Fix issue: 5427703 (compareTo), fix parsing of -0.0.

runtime/lib/double.dart

 // 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.
 
 class Double implements double {
   factory Double.fromInteger(int value)
       native "Double_doubleFromInteger";
   int hashCode() {
     try {
       return toInt();
@@ skipping 85 matching lines @@
   }
   bool isOdd() {
     // TODO(floitsch): find more efficient way to implement Double.isOdd.
     return this % 2.0 == 1.0;
   }
   bool isNegative() native "Double_isNegative";
   bool isInfinite() native "Double_isInfinite";
   bool isNaN() native "Double_isNaN";
 
   double abs() {
+    // Handle negative 0.0.
+    if (this == 0.0) return 0.0;  
     return this < 0.0 ? -this : this;
   }
 
   double round() native "Double_round";
   double floor() native "Double_floor";
   double ceil () native "Double_ceil";
   double truncate() native "Double_truncate";
   int toInt() native "Double_toInt";
   double toDouble() { return this; }
 
@@ skipping 16 matching lines @@
 
     // Step 4.
     if (x.isNaN()) {
       return "NaN";
     }
 
     // Step 5.
     String s = "";
 
     // Step 6.
-    if (x.isNegative()) {
+    if (x.isNegative() && x != 0.0) {
       s = "-";
       x = -x;
     }
 
     // Step 7.
     String m;
     if (x > 10e21) {
       m = x.toString();
     } else {
       // Step 8.
@@ skipping 32 matching lines @@
   }
   String toStringAsExponential(int fractionDigits) {
     throw "Double.toStringAsExponential unimplemented.";
   }
   String toStringAsPrecision(int precision) {
     throw "Double.toStringAsPrecision unimplemented.";
   }
   String toRadixString(int radix) {
     throw "Double.toRadixString unimplemented.";
   }
+
+  // Order is: NaN > Infinity > ... > 0.0 > -0.0 > ... > -Infinity.
   int compareTo(Comparable other) {
-    if (this == other) return 0;
-    if (this < other) return -1;
-    return 1;
+    final int EQUAL = 0, LESS = -1, GREATER = 1;
+    if (this < other) {
+      return LESS;
+    } else if (this > other) {
+      return GREATER;
+    } else if (this == other) {
+      if (this == 0.0) {
+        bool thisIsNegative = isNegative();
+        bool otherIsNegative = other.isNegative();
+        if (thisIsNegative == otherIsNegative) {
+          return EQUAL;
+        }
+        return thisIsNegative ? LESS : GREATER;
+      } else {
+        return EQUAL;
+      }
+    } else if (isNaN()) {
+      return other.isNaN() ? EQUAL : GREATER;
+    } else {
+      // Other is NaN.
+      return LESS;
+    }
   }
 }