build(markdown): add no_syntax_highlighting tag to build without chroma (#849)

.github/workflows/ci.yml

@@ -53,7 +53,7 @@ jobs:
       - name: Test
         run: |
           go test ${{ matrix.os != 'windows-11-arm' && '-race' || '' }} -v ./...
-          go test ${{ matrix.os != 'windows-11-arm' && '-race' || '' }} -v -tags no_spoof_tls_fingerprint,no_voice ./...
+          go test ${{ matrix.os != 'windows-11-arm' && '-race' || '' }} -v -tags no_spoof_tls_fingerprint,no_voice,no_syntax_highlighting ./...
 
       - name: Build
         run: go build -trimpath -ldflags=-s .

README.md

@@ -40,6 +40,7 @@ go build .
 
 - `no_voice` to build without voice support.
 - `no_spoof_tls_fingerprint` to build without TLS fingerprint spoofing.
+- `no_syntax_highlighting` to build without syntax highlighting in code blocks.
 
 ## Usage
 

internal/markdown/highlight.go

@@ -0,0 +1,85 @@
+//go:build !no_syntax_highlighting
+
+package markdown
+
+import (
+	"github.com/alecthomas/chroma/v2"
+	"github.com/alecthomas/chroma/v2/lexers"
+	"github.com/alecthomas/chroma/v2/styles"
+	"github.com/ayn2op/tview"
+	"github.com/gdamore/tcell/v3"
+)
+
+func (r *Renderer) writeCodeBlock(builder *Builder, code string, language string, base tview.Style) {
+	lexer := lexers.Get(language)
+	declaredLanguageSupported := lexer != nil
+
+	// Detect the language from its content.
+	var analyzed bool
+	if lexer == nil {
+		lexer = lexers.Analyse(code)
+		analyzed = lexer != nil
+	}
+	if lexer == nil {
+		lexer = lexers.Fallback
+	}
+
+	// Some lexers emit many tiny tokens; coalesce runs of the same type.
+	lexer = chroma.Coalesce(lexer)
+
+	var header string
+	switch {
+	case analyzed:
+		header = "code: analyzed"
+	case language == "":
+		header = "code"
+	case !declaredLanguageSupported:
+		header = "code: " + language
+	}
+	if header != "" {
+		builder.Write(codeBlockIndent+header, base.Dim(true))
+		builder.NewLine()
+	}
+
+	iterator, err := lexer.Tokenise(nil, code)
+	if err != nil {
+		builder.Write(codeBlockIndent, base)
+		writeCode(builder, code, base, base)
+		return
+	}
+
+	theme := styles.Get(r.cfg.Markdown.Theme)
+	if theme == nil {
+		theme = styles.Fallback
+	}
+
+	builder.Write(codeBlockIndent, base)
+	for token := iterator(); token != chroma.EOF; token = iterator() {
+		style := applyChromaStyle(base, theme.Get(token.Type))
+		writeCode(builder, token.Value, style, base)
+	}
+}
+
+func applyChromaStyle(base tview.Style, entry chroma.StyleEntry) tview.Style {
+	style := base
+	if entry.Colour.IsSet() {
+		style = style.Foreground(tcell.NewRGBColor(
+			int32(entry.Colour.Red()),
+			int32(entry.Colour.Green()),
+			int32(entry.Colour.Blue()),
+		))
+	}
+	// Token background colors are not applied, so code blocks keep the user's terminal/chat background.
+
+	// An attribute chroma passes on is left as it is.
+	if entry.Bold != chroma.Pass {
+		style = style.Bold(entry.Bold == chroma.Yes)
+	}
+	if entry.Italic != chroma.Pass {
+		style = style.Italic(entry.Italic == chroma.Yes)
+	}
+	if entry.Underline != chroma.Pass {
+		style = style.Underline(entry.Underline == chroma.Yes)
+	}
+	return style
+}

internal/markdown/highlight_none.go

@@ -0,0 +1,17 @@
+//go:build no_syntax_highlighting
+
+package markdown
+
+import "github.com/ayn2op/tview"
+
+func (r *Renderer) writeCodeBlock(builder *Builder, code string, language string, base tview.Style) {
+	header := "code"
+	if language != "" {
+		header += ": " + language
+	}
+	builder.Write(codeBlockIndent+header, base.Dim(true))
+	builder.NewLine()
+
+	builder.Write(codeBlockIndent, base)
+	writeCode(builder, code, base, base)
+}

internal/markdown/renderer.go

@@ -4,14 +4,10 @@ import (
 	"strconv"
 	"strings"
 
