commit | 27d20a3ed710eafbbe26d5c694e583e703ad5916 | [log] [tgz] |
---|---|---|
author | Natalie Weizenbaum <nweiz@google.com> | Tue Sep 01 17:11:08 2015 -0700 |
committer | Natalie Weizenbaum <nweiz@google.com> | Tue Sep 01 17:11:08 2015 -0700 |
tree | fc76b3e0ec8f392e4da3adeeedfd9cb75b177487 | |
parent | a7f8bf873f1f59725c328984b9418c8cf7939890 [diff] |
Properly handle CR LF in LineScanner. R=rnystrom@google.com Review URL: https://codereview.chromium.org//1327713003 .
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; }