ func (this *parser) parseValueList () (ValueList, error) {
 	for {
 		err := this.ExpectDesc (
 			"value",
-			Number, Color, String, Ident, Dollar)
+			Number, Color, String, Ident, Dollar, Slash)
 		if err != nil { break }
 		switch this.Kind() {
 		case Number:
@@ -237,9 +205,12 @@ func (this *parser) parseValueList () (ValueList, error) {
 			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, this.Next()
+	return list, nil
 }
 
 func parseColor (runes []rune) (uint32, bool) {

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]*"