remove duplicate characters inside []

ilius · Jan 4, 2020 · f600534 · f600534
1 parent 4c252f4
commit f600534
Showing 1 changed file with 16 additions and 1 deletion.
diff --git a/lex_charclass.go b/lex_charclass.go
@@ -47,6 +47,19 @@ func (g *charsetGroupGenerator) Entropy() (float64, error) {
 	return entropy, nil
 }
 
+func removeDuplicateRunes(list []rune) []rune {
+	set := map[rune]bool{}
+	newlist := make([]rune, 0, len(list))
+	for _, c := range list {
+		if set[c] {
+			continue
+		}
+		set[c] = true
+		newlist = append(newlist, c)
+	}
+	return newlist
+}
+
 func lexRange(s *State) (LexType, error) {
 	if s.end() {
 		return nil, s.errorSyntax("'[' not closed")
@@ -68,8 +81,10 @@ func lexRange(s *State) (LexType, error) {
 	case '-':
 		return lexRangeDash, nil
 	case ']':
+		charset := s.patternBuff
+		charset = removeDuplicateRunes(charset)
 		s.lastGen = &charsetGroupGenerator{
-			charsets: [][]rune{s.patternBuff},
+			charsets: [][]rune{charset},
 		}
 		err := s.lastGen.Generate(s)
 		if err != nil {