+ let_stmt *let;
+ decl_arg *darg = let->var->arg;
+ decl *decl_cb = darg->type->func;
+ let_callback *cb = let->val->data.callback;
+ impl_arg *iarg = cb->func->arg;
+ size_t i, argc = cb->args->count;
+ zval return_value, *argv = calloc(argc, sizeof(*argv));