[json & uri] cleanup === and !==

lib/json/json.dart

 // Copyright (c) 2012, 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.
 
 #library("dart:json");
 
 #import('dart:math');
 
 // JSON parsing and serialization.
 
@@ skipping 154 matching lines @@
   final int length;
   int position = 0;
 
   static parse(String json) {
     return new _JsonParser(json).parseToplevel();
   }
 
   _JsonParser(String json)
       : json = json,
         length = json.length {
-    if (tokens !== null) return;
+    if (tokens != null) return;
 
     // Use a list as jump-table. It is faster than switch and if.
     tokens = new List<int>(LAST_ASCII + 1);
     tokens[TAB] = WHITESPACE;
     tokens[NEW_LINE] = WHITESPACE;
     tokens[CARRIAGE_RETURN] = WHITESPACE;
     tokens[SPACE] = WHITESPACE;
     tokens[CHAR_0] = NUMBER_LITERAL;
     tokens[CHAR_1] = NUMBER_LITERAL;
     tokens[CHAR_2] = NUMBER_LITERAL;
@@ skipping 12 matching lines @@
     tokens[QUOTE] = STRING_LITERAL;
     tokens[COLON] = COLON;
     tokens[COMMA] = COMMA;
     tokens[CHAR_N] = NULL_LITERAL;
     tokens[CHAR_T] = TRUE_LITERAL;
     tokens[CHAR_F] = FALSE_LITERAL;
   }
 
   parseToplevel() {
     final result = parseValue();
-    if (token() !== null) {
+    if (token() != null) {
       error('Junk at the end of JSON input');
     }
     return result;
   }
 
   parseValue() {
     final int token = token();
-    if (token === null) {
+    if (token == null) {
       error('Nothing to parse');
     }
     switch (token) {
       case STRING_LITERAL: return parseString();
       case NUMBER_LITERAL: return parseNumber();
       case NULL_LITERAL: return expectKeyword(NULL_STRING, null);
       case FALSE_LITERAL: return expectKeyword(FALSE_STRING, false);
       case TRUE_LITERAL: return expectKeyword(TRUE_STRING, true);
       case LBRACE: return parseObject();
       case LBRACKET: return parseList();
@@ skipping 119 matching lines @@
     }
 
     return new String.fromCharCodes(charCodes);
   }
 
   num parseNumber() {
     if (!isToken(NUMBER_LITERAL)) error('Expected number literal');
 
     final int startPos = position;
     int char = char();
-    if (char === MINUS) char = nextChar();
-    if (char === CHAR_0) {
+    if (identical(char, MINUS)) char = nextChar();
+    if (identical(char, CHAR_0)) {
       char = nextChar();
     } else if (isDigit(char)) {
       char = nextChar();
       while (isDigit(char)) char = nextChar();
     } else {
       error('Expected digit when parsing number');
     }
 
     bool isInt = true;
-    if (char === DOT) {
+    if (identical(char, DOT)) {
       char = nextChar();
       if (isDigit(char)) {
         char = nextChar();
         isInt = false;
         while (isDigit(char)) char = nextChar();
       } else {
         error('Expected digit following comma');
       }
     }
 
-    if (char === CHAR_E || char === CHAR_CAPITAL_E) {
+    if (identical(char, CHAR_E) || identical(char, CHAR_CAPITAL_E)) {
       char = nextChar();
-      if (char === MINUS || char === PLUS) char = nextChar();
+      if (identical(char, MINUS) || identical(char, PLUS)) char = nextChar();
       if (isDigit(char)) {
         char = nextChar();
         isInt = false;
         while (isDigit(char)) char = nextChar();
       } else {
         error('Expected digit following \'e\' or \'E\'');
       }
     }
 
     String number = json.substring(startPos, position);
@@ skipping 26 matching lines @@
     position++;
     if (position >= length) return 0;
     return json.charCodeAt(position);
   }
 
   int token() {
     while (true) {
       if (position >= length) return null;
       int char = json.charCodeAt(position);
       int token = tokens[char];
-      if (token === WHITESPACE) {
+      if (identical(token, WHITESPACE)) {
         position++;
         continue;
       }
-      if (token === null) return 0;
+      if (token == null) return 0;
       return token;
     }
   }
 
   void error(String message) {
     throw message;
   }
 }
 
 class _JsonStringifier {
@@ skipping 62 matching lines @@
       } else {
         charCodes.add(charCode);
       }
     }
     sb.add(needsEscape ? new String.fromCharCodes(charCodes) : s);
   }
 
   void checkCycle(final object) {
     // TODO: use Iterables.
     for (int i = 0; i < seen.length; i++) {
-      if (seen[i] === object) {
+      if (identical(seen[i], object)) {
         throw 'Cyclic structure';
       }
     }
     seen.add(object);
   }
 
   void stringifyValue(final object) {
     // Tries stringifying object directly. If it's not a simple value, List or
     // Map, call toJson() to get a custom representation and try serializing
     // that.
@@ skipping 15 matching lines @@
    * Serializes a [num], [String], [bool], [Null], [List] or [Map] value.
    *
    * Returns true if the value is one of these types, and false if not.
    * If a value is both a [List] and a [Map], it's serialized as a [List].
    */
   bool stringifyJsonValue(final object) {
     if (object is num) {
       // TODO: use writeOn.
       sb.add(numberToString(object));
       return true;
-    } else if (object === true) {
+    } else if (identical(object, true)) {
       sb.add('true');
       return true;
-    } else if (object === false) {
+    } else if (identical(object, false)) {
       sb.add('false');
        return true;
-    } else if (object === null) {
+    } else if (object == null) {
       sb.add('null');
       return true;
     } else if (object is String) {
       sb.add('"');
       escape(sb, object);
       sb.add('"');
       return true;
     } else if (object is List) {
       checkCycle(object);
       List a = object;
@@ skipping 26 matching lines @@
         first = false;
       });
       sb.add('}');
       seen.removeLast();
       return true;
     } else {
       return false;
     }
   }
 }