Add isFinite getter to num.

sdk/lib/core/num.dart

Index: sdk/lib/core/num.dart
diff --git a/sdk/lib/core/num.dart b/sdk/lib/core/num.dart
index 1ef0e16e8dece8d0bc1eb033718785c6a69781e6..d61a0244a505175c17acf42457c572fc20ea7c37 100644
--- a/sdk/lib/core/num.dart
+++ b/sdk/lib/core/num.dart
@@ -142,12 +142,28 @@ abstract class num implements Comparable<num> {
   /** Relational greater than or equal operator. */
   bool operator >=(num other);
 
+  /** Whether the number is the double Not-a-Number value. */
   bool get isNaN;
 
+  /**
+   * Whether the number is negative.
+   *
+   * Negative numbers are those less than zero, and the double `-0.0`.
+   */
   bool get isNegative;
 
+  /**
+   * Whether the number is the double positive or negative infinity.

[floitsch, 2013/10/18 11:54:59]

double reads bad here.

[Lasse Reichstein Nielsen, 2013/10/23 10:21:38]

Done.

+   */
   bool get isInfinite;
 
+  /**
+   * Whether the number is finite.
+   *
+   * The only non-finite numbers are NaN and positive or negative infinity.

[floitsch, 2013/10/18 11:54:59]

nit. I prefer:
NaN, positive infinity and negative infinity.

[Lasse Reichstein Nielsen, 2013/10/23 10:21:38]

Done.

+   */
+  bool get isFinite;
+
   /** Returns the absolute value of this [num]. */
   num abs();