compileParseTreePattern method

ParseTreePattern compileParseTreePattern(String pattern, int patternRuleIndex, [ Lexer? lexer ])

The preferred method of getting a tree pattern. For example, here's a sample use:

ParseTree t = parser.expr();
ParseTreePattern p = parser.compileParseTreePattern("<ID>+0", MyParser.RULE_expr);
ParseTreeMatch m = p.match(t);
String id = m.get("ID");

Implementation

ParseTreePattern compileParseTreePattern(
  String pattern,
  int patternRuleIndex, [
  Lexer? lexer,
]) {
  if (lexer == null) {
    final tokenSource = tokenStream.tokenSource;
    if (tokenSource is! Lexer) {
      throw UnsupportedError("Parser can't discover a lexer to use");
    }
    lexer = tokenSource;
  }

  final m = ParseTreePatternMatcher(lexer, this);
  return m.compile(pattern, patternRuleIndex);
}