可運行首版 (#2)

	標準以及常用的code-block顏色可以渲染(Monokai樣式)

README.md

@@ -5,3 +5,7 @@
 ## 參考資料
 
 - [github.com/yuin/goldmark-highlighting](https://github.com/yuin/goldmark-highlighting)
+- [github.com/alecthomas/chroma](https://github.com/alecthomas/chroma) 掌管主題顏色的細節，例如{背景、數字、註解、字串...}[等相關屬性](https://github.com/alecthomas/chroma/blob/6138519d55582350e5dec0147cb8f5ddcb78f8cf/styles/swapoff.go#L8-L25)
+  - Style
+    - [Chroma Style Gallery](https://xyproto.github.io/splash/docs/)
+    - [Source](https://github.com/alecthomas/chroma/tree/3f86ac7/styles): 這邊每一個檔案都表示一種style

v2/chroma.go

@@ -0,0 +1,8 @@
+package highlighting
+
+import "github.com/alecthomas/chroma/v2/styles"
+
+// DefaultStyle
+// https://xyproto.github.io/splash/docs/
+// https://github.com/alecthomas/chroma/tree/3f86ac7/styles
+var DefaultStyle = styles.Monokai

v2/go.mod

@@ -2,4 +2,9 @@ module github.com/CarsonSlovoka/goldmark-highlighting/v2
 
 go 1.19
 
-require github.com/yuin/goldmark v1.4.14
+require (
+	github.com/alecthomas/chroma/v2 v2.3.0
+	github.com/yuin/goldmark v1.4.14
+)
+
+require github.com/dlclark/regexp2 v1.4.0 // indirect

v2/go.sum

@@ -0,0 +1,11 @@
+github.com/alecthomas/chroma/v2 v2.3.0 h1:83xfxrnjv8eK+Cf8qZDzNo3PPF9IbTWHs7z28GY6D0U=
+github.com/alecthomas/chroma/v2 v2.3.0/go.mod h1:mZxeWZlxP2Dy+/8cBob2PYd8O2DwNAzave5AY7A2eQw=
+github.com/alecthomas/repr v0.1.0 h1:ENn2e1+J3k09gyj2shc0dHr/yjaWSHRlrJ4DPMevDqE=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/dlclark/regexp2 v1.4.0 h1:F1rxgk7p4uKjwIQxBs9oAXe5CqrXlCduYEJvrF4u93E=
+github.com/dlclark/regexp2 v1.4.0/go.mod h1:2pZnwuY/m+8K6iRw6wQdMtk+rH5tNGR1i55kozfMjCc=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/stretchr/testify v1.8.0 h1:pSgiaMZlXftHpm5L7V1+rVB+AZJydKsMxsQBIJw4PKk=
+github.com/yuin/goldmark v1.4.14 h1:jwww1XQfhJN7Zm+/a1ZA/3WUiEBEroYFNTiV3dKwM8U=
+github.com/yuin/goldmark v1.4.14/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

v2/renderer.go

@@ -1,6 +1,11 @@
 package highlighting
 
 import (
+	"bytes"
+	"fmt"
+	"github.com/alecthomas/chroma/v2"
+	chromahtml "github.com/alecthomas/chroma/v2/formatters/html"
+	"github.com/alecthomas/chroma/v2/lexers"
 	"github.com/yuin/goldmark/ast"
 	"github.com/yuin/goldmark/renderer"
 	"github.com/yuin/goldmark/util"
@@ -13,10 +18,101 @@ func NewHighlightingHTMLRenderer() renderer.NodeRenderer {
 }
 
 func (r *highlightingHTMLRenderer) RegisterFuncs(reg renderer.NodeRendererFuncRegisterer) {
-	reg.Register(ast.KindFencedCodeBlock, r.nodeRendererFunc) // codeblock不需要再定義額外的ast去描述，基於原始的KindFencedCodeBlock增加額外的判斷即可
+	reg.Register(ast.KindFencedCodeBlock, r.nodeRendererFunc) // codeBlock不需要再定義額外的ast去描述，基於原始的KindFencedCodeBlock增加額外的判斷即可
 }
 
