[parser] adding support for expressions

src/test.node

@@ -1,7 +1,14 @@
-node slfjsdfj (i1: bool; i2, i3: int) returns (o, o_ : int);
-var l1, l3: bool; l2: int;
+node diagonal_int (i: int) returns (o1, o2 : int);
 let
-	pat1 = expr1;
-	pat2 = expr2;
-	pat3 = expr3;
+	o1 = if true then i else 0;
+	o2 = i;
+	(o1, o2) = (i, i);
+tel
+
+node undiag_test (i: int) returns (o : bool);
+var l1, l2: int; l3: int;
+let
+	l3 = 1 -> 0;
+	(l1, l2) = diagonal_int(i);
+	o = (not (not (l1 = l2))) and (l1 = l2) and true;
 tel