Dan Sugalski <[EMAIL PROTECTED]> wrote:
> There are two basic classes of methods here. (And classes of classes,
> something I'm regretting, and I think we'll redo once I get a handle
> on metaclasses and just unify it all)[1]
> The first is the vtable method stuff. There's a static single
> inheritance scheme when Parrot's built.
And a bit of hackish multiple inheritance. OrderedHash isa Array and isa
Hash. It's still static and not really supported by the PMC compiler
albeit needed.
E.g. a TclString isa tclobject (which handles morphing). OTOH it really
should be a String too: almost all worker functions are the same.
A usable scheme for multiple inheritance at the PMC level could vastly
reduce code multiplication and reduce implementation errors.
> The second is the *parrot* method stuff. These generally do a search
> of the hierarchy
And we have a third category: real objects that inherit from PMCs. E.g.
some snippets from the pie-thon tests:
# b3.py
...
T = int
class TT(T):
def __repr__(self):
return "T(%d)" % self
class Int(TT):
...
TT.__cmp__ = icmp
The C<int> thingy is a "PyInteger" PMC. C<TT> and C<Int> inherit from
it, e.g. the compare MMD function, which gets overridden in the middle
of the inheritance chain.
Which leads to a nice project called MMD inheritance ...
leo
