Handle escapes in string literals.

frog/tests/leg_only/src/StringEscapeTest.dart

Index: frog/tests/leg_only/src/StringEscapeTest.dart
diff --git a/frog/tests/leg_only/src/StringEscapeTest.dart b/frog/tests/leg_only/src/StringEscapeTest.dart
new file mode 100644
index 0000000000000000000000000000000000000000..a95dddfc537b8517da23b097f0b27f244381b6ed
--- /dev/null
+++ b/frog/tests/leg_only/src/StringEscapeTest.dart
@@ -0,0 +1,135 @@
+// Copyright (c) 2011, 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.
+
+// Test that string escapes work correctly.
+
+testSingleCharacterEscapes() {
+  List/*<String>*/ examples = [
+    "\b\f\n\r\t\v",
+    '\b\f\n\r\t\v',
+    """\b\f\n\r\t\v""",
+    '''\b\f\n\r\t\v''',
+  ];
+  List values = [8, 12, 10, 13, 9, 11];
+  for (String s in examples) {
+    Expect.equals(6, s.length);
+    for (int i = 0; i < 6; i++) {
+      Expect.equals(values[i], s.charCodeAt(i));
+    }
+  }
+}
+
+testXEscapes() {
+  var allBytes =
+      "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f" +
+      "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f" +
+      "\x20\x21\x22\x23\x24\x25\x26\x27\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f" +
+      "\x30\x31\x32\x33\x34\x35\x36\x37\x38\x39\x3a\x3b\x3c\x3d\x3e\x3f" +
+      "\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x4a\x4b\x4c\x4d\x4e\x4f" +
+      "\x50\x51\x52\x53\x54\x55\x56\x57\x58\x59\x5a\x5b\x5c\x5d\x5e\x5f" +
+      "\x60\x61\x62\x63\x64\x65\x66\x67\x68\x69\x6a\x6b\x6c\x6d\x6e\x6f" +
+      "\x70\x71\x72\x73\x74\x75\x76\x77\x78\x79\x7a\x7b\x7c\x7d\x7e\x7f" +
+      "\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f" +
+      "\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f" +
+      "\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf" +
+      "\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf" +
+      "\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf" +
+      "\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf" +
+      "\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef" +
+      "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff";
+  Expect.equals(256, allBytes.length);
+  for (int i = 0; i < 256; i++) {
+    Expect.equals(i, allBytes.charCodeAt(i));
+  }
+}
+
+testUEscapes() {
+  List/*String*/ examples =
+    ["\u0000\u0001\u0022\u0027\u005c\u007f\u0080\u00ff" +
+     "\u0100\u1000\ud7ff\ue000\uffff",
+     '\u0000\u0001\u0022\u0027\u005c\u007f\u0080\u00ff' +
+     '\u0100\u1000\ud7ff\ue000\uffff',
+     """\u0000\u0001\u0022\u0027\u005c\u007f\u0080\u00ff""" +
+     """\u0100\u1000\ud7ff\ue000\uffff""",
+     '''\u0000\u0001\u0022\u0027\u005c\u007f\u0080\u00ff''' +
+     '''\u0100\u1000\ud7ff\ue000\uffff'''];
+  List/*<int>*/ values = [0, 1, 0x22, 0x27, 0x5c, 0x7f, 0x80, 0xff,
+                          0x100, 0x1000, 0xd7ff, 0xe000, 0xffff];
+  for (String s in examples) {
+    Expect.equals(values.length, s.length);
+    for (int i = 0; i < values.length; i++) {
+      Expect.equals(values[i], s.charCodeAt(i));
+    }
+  }
+  // No characters above 0xffff, since we don't pass those to JS.
+  var long =
+      "\u{0}\u{00}\u{000}\u{0000}\u{00000}\u{000000}\u{0000000}" +
+      "\u{1}\u{01}\u{001}\u{00001}" +
+      "\u{ffff}\u{0ffff}\u{00ffff}\u{000ffff}";
+  var longValues = [0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1,
+                    0xffff, 0xffff, 0xffff, 0xffff];
+  Expect.equals(longValues.length, long.length);
+  for (int i = 0; i < longValues.length; i++) {
+    Expect.equals(longValues[i], long.charCodeAt(i));
+  }
+
+  // LEG-ONLY behavior. We discard characters outside of the MBR,
+  // and replace them with U+FFFD (Invalid).
+  var nonMBR = "\u{10000}";

[floitsch, 2012/01/12 12:30:28]

I'm not sure this is the correct approach.

[Lasse Reichstein Nielsen, 2012/01/16 13:30:23]

Not in the long run. 
A more correct approach is far more complicated, so this will have to do for now
(we can't just expand to a surrogate pair because we still use the JS String
.length for string length, so we need something that's not a JS string to hold
it).

+  Expect.equals(1, nonMBR.length);
+  Expect.equals(0xfffd, nonMBR.charCodeAt(0));
+}
+
+testIdentityEscapes() {
+  // All non-control ASCII characters escaped, except those with special
+  // meaning: b, f, n, r, t, u, v, and x (replaced by \x00).
+  var asciiLiterals =
+    "\ \!\"\#\$\%\&\'\(\)\*\+\,\-\.\/\0\1\2\3\4\5\6\7\8\9\:\;\<\=\>" +
+    "\?\@\A\B\C\D\E\F\G\H\I\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z\[\\\]" +
+    "\^\_\`\a\x00\c\d\e\x00\g\h\i\j\k\l\m\x00\o\p\q\x00\s\x00\x00\x00" +
+    "\w\x00\y\z\{\|\}\~\";
+
+  Expect.equals(128 - 32, asciiLiterals.length);
+  for (int i = 32; i < 128; i++) {
+    int code = asciiLiterals.charCodeAt(i - 32);
+    if (code != 0) {
+      Expect.equals(i, code);
+    }
+  }
+}
+
+
+testQuotes() {
+  // The string [ "' ].
+  String bothQuotes = ' "' + "' ";
+  Expect.equals(bothQuotes, " \"' ");
+  Expect.equals(bothQuotes, ' "\' ');
+  Expect.equals(bothQuotes, """ "' """);
+  Expect.equals(bothQuotes, ''' "' ''');
+  Expect.equals(bothQuotes, @""" "' """);
+  Expect.equals(bothQuotes, @''' "' ''');
+}
+
+
+testRawStrings() {
+  String raw1 = @'\x00';
+  Expect.equals(4, raw1.length);
+  Expect.equals(0x5c, raw1.charCodeAt(0));
+}
+
+main() {
+  // Test \x??.
+  testXEscapes();
+  // Test \u???? and \u{?+}.
+  testUEscapes();
+  // Test \b, \f, \n, \r, \t, \v.
+  testSingleCharacterEscapes();
+  // Test all other single character (identity) escaeps.
+  testIdentityEscapes();
+  // Test that quotes are handled correctly.
+  testQuotes();
+  // Test that raw strings are raw.
+  testRawStrings();
+}