| 1 | package godoc |
| 2 | |
| 3 | import ( |
| 4 | "go/scanner" |
| 5 | "go/token" |
| 6 | "html" |
| 7 | "strings" |
| 8 | ) |
| 9 | |
| 10 | // HighlightDecl returns syntax-highlighted HTML for a Go declaration snippet. |
| 11 | // Unlike HighlightGo, this produces inline HTML without table/line-number wrapping. |
| 12 | func HighlightDecl(src string) string { |
| 13 | // Wrap in a minimal package context so the scanner accepts it. |
| 14 | prefix := "package p\n" |
| 15 | full := []byte(prefix + src) |
| 16 | |
| 17 | fset := token.NewFileSet() |
| 18 | file := fset.AddFile("", fset.Base(), len(full)) |
| 19 | |
| 20 | var s scanner.Scanner |
| 21 | s.Init(file, full, nil, scanner.ScanComments) |
| 22 | |
| 23 | type span struct { |
| 24 | offset int |
| 25 | end int |
| 26 | class string |
| 27 | } |
| 28 | var spans []span |
| 29 | |
| 30 | for { |
| 31 | pos, tok, lit := s.Scan() |
| 32 | if tok == token.EOF { |
| 33 | break |
| 34 | } |
| 35 | |
| 36 | offset := int(pos) - file.Base() |
| 37 | if offset < len(prefix) { |
| 38 | continue // skip the synthetic "package p\n" |
| 39 | } |
| 40 | |
| 41 | var class string |
| 42 | var length int |
| 43 | |
| 44 | switch { |
| 45 | case tok == token.COMMENT: |
| 46 | class = "com" |
| 47 | length = len(lit) |
| 48 | case tok == token.STRING || tok == token.CHAR: |
| 49 | class = "str" |
| 50 | length = len(lit) |
| 51 | case tok == token.INT || tok == token.FLOAT || tok == token.IMAG: |
| 52 | class = "num" |
| 53 | length = len(lit) |
| 54 | case tok.IsKeyword(): |
| 55 | class = "kw" |
| 56 | length = len(tok.String()) |
| 57 | case tok == token.IDENT: |
| 58 | if isBuiltin(lit) { |
| 59 | class = "bi" |
| 60 | length = len(lit) |
| 61 | } |
| 62 | } |
| 63 | |
| 64 | if class != "" { |
| 65 | spans = append(spans, span{ |
| 66 | offset: offset - len(prefix), // adjust to src-relative |
| 67 | end: offset - len(prefix) + length, |
| 68 | class: class, |
| 69 | }) |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | var b strings.Builder |
| 74 | pos := 0 |
| 75 | for _, sp := range spans { |
| 76 | if sp.offset < 0 { |
| 77 | continue |
| 78 | } |
| 79 | start := sp.offset |
| 80 | end := sp.end |
| 81 | if end > len(src) { |
| 82 | end = len(src) |
| 83 | } |
| 84 | if start > pos { |
| 85 | b.WriteString(html.EscapeString(src[pos:start])) |
| 86 | } |
| 87 | b.WriteString(`<span class="`) |
| 88 | b.WriteString(sp.class) |
| 89 | b.WriteString(`">`) |
| 90 | b.WriteString(html.EscapeString(src[start:end])) |
| 91 | b.WriteString(`</span>`) |
| 92 | pos = end |
| 93 | } |
| 94 | if pos < len(src) { |
| 95 | b.WriteString(html.EscapeString(src[pos:])) |
| 96 | } |
| 97 | |
| 98 | return b.String() |
| 99 | } |
| 100 | |