Re: scm_bits_t / scm_ubits_t

[Marius Vollmer]

Dirk Herrmann <address@hidden> writes:

> due to a recent change, we have a scm_ubits_t type in guile, that is meant
> to represent an unsigned form of scm_bits_t.  IMO, this is not a good
> idea:  We should rather guarantee, that scm_bits_t itself is already an
> unsigned value.

Yes.  I agree that having scm_ubits_t is not the right thing.
scm_bits_t is not a numerical type where it makes sense to talk about
signedness.

Moreover, I think I want to reserve judgment about the whole change.
For example, this

        * list.c (scm_ilength): return a scm_bits_t, not long.
        some other {int,long} -> scm_bits_t changes.

seems not quite right.  Either, scm_ilength ought to return ssize_t,
or if ssize_t has not the right semantics (i.e, being able to
enumerate all distinct objects pointable to from a `char*', which
might not be the same as being able to represent the size of every
possible object), we should define our own type for this.  scm_bits_t
should be only used for unpacked SCM values, to avoid confusion.  Just
as Dirk says.