Clone this repo:
  1. 705e7bb Enable and fix a number of lints, test on oldest supported SDK (#15) by Kevin Moore · 3 weeks ago master
  2. 4c6d722 Fix changelog for release (#13) by Kevin Moore · 9 months ago 1.0.4
  3. bf30d63 Update .gitignore to new `dart_tool` pub cache (#8) by BC Ko · 9 months ago
  4. 97cdbe2 Annotate method error with alwaysThrows annotation. (#11) by Keerti Parthasarathy · 10 months ago
  5. 9166ca0 chore: set max SDK version to <3.0.0 (#10) by Patrice Chalin · 10 months ago 1.0.3

This package exposes a StringScanner type that makes it easy to parse a string using a series of Patterns. For example:

import 'dart:math';

import 'package:string_scanner/string_scanner.dart';

num parseNumber(String source) {
  // Scan a number ("1", "1.5", "-3").
  var scanner = new StringScanner(source);

  // [Scanner.scan] tries to consume a [Pattern] and returns whether or not it
  // succeeded. It will move the scan pointer past the end of the pattern.
  var negative = scanner.scan("-");

  // [Scanner.expect] consumes a [Pattern] and throws a [FormatError] if it
  // fails. Like [Scanner.scan], it will move the scan pointer forward.
  scanner.expect(new RegExp(r"\d+"));

  // [Scanner.lastMatch] holds the [MatchData] for the most recent call to
  // [Scanner.scan], [Scanner.expect], or [Scanner.matches].
  var number = int.parse(scanner.lastMatch[0]);

  if (scanner.scan(".")) {
    scanner.expect(new RegExp(r"\d+"));
    var decimal = scanner.lastMatch[0];
    number += int.parse(decimal) / math.pow(10, decimal.length);

  // [Scanner.expectDone] will throw a [FormatError] if there's any input that
  // hasn't yet been consumed.

  return (negative ? -1 : 1) * number;