At Wed, 7 Sep 2011 20:18:44 -0400, Danny Yoo wrote:
> I'm looking at scheme_is_list in src/list.c, and it looks like there's
> code that's unreachable, unless I'm reading it wrong?! The body is:
>
>
> int scheme_is_list(Scheme_Object *obj1)
> {
> Scheme_Object *obj2;
> int flags;
>
> if (SCHEME_PAIRP(obj1)) {
> flags = SCHEME_PAIR_FLAGS(obj1);
> if (flags & PAIR_FLAG_MASK) {
> if (flags & PAIR_IS_LIST)
> return 1;
> else
> return 0;
> }
> } else if (SCHEME_NULLP(obj1))
> return 1;
> else
> return 0;
>
> obj2 = obj1;
>
> /** more code here */
> }
>
>
> Isn't all the code starting from 'obj2 = obj1' unreachable?
No --- the first `if' branch doesn't always return, since its returns
are protected by another `if'.
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