-	"github.com/alecthomas/chroma/v2"
-	"github.com/alecthomas/chroma/v2/lexers"
-	"github.com/alecthomas/chroma/v2/styles"
 	md "github.com/ayn2op/arikawa/v3/markdown"
 	"github.com/ayn2op/discordo/internal/config"
 	"github.com/ayn2op/tview"
 	"github.com/ayn2op/tview/text"
-	"github.com/gdamore/tcell/v3"
 	"github.com/yuin/goldmark/v2/ast"
 )
 
@@ -124,69 +120,23 @@ func (r *Renderer) RenderText(source []byte, node ast.Node, base tview.Style, em
 
 func (r *Renderer) renderCodeBlock(builder *Builder, source []byte, node *ast.CodeBlock, base tview.Style) {
 	var code strings.Builder
-	lines := node.Value.Segments()
-	for _, line := range lines {
+	for _, line := range node.Value.Segments() {
 		code.Write(line.Bytes(source))
 	}
 
 	language, _ := node.Language(source)
-	language = strings.TrimSpace(language)
-	lexer := lexers.Get(language)
-	declaredLanguageSupported := lexer != nil
+	r.writeCodeBlock(builder, code.String(), strings.TrimSpace(language), base)
+}
 
-	// Detect the language from its content.
-	var analyzed bool
-	if lexer == nil {
-		lexer = lexers.Analyse(code.String())
-		analyzed = lexer != nil
-	}
-	if lexer == nil {
-		lexer = lexers.Fallback
-	}
-
-	// Some lexers emit many tiny tokens; coalesce runs of the same type.
-	lexer = chroma.Coalesce(lexer)
-
-	var header string
-	switch {
-	case analyzed:
-		header = "code: analyzed"
-	case language == "":
-		header = "code"
-	case !declaredLanguageSupported:
-		header = "code: " + language
-	}
-	if header != "" {
-		builder.Write(codeBlockIndent+header, base.Dim(true))
-		builder.NewLine()
-	}
-
-	iterator, err := lexer.Tokenise(nil, code.String())
-	if err != nil {
-		for _, line := range lines {
-			builder.Write(codeBlockIndent+string(line.Bytes(source)), base)
+// writeCode writes s in style, starting each line after the first with the code block indent in base.
+func writeCode(builder *Builder, s string, style, base tview.Style) {
+	for i, part := range strings.Split(s, "\n") {
+		if i > 0 {
+			builder.NewLine()
+			builder.Write(codeBlockIndent, base)
 		}
-		return
-	}
-
-	theme := styles.Get(r.cfg.Markdown.Theme)
-	if theme == nil {
-		theme = styles.Fallback
-	}
-
-	builder.Write(codeBlockIndent, base)
-	for token := iterator(); token != chroma.EOF; token = iterator() {
-		style := applyChromaStyle(base, theme.Get(token.Type))
-		// Chroma tokens may include embedded newlines, so split and re-emit with indentation on each visual line.
-		parts := strings.Split(token.Value, "\n")
-		for i, part := range parts {
-			if i > 0 {
-				builder.NewLine()
-				builder.Write(codeBlockIndent, base)
-			}
-			if part != "" {
-				builder.Write(part, style)
-			}
+		if part != "" {
+			builder.Write(part, style)
 		}
 	}
 }
@@ -210,30 +160,6 @@ func listMarker(item *ast.ListItem) string {
 	return strconv.Itoa(number) + ". "
 }
 
-func applyChromaStyle(base tview.Style, entry chroma.StyleEntry) tview.Style {
-	style := base
-	if entry.Colour.IsSet() {
-		style = style.Foreground(tcell.NewRGBColor(
-			int32(entry.Colour.Red()),
-			int32(entry.Colour.Green()),
-			int32(entry.Colour.Blue()),
-		))
-	}
-	// Token background colors are not applied, so code blocks keep the user's terminal/chat background.
-
-	// An attribute chroma passes on is left as it is.
-	if entry.Bold != chroma.Pass {
-		style = style.Bold(entry.Bold == chroma.Yes)
-	}
-	if entry.Italic != chroma.Pass {
-		style = style.Italic(entry.Italic == chroma.Yes)
-	}
-	if entry.Underline != chroma.Pass {
-		style = style.Underline(entry.Underline == chroma.Yes)
-	}
-	return style
-}
-
 func mentionText(node *md.Mention) string {
 	switch {
 	case node.Channel != nil: