fix the unary not (logical not) handling for issue #5, add tests

expression.c

@@ -761,23 +761,25 @@ void ExpressionPrefixOperator(struct ParseState *Parser,
                 ProgramFail(Parser, "can't assign to this");
             switch (Op) {
             case TokenIncrement:
-                TopValue->Val->Pointer =
+                ResultPtr = TopValue->Val->Pointer =
                     (void*)((char*)TopValue->Val->Pointer+Size);
                 break;
             case TokenDecrement:
-                TopValue->Val->Pointer =
+                ResultPtr = TopValue->Val->Pointer =
                     (void*)((char*)TopValue->Val->Pointer-Size);
                 break;
             case TokenUnaryNot:
-                /* conditionally checking a pointer's value */
+                /* conditionally checking a pointer's value, we only want
+                    to change the stack value (ResultPtr) and not the pointer's
+                    actual value  */
                 TopValue->Val->Pointer =
-                    (void*)((TopValue->Val->Pointer) ? NULL : (void*)1);
+                    (void*)((char*)TopValue->Val->Pointer);
+                    ResultPtr = TopValue->Val->Pointer ? NULL : (void*)0x01;
                 break;
             default:
                 ProgramFail(Parser, "invalid operation");
                 break;
             }
-            ResultPtr = TopValue->Val->Pointer;
             StackValue = ExpressionStackPushValueByType(Parser, StackTop,
                 TopValue->Typ);
             StackValue->Val->Pointer = ResultPtr;

tests/08_while.c

@@ -3,6 +3,7 @@
 int a;
 int p;
 int t;
+int *pp;
 
 a = 1;
 p = 0;
@@ -16,4 +17,22 @@ while (a < 100)
     p = t;
 }
 
+a = 0;
+pp = NULL;
+while (!pp) {
+    printf("%d\n", a);
+    a += 1;
+    if (a == 8)
+    	pp = &a;
+}
+
+p = 10;
+pp = &p;
+while (pp) {
+    printf("%d\n", p);
+    p -= 1;
+    if (p == 2)
+    	pp = NULL;
+}
+
 void main() {}

tests/08_while.expect

@@ -9,3 +9,19 @@
 34
 55
 89
+0
+1
+2
+3
+4
+5
+6
+7
+10
+9
+8
+7
+6
+5
+4
+3