Add a module for general functional programming stuff

fun.js

@@ -0,0 +1,64 @@
+function Fun() {
+	return {
+		defaultCompare: defaultCompare,
+		defined: defined,
+		insert: insert,
+		map: map,
+		mapFilter: mapFilter,
+		of: of,
+		proj: proj
+	};
+
+	function insert(obj, t, compare, min, max) {
+		min = min == undefined ? 0 : min;
+		max = max == undefined ? t.length : max;
+		compare = compare == undefined ? defaultCompare : compare;
+		if(max - min < 1) {
+			return min;
+		}
+		var avg = Math.floor((max + min) / 2);
+		if (compare(obj, t[avg]) < 0) {
+			return insert(obj, t, compare, min, avg);
+		} else {
+			return insert(obj, t, compare, avg+1, max);
+		}
+	}
+
+	function defaultCompare(a, b) {
+		if(a < b) {
+			return -1;
+		} else if(a > b) {
+			return 1;
+		} else {
+			return 0;
+		}
+	}
+
+	function map(mapper, f) {
+		return function() {
+			var args = Array.prototype.map.call(arguments, mapper);
+			return f.apply(null, args);
+		}
+	}
+
+	function of(o) {
+		return function(key) {return o[key];};
+	}
+
+	function proj(key) {
+		return function(o) {return o[key];};
+	}
+
+	function mapFilter(mapper, predicate) {
+		return function(array) {
+			return array.reduce(function(accumulator, elem) {
+				var v = mapper(elem);
+				return predicate(v) ? accumulator.concat(v) : accumulator;
+			}, []);
+		};
+	}
+
+	function defined(x) {
+		return x != undefined;
+	}
+}