Added example/example.dart, update README to working, valid code
Fixes https://github.com/dart-lang/string_scanner/issues/9
diff --git a/pkgs/string_scanner/README.md b/pkgs/string_scanner/README.md
index 90660fc..15aa242 100644
--- a/pkgs/string_scanner/README.md
+++ b/pkgs/string_scanner/README.md
@@ -8,7 +8,7 @@
num parseNumber(String source) {
// Scan a number ("1", "1.5", "-3").
- var scanner = new StringScanner(source);
+ var 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.
@@ -16,14 +16,14 @@
// [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.expect(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]);
+ var number = num.parse(scanner.lastMatch[0]);
if (scanner.scan(".")) {
- scanner.expect(new RegExp(r"\d+"));
+ scanner.expect(RegExp(r"\d+"));
var decimal = scanner.lastMatch[0];
number += int.parse(decimal) / math.pow(10, decimal.length);
}
diff --git a/pkgs/string_scanner/example/example.dart b/pkgs/string_scanner/example/example.dart
new file mode 100644
index 0000000..ddd9d3e
--- /dev/null
+++ b/pkgs/string_scanner/example/example.dart
@@ -0,0 +1,40 @@
+// Copyright (c) 2019, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:math' as math;
+
+import 'package:string_scanner/string_scanner.dart';
+
+void main(List<String> args) {
+ print(parseNumber(args.single));
+}
+
+num parseNumber(String source) {
+ // Scan a number ("1", "1.5", "-3").
+ var 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.
+ 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(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+"));
+ 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;
+}
