| part of petitparser; |
| |
| /// A token represents a parsed part of the input stream. |
| /// |
| /// The token holds the resulting value of the input, the input buffer, |
| /// and the start and stop position in the input buffer. It provides many |
| /// convenience methods to access the state of the token. |
| class Token { |
| |
| /// The parsed value of the token. |
| final value; |
| |
| /// The parsed buffer of the token. |
| final buffer; |
| |
| /// The start position of the token in the buffer. |
| final int start; |
| |
| /// The stop position of the token in the buffer. |
| final int stop; |
| |
| /// Constructs a token from the parsed value, the input buffer, and the |
| /// start and stop position in the input buffer. |
| const Token(this.value, this.buffer, this.start, this.stop); |
| |
| /// The consumed input of the token. |
| get input => buffer is String |
| ? buffer.substring(start, stop) |
| : buffer.sublist(start, stop); |
| |
| /// The length of the token. |
| int get length => stop - start; |
| |
| /// The line number of the token (only works for [String] buffers). |
| int get line => Token.lineAndColumnOf(buffer, start)[0]; |
| |
| /// The column number of this token (only works for [String] buffers). |
| int get column => Token.lineAndColumnOf(buffer, start)[1]; |
| |
| @override |
| String toString() => 'Token[${positionString(buffer, start)}]: $value'; |
| |
| @override |
| bool operator ==(other) { |
| return other is Token |
| && value == other.value |
| && start == other.start |
| && stop == other.stop; |
| } |
| |
| @override |
| int get hashCode => value.hashCode + start.hashCode + stop.hashCode; |
| |
| /// Returns a parser for that detects newlines platform independently. |
| static Parser newlineParser() => _newlineParser; |
| |
| static final Parser _newlineParser = char('\n') | (char('\r') & char('\n').optional()); |
| |
| /// Converts the [position] index in a [buffer] to a line and column tuple. |
| static List<int> lineAndColumnOf(String buffer, int position) { |
| var line = 1, offset = 0; |
| for (var token in newlineParser().token().matchesSkipping(buffer)) { |
| if (position < token.stop) { |
| return [line, position - offset + 1]; |
| } |
| line++; |
| offset = token.stop; |
| } |
| return [line, position - offset + 1]; |
| } |
| |
| /// Returns a human readable string representing the [position] index in a [buffer]. |
| static String positionString(buffer, int position) { |
| if (buffer is String) { |
| var lineAndColumn = Token.lineAndColumnOf(buffer, position); |
| return '${lineAndColumn[0]}:${lineAndColumn[1]}'; |
| } else { |
| return '$position'; |
| } |
| } |
| } |