 // nodeRendererFunc 此函數可以把結果直接寫到writer之中，就能對輸出產生影響
-func (r *highlightingHTMLRenderer) nodeRendererFunc(writer util.BufWriter, source []byte, n ast.Node, entering bool) (ast.WalkStatus, error) {
-	return 0, nil
+func (r *highlightingHTMLRenderer) nodeRendererFunc(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
+	if !entering {
+		return ast.WalkContinue, nil
+	}
+
+	n := node.(*ast.FencedCodeBlock) // 轉成對應的ast.Node
+
+	// Attributes, // parse ```go{hl_lines=["2-3",5], linenostart=5}
+	{
+		// TODO
+	}
+
+	noHighlight := false
+	guessLanguage := false
+
+	var codeBlockContent bytes.Buffer
+	l := n.Lines().Len()
+	for i := 0; i < l; i++ { // 把code-block的內容，一列一列的寫進去
+		line := n.Lines().At(i)
+		codeBlockContent.Write(line.Value(source)) // source是一個比較大的項目，可以包含code-block以外的內容
+	}
+
+	language := n.Language(source) // 當前code-block所用的語言 ```myLang
+
+	// 定義預設的code-block函數
+	defaultCodeBlockHandlerFunc := func() (ast.WalkStatus, error) {
+		// Header
+		{
+			if language != nil {
+				_, _ = w.WriteString(fmt.Sprintf("<pre>\n<code class=\"language-%s\">", language))
+			} else {
+				_, _ = w.WriteString("<pre>\n<code>")
+			}
+		}
+		// Body
+		{
+			_, _ = w.WriteString(codeBlockContent.String())
+		}
+		// Tail
+		{
+			_, _ = w.WriteString("</code>\n</pre>\n")
+		}
+		return ast.WalkContinue, nil
+	}
+
+	var lexer chroma.Lexer
+	if language != nil {
+		lexer = lexers.Get(string(language))
+		if lexer != nil {
+			return r.writeCodeBlock(
+				w, lexer, &codeBlockContent,
+				defaultCodeBlockHandlerFunc, // 如果錯誤就用預設的code-block取代
+			)
+		}
+	}
+
+	if !noHighlight && guessLanguage {
+		if lexer = lexers.Analyse(codeBlockContent.String()); lexer != nil {
+			return r.writeCodeBlock(w, lexer, &codeBlockContent, defaultCodeBlockHandlerFunc)
+		}
+	}
+
+	return defaultCodeBlockHandlerFunc()
+}
+
+func (r *highlightingHTMLRenderer) writeCodeBlock(
+	w util.BufWriter, lexer chroma.Lexer, codeBlockContent *bytes.Buffer,
+	defaultHandlerFunc func() (ast.WalkStatus, error),
+) (ast.WalkStatus, error) {
+
+	if lexer == nil {
+		return ast.WalkContinue, nil
+	}
+	language := []byte(lexer.Config().Name)
+	lexer = chroma.Coalesce(lexer) // 常態化lexer。所得到的結果還是一個Laxer型別
+
+	iterator, err := lexer.Tokenise(nil, codeBlockContent.String()) // 這裡開始準備解析code-block的文本，他會把所有文本解析出個別的關鍵字，整理出一份token清單，可以被疊代
+	if err != nil {
+		return defaultHandlerFunc()
+	}
+
+	formatter := chromahtml.New()
+
+	// Head
+	_, _ = w.WriteString(fmt.Sprintf("<div class=\"highlight %s\">\n", language))
+
+	// Body
+	_ = formatter.Format(w, DefaultStyle, iterator) // chroma的核心，可以把該token渲染成指定的樣式
+
+	// Tail
+	_, _ = w.WriteString("\n</div>")
+
+	return ast.WalkContinue, nil
 }