Refactor markdown math render, add dollor-backquote syntax support

modules/markup/markdown/markdown.go

@@ -78,26 +78,23 @@ func (r *GlodmarkRender) Renderer() renderer.Renderer {
 
 func (r *GlodmarkRender) highlightingRenderer(w util.BufWriter, c highlighting.CodeBlockContext, entering bool) {
 	if entering {
-		language, _ := c.Language()
-		if language == nil {
-			language = []byte("text")
-		}
-
-		languageStr := string(language)
+		languageBytes, _ := c.Language()
+		languageStr := giteautil.IfZero(string(languageBytes), "text")
 
-		preClasses := []string{"code-block"}
+		preClasses := "code-block"
 		if languageStr == "mermaid" || languageStr == "math" {
-			preClasses = append(preClasses, "is-loading")
+			preClasses += " is-loading"
 		}
 
-		err := r.ctx.RenderInternal.FormatWithSafeAttrs(w, `<pre class="%s">`, strings.Join(preClasses, " "))
+		err := r.ctx.RenderInternal.FormatWithSafeAttrs(w, `<pre class="%s">`, preClasses)
 		if err != nil {
 			return
 		}
 
-		// include language-x class as part of commonmark spec
-		// the "display" class is used by "js/markup/math.js" to render the code element as a block
-		err = r.ctx.RenderInternal.FormatWithSafeAttrs(w, `<code class="chroma language-%s display">`, string(language))
+		// include language-x class as part of commonmark spec, "chroma" class is used to highlight the code
+		// the "display" class is used by "js/markup/math.ts" to render the code element as a block
+		// the "math.ts" strictly depends on the structure: <pre class="code-block is-loading"><code class="language-math display">...</code></pre>
+		err = r.ctx.RenderInternal.FormatWithSafeAttrs(w, `<code class="chroma language-%s display">`, languageStr)
 		if err != nil {
 			return
 		}
@@ -128,7 +125,12 @@ func SpecializedMarkdown(ctx *markup.RenderContext) *GlodmarkRender {
 				),
 				highlighting.WithWrapperRenderer(r.highlightingRenderer),
 			),
-			math.NewExtension(&ctx.RenderInternal, math.Enabled(setting.Markdown.EnableMath)),
+			math.NewExtension(&ctx.RenderInternal, math.Options{
+				Enabled:           setting.Markdown.EnableMath,
+				ParseDollarInline: true,
+				ParseDollarBlock:  true,
+				ParseSquareBlock:  true, // TODO: this is a bad syntax, it should be deprecated in the future (by some config options)
+			}),
 			meta.Meta,
 		),
 		goldmark.WithParserOptions(

modules/markup/markdown/markdown_math_test.go

@@ -12,8 +12,9 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+const nl = "\n"
+
 func TestMathRender(t *testing.T) {
-	const nl = "\n"
 	testcases := []struct {
 		testcase string
 		expected string
@@ -86,6 +87,18 @@ func TestMathRender(t *testing.T) {
 			`$\text{$b$}$`,
 			`<p><code class="language-math">\text{$b$}</code></p>` + nl,
 		},
+		{
+			"a$`b`$c",
+			`<p>a<code class="language-math">b</code>c</p>` + nl,
+		},
+		{
+			"a $`b`$ c",
+			`<p>a <code class="language-math">b</code> c</p>` + nl,
+		},
+		{
+			"a$``b``$c x$```y```$z",
+			`<p>a<code class="language-math">b</code>c x<code class="language-math">y</code>z</p>` + nl,
+		},
 	}
 
 	for _, test := range testcases {
@@ -215,6 +228,11 @@ x
 </ol>
 `,
 		},
+		{
+			"inline-non-math",
+			`\[x]`,
+			`<p>[x]</p>` + nl,
+		},
 	}
 
 	for _, test := range testcases {

modules/markup/markdown/math/block_parser.go

@@ -16,16 +16,18 @@ import (
 
 type blockParser struct {
 	parseDollars    bool
+	parseSquare     bool
 	endBytesDollars []byte
-	endBytesBracket []byte
+	endBytesSquare  []byte
 }
 
 // NewBlockParser creates a new math BlockParser
-func NewBlockParser(parseDollarBlocks bool) parser.BlockParser {
+func NewBlockParser(parseDollars, parseSquare bool) parser.BlockParser {
 	return &blockParser{
-		parseDollars:    parseDollarBlocks,
+		parseDollars:    parseDollars,
+		parseSquare:     parseSquare,
 		endBytesDollars: []byte{'$', '$'},
-		endBytesBracket: []byte{'\\', ']'},
+		endBytesSquare:  []byte{'\\', ']'},
 	}
 }
 
