lispy.c

lval* builtin_join_str(lenv* e, lval* a) {
  for(int i = 0; i < a->count; i++) {
    LASSERT_TYPE("join", a, i, LVAL_STR);
  }

  lval* x = lval_pop(a, 0);

  while (a->count) {
    lval* y = lval_pop(a, 0);
    char* concatted = malloc(strlen(x->str) + strlen(y->str) + 1);
    concatted = strcat(x->str, y->str);
    x = lval_str(concatted);

    free(concatted);
    free(y);
  }

  lval_del(a);
  return x;
}