commit | 005fab6a6bc2a64ad96aa4b3d19a5ca9d7725efa | [log] [tgz] |
---|---|---|
author | Natalie Weizenbaum <nweiz@google.com> | Mon May 22 12:50:06 2017 -0700 |
committer | GitHub <noreply@github.com> | Mon May 22 12:50:06 2017 -0700 |
tree | 31737aaa568fb7a5d08da4e26c51f7db2e7981a6 | |
parent | 50d0424b331cb7dca4cc30a99ad975a505148d0e [diff] |
Don't crash on surrogate pairs. (#5) Closes #4
This package exposes a StringScanner
type that makes it easy to parse a string using a series of Pattern
s. 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. scanner.expectDone(); return (negative ? -1 : 1) * number; }