Swaack and error macro.

diff --git a/implementations/uvm-ncc/joy.c b/implementations/uvm-ncc/joy.c
index 9f85d12..4dff1dd 100644 (file)
--- a/implementations/uvm-ncc/joy.c
+++ b/implementations/uvm-ncc/joy.c
@@ -43,6 +43,11 @@ u64 error = 0;
 #define EXTRA_CLOSING_BRACKET 3
 #define CONS_HEAP_OOM 4
 #define STRING_HEAP_OOM 5
+#define NOT_ENOUGH_VALUES_ON_STACK 6
+#define NOT_A_LIST 7
+
+#define CHECK_ERROR if (error != NO_ERROR) return 0;
+
 
 /*
 char *error_messages[3] = {
@@ -112,7 +117,7 @@ cons(u32 head, u32 tail)
 {
        if (free >= HEAP_SIZE) {
                error = CONS_HEAP_OOM;
-               return -1;
+               return 0;
        }
        heads[free] = head;
        tails[free] = tail;
@@ -553,9 +558,21 @@ joy_eval(char *symbol, u32 stack, u32 expression)
 u64
 swaack(u32 stack, u32 expression)
 {
+       if (!stack) {
+               error = NOT_ENOUGH_VALUES_ON_STACK;
+               return 0;
+       }
+       u32 list = head(stack);
+       if (TYPE_OF(list) != joyList) {
+               error = NOT_A_LIST;
+               return 0;
+       }
+       stack = cons(tail(stack), list);
+       CHECK_ERROR
        return (u64)stack << 32 | expression;
 }
 
+
 u32
 joy(u32 stack, u32 expression)
 {
@@ -564,15 +581,10 @@ joy(u32 stack, u32 expression)
                term = head(expression);
                expression = tail(expression);
                if (TYPE_OF(term) == joySymbol) {
-
                        char *symbol = ht_lookup(VALUE_OF(term));
-                       if (error != NO_ERROR)
-                               return 0;
-
+                       CHECK_ERROR
                        u64 new_state = joy_eval(symbol, stack, expression);
-                       if (error != NO_ERROR)
-                               return 0;
-
+                       CHECK_ERROR
                        stack = new_state >> 32;
                        expression = new_state & 0xffffffff;
                }
@@ -610,11 +622,18 @@ main()
        print_endl();
        */
 
-       u32 expression = text_to_expression("1 2 3 clear 4 5 6");
+       u32 expression = text_to_expression("1 2 3 [4 5 6] swaack");
+       //u32 expression = text_to_expression("1 2 3 clear 4 5 6");
        //u32 expression = text_to_expression(" 1[2[true 3][aa[aa bb] aa bb cc]bob]false[]bob 3[4] ga[]ry");
        print_joy_list(expression);
        print_endl();
        u32 stack = joy(empty_list, expression);
-       print_joy_list(stack);
-       print_endl();
+       if (error) {
+               print_str("error: ");
+               print_i64(error);
+               print_endl();
+       } else {
+               print_joy_list(stack);
+               print_endl();
+       }
 }