Declare Variable Even and Use floor and Ceil

Hello,

I have come across a small missing thing; let me illustrate.

If I do
    (%i1) declare(e,even)$ floor(e/2);
Maxima will answer
    (%o1) e/2
which is very nice. (Maple can't do that for instance!)

However, if I do
    (%i2) declare(o,odd)$ floor(o/2);
I would expect Maxima to do
    (%w1) (o-1)/2
but Maxima answers simply
    (%o2) floor(o/2)

Likewise, I would expect
    (%i3) ceil(e/2); ceil(o/2);
to give
    (%w3) e/2
    (%w4) (o+1)/2
but Maxima answers
    (%o3) ceil(e/2)
    (%o4) ceil(o/2)

I spend some time grep'ing the source trying to figure out where and how
to apply these changes, but I came to the conclusion that it'd probably
be much more efficient (for all of us) if I just explained my point
rather than trying to create a diff.

It is probably the same evaluation difference between floor and ceil
that makes this:
    (%i1) declare(i,integer)$ floor(i); ceil(i);
    (%o2) i
    (%o3) ceil(i)


Greetings,
--
Casper Thomsen