| commit | 1719b933f1e46b302f0170df205144831f35958d | [log] [tgz] |
|---|---|---|
| author | Nate Bosch <nbosch@google.com> | Fri Jan 29 14:47:54 2021 -0800 |
| committer | GitHub <noreply@github.com> | Fri Jan 29 14:47:54 2021 -0800 |
| tree | 26ed0a8a492e6a9f8dac7a6ea58c00d99b976e83 | |
| parent | 8bd12d511c1eb826f23c2736c1ea4927ffef1a64 [diff] |
Revert "Remove dependency on package:charcode (#29)" (#33) This reverts commit 7e41395d327e93b432f380aaf4c9668f0d952ef3. Since this has not been published or rolled through to the SDK or Flutter we will hold it back to reduce risk.
This package exposes a StringScanner type that makes it easy to parse a string using a series of Patterns. For example:
import 'dart:math' as math; import 'package:string_scanner/string_scanner.dart'; num parseNumber(String source) { // Scan a number ("1", "1.5", "-3"). final scanner = 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. final 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(RegExp(r'\d+')); // [Scanner.lastMatch] holds the [MatchData] for the most recent call to // [Scanner.scan], [Scanner.expect], or [Scanner.matches]. var number = num.parse(scanner.lastMatch[0]); if (scanner.scan('.')) { scanner.expect(RegExp(r'\d+')); final 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; }