Add string.trimLeft/trimRight.

tests/corelib/string_trimlr_test.dart

+// Copyright (c) 2013, 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 "package:expect/expect.dart";
+
+// Characters with Whitespace property (Unicode 6.2).
+// 0009..000D    ; White_Space # Cc       <control-0009>..<control-000D>
+// 0020          ; White_Space # Zs       SPACE
+// 0085          ; White_Space # Cc       <control-0085>
+// 00A0          ; White_Space # Zs       NO-BREAK SPACE
+// 1680          ; White_Space # Zs       OGHAM SPACE MARK
+// 180E          ; White_Space # Zs       MONGOLIAN VOWEL SEPARATOR
+// 2000..200A    ; White_Space # Zs       EN QUAD..HAIR SPACE
+// 2028          ; White_Space # Zl       LINE SEPARATOR
+// 2029          ; White_Space # Zp       PARAGRAPH SEPARATOR
+// 202F          ; White_Space # Zs       NARROW NO-BREAK SPACE
+// 205F          ; White_Space # Zs       MEDIUM MATHEMATICAL SPACE
+// 3000          ; White_Space # Zs       IDEOGRAPHIC SPACE
+// And BOM:
+// FEFF          ; Byte order mark.
+const WHITESPACE = const [
+  0x09,
+  0x0A,
+  0x0B,
+  0x0C,
+  0x0D,
+  0x20,
+  0x85,
+  0xA0,
+  0x1680,
+  0x180E,
+  0x2000,
+  0x2001,
+  0x2002,
+  0x2003,
+  0x2004,
+  0x2005,
+  0x2006,
+  0x2007,
+  0x2008,
+  0x2009,
+  0x200A,
+  0x2028,
+  0x2029,
+  0x202F,
+  0x205F,
+  0x3000,
+  0xFEFF,
+];
+
+main() {
+  // Test the whitespace in different positions.
+  test(ws) {
+    // trimLeft
+    Expect.equals("", ws.trimLeft(), "K1");
+    Expect.equals("", (ws + ws).trimLeft(), "L2");
+    Expect.equals("a" + ws, ("a" + ws).trimLeft(), "L3");
+    Expect.equals("a", (ws + "a").trimLeft(), "L4");
+    Expect.equals("a" + ws + ws, (ws + ws + "a" + ws + ws).trimLeft(), "L5");
+    Expect.equals("a" + ws + "a", (ws + ws + "a" + ws + "a").trimLeft(), "L6");
+    var untrimmable = "a" + ws + "a";
+    Expect.identical(untrimmable, untrimmable.trimLeft(), "L7");
+    // trimRight
+    Expect.equals("", ws.trimRight(), "R1");
+    Expect.equals("", (ws + ws).trimRight(), "R2");
+    Expect.equals("a", ("a" + ws).trimRight(), "R3");
+    Expect.equals(ws + "a", (ws + "a").trimRight(), "R4");
+    Expect.equals(ws + ws + "a", (ws + ws + "a" + ws + ws).trimRight(), "R5");
+    Expect.equals("a" + ws + "a", ("a" + ws + "a" + ws + ws).trimRight(), "R6");
+    Expect.identical(untrimmable, untrimmable.trimRight(), "R7");
+  }
+
+  // Test each whitespace at different locations.
+  for (var ws in WHITESPACE) {
+    var c = new String.fromCharCode(ws);
+    test(c);
+  }
+  // Test all whitespaces at once at different locations.
+  test(new String.fromCharCodes(WHITESPACE));
+
+  // Empty strings.
+  Expect.identical("", "".trimLeft());
+  Expect.identical("", "".trimRight());
+
+  // Test all BMP chars and one surrogate pair.
+  for (int i = 0, j = 0; i <= 0x10000; i++) {
+    if (j < WHITESPACE.length && i == WHITESPACE[j]) {
+      j++;
+      continue;
+    }
+    // U+200b is currently being treated as whitespace by some JS engines.
+    // Should be fixed in tip-of-tree V8 per 2014-02-10.
+    // This line makes string_trimlr_test/none fail but /01 succeede where
+    // this bug is in the JS. Both succeede on the VM and where the bug is
+    // not. Remove this line and comment if all JS engines fix it.
+    if (i == 0x200b) continue;              /// 01: ok
+
+    var s = new String.fromCharCode(i);
+    Expect.identical(s, s.trimLeft());
+    Expect.identical(s, s.trimRight());
+  }
+}