Add markdown and syntax-highlight presenter
DDavid committed on 2026-06-28 01:20 commit 23bef50
internal/interface/web/presenter/render.go +50 −0
+package presenter
+
+import (
+ "bytes"
+
+ chromahtml "github.com/alecthomas/chroma/v2/formatters/html"
+ "github.com/alecthomas/chroma/v2/lexers"
+ "github.com/alecthomas/chroma/v2/styles"
+ "github.com/yuin/goldmark"
+ "github.com/yuin/goldmark/extension"
+)
+
+var md = goldmark.New(goldmark.WithExtensions(extension.GFM))
+
+// RenderMarkdown converts markdown to HTML. Raw HTML in the source is escaped
+// (goldmark's default, no WithUnsafe), which keeps user content safe.
+func RenderMarkdown(src []byte) string {
+ var buf bytes.Buffer
+ if err := md.Convert(src, &buf); err != nil {
+ return "<pre>" + string(src) + "</pre>"
+ }
+ return buf.String()
+}
+
+var (
+ highlightStyle = styles.Get("github")
+ highlightFormatter = chromahtml.New(chromahtml.WithClasses(false), chromahtml.WithLineNumbers(true))
+)
+
+// Highlight renders source code as highlighted HTML, choosing a lexer by filename.
+func Highlight(code, filename string) string {
+ lexer := lexers.Match(filename)
+ if lexer == nil {
+ lexer = lexers.Analyse(code)
+ }
+ if lexer == nil {
+ lexer = lexers.Fallback
+ }
+
+ iterator, err := lexer.Tokenise(nil, code)
+ if err != nil {
+ return "<pre>" + code + "</pre>"
+ }
+
+ var buf bytes.Buffer
+ if err := highlightFormatter.Format(&buf, highlightStyle, iterator); err != nil {
+ return "<pre>" + code + "</pre>"
+ }
+ return buf.String()
+}