add sign and trunc

source/Ox/js/Math.js

@@ -147,6 +147,21 @@ Ox.round = function(number, decimals) {
     return Math.round(number * pow) / pow;
 };
 
+/*@
+Ox.sign <f> Returns the sign of a number (-1, 0 or 1)
+    > Ox.sign(-Infinity)
+    -1
+    > Ox.sign(-0)
+    0
+    > Ox.sign(0)
+    0
+    > Ox.sign(Infinity)
+    1
+@*/
+Ox.sign = function(x) {
+    return x !== x || x === 0 ? x : x < 0 ? -1 : 1;
+};
+
 /*@
 Ox.sinh <f> Hyperbolic sine
     Missing from `Math`.
@@ -164,3 +179,12 @@ Ox.tanh <f> Hyperbolic tangent
 Ox.tanh = function(x) {
     return (Math.exp(x) - Math.exp(-x)) / (Math.exp(x) + Math.exp(-x));
 };
+
+/*@
+Ox.trunc <f> Truncates a number
+    > Ox.trunc(-1.5)
+    -1
+@*/
+Ox.trunc = function(x) {
+    return ~~x;
+};