Add is operator (#129)

TestHScript.hx

@@ -131,6 +131,38 @@ class TestHScript extends TestCase {
 		assertScript("pt2?.pt?.x", 10, vars);
 	}
 
+	function testIsOperator():Void {
+		var vars = {
+			String: String,
+			Bool: Bool,
+			Int: Int,
+			Float: Float,
+			Dynamic: Dynamic
+		}
+		assertScript("10 is Int", true, vars);
+		assertScript("10.0 is Int", true, vars);
+		assertScript("10.1 is Int", false, vars);
+		assertScript("10 is Float", true, vars);
+		assertScript("10.0 is Float", true, vars);
+		assertScript("10.1 is Float", true, vars);
+		assertScript("10 is String", false, vars);
+		assertScript('"hscript" is String', true, vars);
+		assertScript('"" is String', true, vars);
+		assertScript('true is Bool', true, vars);
+		assertScript('false is Bool', true, vars);
+		assertScript('0 is Bool', false, vars);
+		assertScript('1 is Bool', false, vars);
+		assertScript('1 is Bool', false, vars);
+		assertScript("10 is Dynamic", true, vars);
+		assertScript("10.1 is Dynamic", true, vars);
+		assertScript('"hscript" is Dynamic', true, vars);
+		assertScript('null is Int', false, vars);
+		assertScript('null is Float', false, vars);
+		assertScript('null is String', false, vars);
+		assertScript('null is Bool', false, vars);
+		assertScript('null is Dynamic', false, vars);
+	}
+
 	function testMap():Void {
 		var objKey = { ok:true };
 		var vars = {

hscript/Interp.hx

@@ -116,6 +116,7 @@ class Interp {
 		binops.set("&&",function(e1,e2) return me.expr(e1) == true && me.expr(e2) == true);
 		binops.set("=",assign);
 		binops.set("...",function(e1,e2) return new #if (haxe_211 || haxe3) IntIterator #else IntIter #end(me.expr(e1),me.expr(e2)));
+		binops.set("is",function(e1,e2) return #if (haxe_ver >= 4.2) Std.isOfType #else Std.is #end (me.expr(e1), me.expr(e2)));
 		assignOp("+=",function(v1:Dynamic,v2:Dynamic) return v1 + v2);
 		assignOp("-=",function(v1:Float,v2:Float) return v1 - v2);
 		assignOp("*=",function(v1:Float,v2:Float) return v1 * v2);

hscript/Parser.hx

@@ -804,6 +804,8 @@ class Parser {
 				return parseExprNext(mk(EUnop(op,false,e1),pmin(e1)));
 			}
 			return makeBinop(op,e1,parseExpr());
+		case TId(op) if ( op == 'is' ):
+			return makeBinop(op,e1,parseExpr());
 		case TDot:
 			var field = getIdent();
 			return parseExprNext(mk(EField(e1,field),pmin(e1)));