Implemented the nullish concatenation and assignment operators.

Implemented the missing logical operation plus assignment.


git-svn-id: http://yate.null.ro/svn/yate/trunk@6504 acf43c95-373e-0410-b603-e72c3f656dc1

libs/yscript/evaluator.cpp

@@ -44,6 +44,10 @@ static const TokenDict s_operators_c[] =
     ASSIGN("&", And),
     ASSIGN("|", Or),
     ASSIGN("^", Xor),
+    ASSIGN("&&",LAnd),
+    ASSIGN("||",LOr),
+    ASSIGN("^^",LXor),
+    ASSIGN("??",Nullish),
     MAKEOP("<<",Shl),
     MAKEOP(">>",Shr),
     MAKEOP("==",Eq),
@@ -55,6 +59,7 @@ static const TokenDict s_operators_c[] =
     MAKEOP("&&",LAnd),
     MAKEOP("||",LOr),
     MAKEOP("^^",LXor),
+    MAKEOP("??",Nullish),
     MAKEOP("+", Add),
     MAKEOP("-", Sub),
     MAKEOP("*", Mul),
@@ -1266,6 +1271,25 @@ bool ExpEvaluator::runOperation(ObjList& stack, const ExpOperation& oper, GenObj
 		TelEngine::destruct(op);
 	    }
 	    break;
+	case OpcNullish:
+	    {
+		ExpOperation* op2 = popValue(stack,context);
+		ExpOperation* op1 = popValue(stack,context);
+		if (!op1 || !op2) {
+		    TelEngine::destruct(op1);
+		    TelEngine::destruct(op2);
+		    return gotError("ExpEvaluator stack underflow",oper.lineNumber());
+		}
+		if (JsParser::isMissing(*op1)) {
+		    TelEngine::destruct(op1);
+		    pushOne(stack,op2);
+		}
+		else {
+		    TelEngine::destruct(op2);
+		    pushOne(stack,op1);
+		}
+	    }
+	    break;
 	case OpcFunc:
 	    return runFunction(stack,oper,context) ||
 		gotError("Function '" + oper.name() + "' call failed",oper.lineNumber());

libs/yscript/yatescript.h

@@ -311,6 +311,8 @@ public:
 	OpcLabel,   // ( --- )
 	// Push with deep copy
 	OpcCopy,    // ( --- CopiedA)
+	// Nullish coalescing
+	OpcNullish, // (A B --- A??B)
 	// Field assignment - can be ORed with other binary operators
 	OpcAssign  = 0x0100, // (A B --- B,(&A=B))
 	// Private extension area for derived classes