Han-Wen Nienhuys skrev:
+ SCM virtual_smobbed_copy () { // AAARGH!
+ return smobbed_copy ();
+ }
for this, we usually have a clone() method, see the
VIRTUAL_COPY_CONSTRUCTOR method; so I suggest to use a smobbed_clone()
function.
DECLARE_SIMPLE_SMOBS (Pitch);
This looks bad. You have to remove Pitch as a smobtype, and then
create an unsmob_pitch, which does
dynamic_cast<Pitch*> (unsmob_pitchclass (obj))
That won't work with simple smobs.
Why? It should work if have virtual methods.
I feel a bit stupid now, sorry, but IMPLEMENT_SIMPLE_SMOBS does
SCM CL::smobbed_copy () const
{
CL *ptr = new CL (*this);
SCM s;
s = scm_cons (SCM_PACK (CL::smob_tag_), SCM_PACK (ptr));
scm_gc_register_collectable_memory ((CL *)this, sizeof (CL), #CL "
smob");
return s;
}
So it is hardcoded that the normal non-virtual copy-constructor is used
to generate the smob.
And it is hardcoded that the SCM should only use memory at the sizeof
Pitchclass. If I stuff a Pitch in there won't we get severe trouble
because it takes up more heap space than what the SCM memory management
thinks?
Sorry for me being stupid.
Suppose you have x,
which is a pitch smob. Then you have function f which takes a
pitchclass. From the scheme side of things, it's not clear that f can
be applied to x, since x has a different type.
Hmm, so what you say is that we should not allow scheme functions that
work on both pitch and pitchclass?
I don't like this - the whole idea of the pitchclass-pitch-thing is that
the key signature contains both pitches and pitchclasses. The scheme
programmer should be supplied with high-level-functions that compares
pitches and pitchclasses in the right way - no matter whether they are
pitches or pitchclassses. This will be ruined if he is not allowed to
stuff pitches and pitchclasses into the same function.
For instance we have
LY_DEFINE (ly_pitch_octave, "ly:pitch-octave",
1, 0, 0, (SCM pp),
"Extract the octave from [EMAIL PROTECTED]@var{pp}.")
{
Pitch *p = unsmob_pitch (pp);
if(p==NULL)
{
LY_ASSERT_SMOB (Pitchclass, pp, 1);
return SCM_BOOL_F;
}
int q = p->get_octave ();
return scm_from_int (q);
}
The scheme function that returns the octave from a pitch, or #f from a
pitchclass.
-Rune
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