Make ~/, round, ceil, floor, truncate return ints. Remove toInt.

sdk/lib/_internal/compiler/implementation/lib/js_number.dart

Index: sdk/lib/_internal/compiler/implementation/lib/js_number.dart
diff --git a/sdk/lib/_internal/compiler/implementation/lib/js_number.dart b/sdk/lib/_internal/compiler/implementation/lib/js_number.dart
index 6acf7696feef9b2df4fe6ee65bc927195b90d985..bfc3343e46ee96745050a5b346b134a5eb0138e9 100644
--- a/sdk/lib/_internal/compiler/implementation/lib/js_number.dart
+++ b/sdk/lib/_internal/compiler/implementation/lib/js_number.dart
@@ -49,28 +49,36 @@ class JSNumber {
 
   num abs() => JS('num', r'Math.abs(#)', this);
 
-  int toInt() {
+  num ceil() {
     if (isNaN) throw new FormatException('NaN');

[Lasse Reichstein Nielsen, 2013/01/04 10:29:42]

Consider UnsupportedError.
FormatException is really for when you pass something to a parse-function and
checking the format is just as complicated as actually parsing.
UnsupportedError doesn't fit exactly (it talks about the class not supporting
the operation, not just the value), so perhaps we should change its description.

     if (isInfinite) throw new FormatException('Infinity');

[Lasse Reichstein Nielsen, 2013/01/04 10:29:42]

Consider combining the test into one 'Not finite' error. Saves time.

-    num truncated = truncate();
-    return JS('bool', r'# == -0.0', truncated) ? 0 : truncated;
+    num ceiled = JS('num', r'Math.ceil(#)', this);

[Lasse Reichstein Nielsen, 2013/01/04 10:29:42]

Just do:
  return JS('num', r'Math.ceil(#) + 0', this);

+    return (ceiled == -0.0) ? 0 : ceiled;
   }
 
-  num ceil() => JS('num', r'Math.ceil(#)', this);
-
-  num floor() => JS('num', r'Math.floor(#)', this);
+  num floor() {
+    if (isNaN) throw new FormatException('NaN');
+    if (isInfinite) throw new FormatException('Infinity');
+    JS('num', r'Math.floor(#)', this);

[Lasse Reichstein Nielsen, 2013/01/04 10:29:42]

This can return -0 if it gets -0 as input. Add the +0 here too.

+  }
 
-  bool get isInfinite {
-    return JS('bool', r'# == Infinity', this)
-      || JS('bool', r'# == -Infinity', this);
+  int truncate() {
+    return this < 0 ? ceil() : floor();

[Lasse Reichstein Nielsen, 2013/01/04 10:29:42]

Parentheses around (this < 0).

   }
 
   num round() {
-    if (this < 0) {
-      return JS('num', r'-Math.round(-#)', this);
-    } else {
-      return JS('num', r'Math.round(#)', this);
+    if (isNaN) throw new FormatException('NaN');
+    if (isInfinite) throw new FormatException('Infinity');
+    if (this <= 0) {
+      num rounded = JS('num', r'-Math.round(-#)', this);

[Lasse Reichstein Nielsen, 2013/01/04 10:29:42]

Just do 
  return JS('int', r'-Math.round(-#) + 0', this);

+      return (rounded == -0.0) ? 0 : rounded;
     }
+    return JS('num', r'Math.round(#)', this);
+  }
+
+  bool get isInfinite {
+    return JS('bool', r'# == Infinity', this)
+      || JS('bool', r'# == -Infinity', this);

[Lasse Reichstein Nielsen, 2013/01/04 10:29:42]

Indentation off here.

   }
 
   num clamp(lowerLimit, upperLimit) {
@@ -86,8 +94,6 @@ class JSNumber {
 
   double toDouble() => this;
 
-  num truncate() => this < 0 ? ceil() : floor();
-
   String toStringAsFixed(int fractionDigits) {
     checkNum(fractionDigits);
     // TODO(floitsch): fractionDigits must be an integer.