package internal import ( "path/filepath" "sort" "strings" "github.com/danwakefield/fnmatch" "github.com/alecthomas/chroma" ) // Registry of Lexers. var Registry = struct { Lexers chroma.Lexers byName map[string]chroma.Lexer byAlias map[string]chroma.Lexer }{ byName: map[string]chroma.Lexer{}, byAlias: map[string]chroma.Lexer{}, } // Names of all lexers, optionally including aliases. func Names(withAliases bool) []string { out := []string{} for _, lexer := range Registry.Lexers { config := lexer.Config() out = append(out, config.Name) if withAliases { out = append(out, config.Aliases...) } } sort.Strings(out) return out } // Get a Lexer by name, alias or file extension. func Get(name string) chroma.Lexer { candidates := chroma.PrioritisedLexers{} if lexer := Registry.byName[name]; lexer != nil { candidates = append(candidates, lexer) } if lexer := Registry.byAlias[name]; lexer != nil { candidates = append(candidates, lexer) } if lexer := Registry.byName[strings.ToLower(name)]; lexer != nil { candidates = append(candidates, lexer) } if lexer := Registry.byAlias[strings.ToLower(name)]; lexer != nil { candidates = append(candidates, lexer) } // Try file extension. if lexer := Match("filename." + name); lexer != nil { candidates = append(candidates, lexer) } // Try exact filename. if lexer := Match(name); lexer != nil { candidates = append(candidates, lexer) } if len(candidates) == 0 { return nil } sort.Sort(candidates) return candidates[0] } // MatchMimeType attempts to find a lexer for the given MIME type. func MatchMimeType(mimeType string) chroma.Lexer { matched := chroma.PrioritisedLexers{} for _, l := range Registry.Lexers { for _, lmt := range l.Config().MimeTypes { if mimeType == lmt { matched = append(matched, l) } } } if len(matched) != 0 { sort.Sort(matched) return matched[0] } return nil } // Match returns the first lexer matching filename. func Match(filename string) chroma.Lexer { filename = filepath.Base(filename) matched := chroma.PrioritisedLexers{} // First, try primary filename matches. for _, lexer := range Registry.Lexers { config := lexer.Config() for _, glob := range config.Filenames { if fnmatch.Match(glob, filename, 0) { matched = append(matched, lexer) } } } if len(matched) > 0 { sort.Sort(matched) return matched[0] } matched = nil // Next, try filename aliases. for _, lexer := range Registry.Lexers { config := lexer.Config() for _, glob := range config.AliasFilenames { if fnmatch.Match(glob, filename, 0) { matched = append(matched, lexer) } } } if len(matched) > 0 { sort.Sort(matched) return matched[0] } return nil } // Analyse text content and return the "best" lexer.. func Analyse(text string) chroma.Lexer { var picked chroma.Lexer highest := float32(0.0) for _, lexer := range Registry.Lexers { if analyser, ok := lexer.(chroma.Analyser); ok { weight := analyser.AnalyseText(text) if weight > highest { picked = lexer highest = weight } } } return picked } // Register a Lexer with the global registry. func Register(lexer chroma.Lexer) chroma.Lexer { config := lexer.Config() Registry.byName[config.Name] = lexer Registry.byName[strings.ToLower(config.Name)] = lexer for _, alias := range config.Aliases { Registry.byAlias[alias] = lexer Registry.byAlias[strings.ToLower(alias)] = lexer } Registry.Lexers = append(Registry.Lexers, lexer) return lexer } // Fallback lexer if no other is found. var Fallback chroma.Lexer = chroma.MustNewLexer(&chroma.Config{ Name: "fallback", Filenames: []string{"*"}, }, chroma.Rules{ "root": []chroma.Rule{ {`.+`, chroma.Text, nil}, {`\n`, chroma.Text, nil}, }, })