feat: Null-safe field assign

Author: NotHyper-474

TestHScript.hx

@@ -125,12 +125,12 @@ class TestHScript extends TestCase {
 		assertScript("var f:(x:Int)->(Int, Int)->Int = (x:Int) -> (y:Int, z:Int) -> x + y + z; f(3)(1, 2)", 6, null, true);
 		assertScript("var a = 10; var b = 5; a - -b", 15);
 		assertScript("var a = 10; var b = 5; a - b / 2", 7.5);
-		assertScript("var a; a", null);
-		assertScript("var a = 1, b = 5; a + b;", 6);
-		assertScript("var a, b = 5; if (a == null) a = 2; a + b;", 7);
-		assertScript("var a:Int; a", null, null, true);
-		assertScript("var a:Int = 1, b:Int = 5; a + b;", 6, null, true);
-		assertScript("var a:Int, b:Int = 5; if (a == null) a = 2; a + b;", 7, null, true);
+		assertScript("var a; a", null);
+		assertScript("var a = 1, b = 5; a + b;", 6);
+		assertScript("var a, b = 5; if (a == null) a = 2; a + b;", 7);
+		assertScript("var a:Int; a", null, null, true);
+		assertScript("var a:Int = 1, b:Int = 5; a + b;", 6, null, true);
+		assertScript("var a:Int, b:Int = 5; if (a == null) a = 2; a + b;", 7, null, true);
 		assertScript("false && xxx", false);
 		assertScript("true || xxx", true);
 		assertScript("[for( x in arr ) switch( x ) { case 1: 55; case 3: 66; default: 0; }].join(':')",'55:0:66',{ arr : [1,2,3] });
@@ -142,14 +142,20 @@ class TestHScript extends TestCase {
 			ptnull : null,
 			pt: pt,
 			pt2null : {pt : null},
-			pt2: {pt : pt}
+			pt2: {pt : pt},
+			str: 'getting freaky on a friday night yeah'
 		}
 		assertScript("ptnull?.x", null, vars);
 		assertScript("pt?.x", 10, vars);
 		assertScript("pt2null?.pt", null, vars);
 		assertScript("pt2null?.pt?.x", null, vars);
 		assertScript("pt2?.pt", pt, vars);
 		assertScript("pt2?.pt?.x", 10, vars);
+		assertScript("ptnull?.x = 5", null, vars);
+		assertScript("pt2null?.pt?.x = 5", null, vars);
+		assertScript("pt2?.pt?.x = 2", 2, vars);
+		assertScript("str?.indexOf('freaky')", 8, vars);
+		assertScript("ptnull?.indexOf('friday')", null, vars);
 	}
 
 	function testIsOperator():Void {
@@ -256,4 +262,4 @@ class TestHScript extends TestCase {
 		#end
 	}
 
-}
+}

hscript/Parser.hx

@@ -822,27 +822,27 @@ class Parser {
 			return parseExprNext(mk(EField(e1,field),pmin(e1)));
 		case TQuestionDot:
 			var field = getIdent();
+
+			if (maybe(TOp('='))) {
+				var e2 = parseExpr();
+				var e = mk(EIf(
+					mk(EBinop("!=", e1, mk(EIdent("null"), pmin(e1), pmax(e1))), pmin(e1), pmax(e1)),
+					mk(EBinop("=", mk(EField(e1, field), pmin(e1), pmax(e1)), e2), pmin(e1), pmax(e2))
+				), pmin(e1), pmax(e2));
+				return parseExprNext(e);
+			}
+
 			var tmp = "__a_" + (uid++);
 			var e = mk(EBlock([
 				mk(EVar(tmp, null, e1), pmin(e1), pmax(e1)),
 				mk(ETernary(
 					mk(EBinop("==", mk(EIdent(tmp),pmin(e1),pmax(e1)), mk(EIdent("null"),pmin(e1),pmax(e1)))),
 					mk(EIdent("null"),pmin(e1),pmax(e1)),
+					maybe(TPOpen) ? mk(ECall(mk(EField(mk(EIdent(tmp),pmin(e1),pmax(e1)),field),pmin(e1)),parseExprList(TPClose)),pmin(e1)) :
 					mk(EField(mk(EIdent(tmp),pmin(e1),pmax(e1)),field),pmin(e1))
 				))
 			]),pmin(e1));
 
-			if ( maybe(TPOpen) ) {
-				e = mk(EBlock([
-					mk(EVar(tmp, null, e1), pmin(e1), pmax(e1)),
-					mk(ETernary(
-						mk(EBinop("==", mk(EIdent(tmp),pmin(e1),pmax(e1)), mk(EIdent("null"),pmin(e1),pmax(e1)))),
-						mk(EIdent("null"),pmin(e1),pmax(e1)),
-						mk(ECall(mk(EField(mk(EIdent(tmp),pmin(e1),pmax(e1)),field),pmin(e1)),parseExprList(TPClose)),pmin(e1))
-					))
-				]),pmin(e1));
-			}
-
 			return parseExprNext(e);
 		case TPOpen:
 			return parseExprNext(mk(ECall(e1,parseExprList(TPClose)),pmin(e1)));