Merge pull request #761 from ePaul/feature/add-Integer.nearestFloat

Issue #759: Add attribute Integer.nearestFloat.

runtime-js/Integer/nearestFloat.js

@@ -0,0 +1 @@
+return Float(this.valueOf());

runtime/ceylon/language/Integer.java

@@ -428,6 +428,15 @@ public static double getFloat(long value) {
         }
     }
 
+    public double getNearestFloat() {
+        return (double) value;
+    }
+
+    @Ignore
+    public static double getNearestFloat(long value) {
+        return (double) value;
+    }
+
     public byte getByte() {
         return getByte(value);
     }

src/ceylon/language/Integer.ceylon

@@ -150,7 +150,17 @@ shared native final class Integer(Integer integer)
              this.magnitude>runtime.maxExactIntegralFloat")
     see (`value runtime.maxExactIntegralFloat`)
     shared native Float float;
-
+
+    "The nearest [[Float]] to this number. For
+     Integers in magnitude less than 2^53, this is always
+     a Float with the exact same mathematical value (and the
+     same value as [[float]]), for larger ones on the JVM the
+     Floats are less dense than the Integers so there can be some
+     loss of precision.
+
+     This method never throws an OverflowException."
+    shared native Float nearestFloat;
+
     shared actual native Integer predecessor;
     shared actual native Integer successor;
     shared actual native Integer neighbour(Integer offset);

test/numbers.ceylon

@@ -181,6 +181,20 @@ shared void numbers() {
     check((-1.1).integer==-1, "(-1.1).integer is `` (-1.1).integer `` instead of -1");
     check(2.float==2.0, "integer float");
     check((-3).float==-3.0, "negative integer float");
+    check(2.nearestFloat==2.0, "small integer nearestFloat");
+    check((-3).nearestFloat==-3.0, "small negative integer nearestFloat");
+
+
+
+    try {
+       fail("Should have thrown Overflow Exception: ``922337203685477632.float``");
+    } catch(OverflowException ex) {
+        check(ex.message == "922337203685477632 cannot be coerced into a 64 bit floating point value");
+    }
+
+    check(922337203685477632.nearestFloat == 9.2233720368547763E17, "large nearest float 1");
+    check((-922337203685477632).nearestFloat == -9.2233720368547763E17, "large negative nearest float");
+    check(922337203685477635.nearestFloat == 9.2233720368547763E17, "large nearest float 2");
 
     check(1.plus { other=2; }.equals { that=3; }, "natural named args");