@@ -40,7 +42,7 @@ func (b *blockParser) Open(parent ast.Node, reader text.Reader, pc parser.Contex
 	var dollars bool
 	if b.parseDollars && line[pos] == '$' && line[pos+1] == '$' {
 		dollars = true
-	} else if line[pos] == '\\' && line[pos+1] == '[' {
+	} else if b.parseSquare && line[pos] == '\\' && line[pos+1] == '[' {
 		if len(line[pos:]) >= 3 && line[pos+2] == '!' && bytes.Contains(line[pos:], []byte(`\]`)) {
 			// do not process escaped attention block: "> \[!NOTE\]"
 			return nil, parser.NoChildren
@@ -53,10 +55,10 @@ func (b *blockParser) Open(parent ast.Node, reader text.Reader, pc parser.Contex
 	node := NewBlock(dollars, pos)
 
 	// Now we need to check if the ending block is on the segment...
-	endBytes := giteaUtil.Iif(dollars, b.endBytesDollars, b.endBytesBracket)
+	endBytes := giteaUtil.Iif(dollars, b.endBytesDollars, b.endBytesSquare)
 	idx := bytes.Index(line[pos+2:], endBytes)
 	if idx >= 0 {
-		// for case $$ ... $$ any other text
+		// for case: "$$ ... $$ any other text" (this case will be handled by the inline parser)
 		for i := pos + 2 + idx + 2; i < len(line); i++ {
 			if line[i] != ' ' && line[i] != '\n' {
 				return nil, parser.NoChildren
@@ -70,6 +72,13 @@ func (b *blockParser) Open(parent ast.Node, reader text.Reader, pc parser.Contex
 		return node, parser.Close | parser.NoChildren
 	}
 
+	// for case "\[ ... ]" (no close marker on the same line)
+	for i := pos + 2 + idx + 2; i < len(line); i++ {
+		if line[i] != ' ' && line[i] != '\n' {
+			return nil, parser.NoChildren
+		}
+	}
+
 	segment.Start += pos + 2
 	node.Lines().Append(segment)
 	return node, parser.NoChildren
@@ -85,7 +94,7 @@ func (b *blockParser) Continue(node ast.Node, reader text.Reader, pc parser.Cont
 	line, segment := reader.PeekLine()
 	w, pos := util.IndentWidth(line, reader.LineOffset())
 	if w < 4 {
-		endBytes := giteaUtil.Iif(block.Dollars, b.endBytesDollars, b.endBytesBracket)
+		endBytes := giteaUtil.Iif(block.Dollars, b.endBytesDollars, b.endBytesSquare)
 		if bytes.HasPrefix(line[pos:], endBytes) && util.IsBlank(line[pos+len(endBytes):]) {
 			if util.IsBlank(line[pos+len(endBytes):]) {
 				newline := giteaUtil.Iif(line[len(line)-1] != '\n', 0, 1)

modules/markup/markdown/math/inline_node.go

@@ -8,7 +8,7 @@ import (
 	"github.com/yuin/goldmark/util"
 )
 
-// Inline represents inline math e.g. $...$ or \(...\)
+// Inline struct represents inline math e.g. $...$ or \(...\)
 type Inline struct {
 	ast.BaseInline
 }

modules/markup/markdown/math/inline_parser.go

@@ -12,31 +12,25 @@ import (
 )
 
 type inlineParser struct {
-	start []byte
-	end   []byte
+	trigger              []byte
+	endBytesSingleDollar []byte
+	endBytesDoubleDollar []byte
+	endBytesBracket      []byte
 }
 
 var defaultInlineDollarParser = &inlineParser{
-	start: []byte{'$'},
-	end:   []byte{'$'},
-}
-
-var defaultDualDollarParser = &inlineParser{
-	start: []byte{'$', '$'},
-	end:   []byte{'$', '$'},
+	trigger:              []byte{'$'},
+	endBytesSingleDollar: []byte{'$'},
+	endBytesDoubleDollar: []byte{'$', '$'},
 }
 
 func NewInlineDollarParser() parser.InlineParser {
 	return defaultInlineDollarParser
 }
 
-func NewInlineDualDollarParser() parser.InlineParser {
-	return defaultDualDollarParser
-}
-
 var defaultInlineBracketParser = &inlineParser{
-	start: []byte{'\\', '('},
-	end:   []byte{'\\', ')'},
+	trigger:         []byte{'\\', '('},
+	endBytesBracket: []byte{'\\', ')'},
 }
 
 func NewInlineBracketParser() parser.InlineParser {
@@ -45,7 +39,7 @@ func NewInlineBracketParser() parser.InlineParser {
 
