add null coalescing

Author: lemz1

hscript/Interp.hx

@@ -117,6 +117,7 @@ class Interp {
 		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)));
+		binops.set("??",function(e1,e2) return 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

@@ -115,7 +115,7 @@ class Parser {
 
 	public function new() {
 		line = 1;
-		opChars = "+*/-=!><&|^%~";
+		opChars = "+*/-=!><&|^%~?";
 		identChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_";
 		var priorities = [
 			["%"],
@@ -127,6 +127,7 @@ class Parser {
 			["..."],
 			["&&"],
 			["||"],
+			["??"],
 			["=","+=","-=","*=","/=","%=","<<=",">>=",">>>=","|=","&=","^=","=>"],
 			["->"]
 		];
@@ -140,7 +141,7 @@ class Parser {
 		for( i in 0...priorities.length )
 			for( x in priorities[i] ) {
 				opPriority.set(x, i);
-				if( i == 9 ) opRightAssoc.set(x, true);
+				if( i == 10 ) opRightAssoc.set(x, true);
 			}
 		for( x in ["!", "++", "--", "~"] ) // unary "-" handled in parser directly!
 			opPriority.set(x, x == "++" || x == "--" ? -1 : -2);
@@ -1508,6 +1509,8 @@ class Parser {
 				char = readChar();
 				if( char == ".".code )
 					return TQuestionDot;
+				if( char == "?".code )
+					return TOp("??");
 				this.char = char;
 				return TQuestion;
 			case ":".code: return TDoubleDot;