commit | edf541b1787796679ec5520dc4259b082634737d | [log] [tgz] |
---|---|---|
author | nweiz@google.com <nweiz@google.com> | Fri May 30 00:52:40 2014 +0000 |
committer | nweiz@google.com <nweiz@google.com> | Fri May 30 00:52:40 2014 +0000 |
tree | 34e1e811cd62a905a1c036b941c72217316faf5e | |
parent | d76b3f384bdd1688eaac5bba36b38fcd1b3724a8 [diff] |
Add LineScanner and SpanScanner classes to string_scanner. R=rnystrom@google.com Review URL: https://codereview.chromium.org//299973002 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart/pkg/string_scanner@36815 260f80e4-7a28-3924-810f-c04153c831b5
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; }