fix if the lua token is the name of the upstream

Author: xynicole

lex.go

@@ -103,11 +103,15 @@ func tokenize(reader io.Reader, tokenCh chan NgxToken, options LexOptions) {
 	depth := 0
 	var la, quote string
 
+	// check the lua token is not the directive start
+	processdLine := make(map[int]bool)
+
 	scanner := bufio.NewScanner(reader)
 	scanner.Split(bufio.ScanRunes)
 
 	emit := func(line int, quoted bool, err error) {
 		tokenCh <- NgxToken{Value: token.String(), Line: line, IsQuoted: quoted, Error: err}
+		processdLine[line] = true
 		token.Reset()
 		lexState = skipSpace
 	}
@@ -158,7 +162,7 @@ func tokenize(reader io.Reader, tokenCh chan NgxToken, options LexOptions) {
 
 		if token.Len() > 0 {
 			tokenStr := token.String()
-			if ext, ok := externalLexers[tokenStr]; ok {
+			if ext, ok := externalLexers[tokenStr]; ok && !processdLine[tokenLine] {
 				emit(tokenStartLine, false, nil)
 				externalScanner.tokenLine = tokenLine
 				extTokenCh := ext.Lex(tokenStr)