Generalise and support 8, 256 and 16m colour terminals.

lexers/api.go

@@ -0,0 +1,77 @@
+package lexers
+
+import (
+	"path/filepath"
+	"sort"
+
+	"github.com/danwakefield/fnmatch"
+
+	"github.com/alecthomas/chroma"
+)
+
+type prioritisedLexers []chroma.Lexer
+
+func (p prioritisedLexers) Len() int           { return len(p) }
+func (p prioritisedLexers) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
+func (p prioritisedLexers) Less(i, j int) bool { return p[i].Config().Priority < p[j].Config().Priority }
+
+// Registry of Lexers.
+var Registry = struct {
+	Lexers []chroma.Lexer
+	byName map[string]chroma.Lexer
+}{
+	byName: 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...)
+		}
+	}
+	return out
+}
+
+// Get a Lexer by name.
+func Get(name string) chroma.Lexer {
+	lexer, ok := Registry.byName[name]
+	if ok {
+		return lexer
+	}
+	return Fallback
+}
+
+// Match returns all lexers matching filename.
+func Match(filename string) []chroma.Lexer {
+	filename = filepath.Base(filename)
+	lexers := prioritisedLexers{}
+	for _, lexer := range Registry.Lexers {
+		config := lexer.Config()
+		for _, glob := range config.Filenames {
+			if fnmatch.Match(glob, filename, 0) {
+				lexers = append(lexers, lexer)
+				break
+			}
+		}
+	}
+	sort.Sort(lexers)
+	return lexers
+}
+
+// Register a Lexer with the global registry.
+func Register(lexer chroma.Lexer, err error) chroma.Lexer {
+	if err != nil {
+		panic(err)
+	}
+	config := lexer.Config()
+	Registry.byName[config.Name] = lexer
+	for _, alias := range config.Aliases {
+		Registry.byName[alias] = lexer
+	}
+	Registry.Lexers = append(Registry.Lexers, lexer)
+	return lexer
+}