feat: add exit builtin function

include/common/fzl_builtins.h

@@ -3,7 +3,8 @@
 
 typedef enum
 {
-  FZL_BUILTIN_PRINTLINE // Print message in arg with newline at end
+  FZL_BUILTIN_PRINTLINE, // Print message in arg with newline at end
+  FZL_BUILTIN_EXIT,      // Exit program with code specified in arg
 } fzl_builtin_t;
 
 #endif // FZL_BUILTINS_H

src/compiler/fzl_walker.c

@@ -754,6 +754,30 @@ fzl_walk_res_t walk(fzl_walker_t *walker, fzl_node_t *node)
           }
           current_res = (fzl_walk_res_t){.type = FZL_TYPE_NULL, .error = false};
         }
+        else if (strcmp(node->token->value, "exit") == 0)
+        {
+          if (node->call.args_count > 0)
+          {
+            for (size_t i = 0; i < node->call.args_count; i++)
+            {
+              fzl_walk_res_t res = walk(walker, node->call.args[i]);
+              if (res.error)
+                return res;
+            }
+
+            push_op(walker, FZL_OPCODE_CALL_BUILTIN);
+            push_word(walker, FZL_BUILTIN_EXIT);
+            if (node->call.args_count < 1)
+            {
+              snprintf(wlast_err, sizeof(wlast_err),
+                       "'%s': 'exit' call with zero arguments at %ld:%ld",
+                       node->token->filename, node->token->ln, node->token->cn);
+              return (fzl_walk_res_t){.error = true, .error_msg = wlast_err};
+            }
+            current_res =
+                (fzl_walk_res_t){.type = FZL_TYPE_NULL, .error = false};
+          }
+        }
         else
         {
           if (node->call.callee->type == FZL_NODETYPE_IDENTIFIER)
@@ -778,8 +802,9 @@ fzl_walk_res_t walk(fzl_walker_t *walker, fzl_node_t *node)
             if (!found)
             {
               snprintf(wlast_err, sizeof(wlast_err),
-                       "call to unknown function '%s'",
-                       (char *)node->token->value);
+                       "'%s': call to unknown function '%s' at %ld:%ld",
+                       node->token->filename, (char *)node->token->value,
+                       node->token->ln, node->token->cn);
               return (fzl_walk_res_t){.error = true, .error_msg = wlast_err};
             }
 

src/vm/fzl_vm.c

@@ -538,8 +538,8 @@ int fzl_vm_run(fzl_vm_t *vm)
           return -1;
         }
 
-        fzl_value_t llt = vm->dstack[--vm->dtop];
         fzl_value_t rlt = vm->dstack[--vm->dtop];
+        fzl_value_t llt = vm->dstack[--vm->dtop];
         vm->dstack[vm->dtop++] =
             (fzl_value_t){.type = FZL_TYPE_BOOL, .as.b = llt.as.u < rlt.as.u};
         break;
@@ -769,6 +769,11 @@ int fzl_vm_run(fzl_vm_t *vm)
           else if (arg.type == FZL_TYPE_OBJECT)
             print_object(arg.as.obj);
         }
+        else if (fn_id == FZL_BUILTIN_EXIT)
+        {
+          fzl_value_t arg = vm->dstack[--vm->dtop];
+          exit(arg.as.i);
+        }
         else
         {
           snprintf(last_err, sizeof(last_err),