 // Trigger triggers this parser on $ or \
 func (parser *inlineParser) Trigger() []byte {
-	return parser.start
+	return parser.trigger
 }
 
 func isPunctuation(b byte) bool {
@@ -64,33 +58,60 @@ func isAlphanumeric(b byte) bool {
 func (parser *inlineParser) Parse(parent ast.Node, block text.Reader, pc parser.Context) ast.Node {
 	line, _ := block.PeekLine()
 
-	if !bytes.HasPrefix(line, parser.start) {
+	if !bytes.HasPrefix(line, parser.trigger) {
 		// We'll catch this one on the next time round
 		return nil
 	}
 
-	precedingCharacter := block.PrecendingCharacter()
-	if precedingCharacter < 256 && (isAlphanumeric(byte(precedingCharacter)) || isPunctuation(byte(precedingCharacter))) {
-		// need to exclude things like `a$` from being considered a start
-		return nil
+	var startMarkLen int
+	var stopMark []byte
+	checkSurrounding := true
+	if line[0] == '$' {
+		startMarkLen = 1
+		stopMark = parser.endBytesSingleDollar
+		if len(line) > 1 {
+			if line[1] == '$' {
+				startMarkLen = 2
+				stopMark = parser.endBytesDoubleDollar
+			} else if line[1] == '`' {
+				pos := 1
+				for ; pos < len(line) && line[pos] == '`'; pos++ {
+				}
+				startMarkLen = pos
+				stopMark = bytes.Repeat([]byte{'`'}, pos)
+				stopMark[len(stopMark)-1] = '$'
+				checkSurrounding = false
+			}
+		}
+	} else {
+		startMarkLen = 2
+		stopMark = parser.endBytesBracket
+	}
+
+	if checkSurrounding {
+		precedingCharacter := block.PrecendingCharacter()
+		if precedingCharacter < 256 && (isAlphanumeric(byte(precedingCharacter)) || isPunctuation(byte(precedingCharacter))) {
+			// need to exclude things like `a$` from being considered a start
+			return nil
+		}
 	}
 
 	// move the opener marker point at the start of the text
-	opener := len(parser.start)
+	opener := startMarkLen
 
 	// Now look for an ending line
 	depth := 0
 	ender := -1
 	for i := opener; i < len(line); i++ {
-		if depth == 0 && bytes.HasPrefix(line[i:], parser.end) {
+		if depth == 0 && bytes.HasPrefix(line[i:], stopMark) {
 			succeedingCharacter := byte(0)
-			if i+len(parser.end) < len(line) {
-				succeedingCharacter = line[i+len(parser.end)]
+			if i+len(stopMark) < len(line) {
+				succeedingCharacter = line[i+len(stopMark)]
 			}
 			// check valid ending character
 			isValidEndingChar := isPunctuation(succeedingCharacter) || isBracket(succeedingCharacter) ||
 				succeedingCharacter == ' ' || succeedingCharacter == '\n' || succeedingCharacter == 0
-			if !isValidEndingChar {
+			if checkSurrounding && !isValidEndingChar {
 				break
 			}
 			ender = i
@@ -112,21 +133,12 @@ func (parser *inlineParser) Parse(parent ast.Node, block text.Reader, pc parser.
 
 	block.Advance(opener)
 	_, pos := block.Position()
-	var node ast.Node
-	if parser == defaultDualDollarParser {
-		node = NewInlineBlock()
-	} else {
-		node = NewInline()
-	}
+	node := NewInline()
+
 	segment := pos.WithStop(pos.Start + ender - opener)
 	node.AppendChild(node, ast.NewRawTextSegment(segment))
-	block.Advance(ender - opener + len(parser.end))
-
-	if parser == defaultDualDollarParser {
-		trimBlock(&(node.(*InlineBlock)).Inline, block)
-	} else {
-		trimBlock(node.(*Inline), block)
-	}
+	block.Advance(ender - opener + len(stopMark))
+	trimBlock(node, block)
 	return node
 }
 

modules/markup/markdown/math/inline_renderer.go

@@ -50,5 +50,4 @@ func (r *InlineRenderer) renderInline(w util.BufWriter, source []byte, n ast.Nod
 // RegisterFuncs registers the renderer for inline math nodes
 func (r *InlineRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
 	reg.Register(KindInline, r.renderInline)
-	reg.Register(KindInlineBlock, r.renderInline)
 }