Re: [perl #31987] Should predefined pmcs inherit nci methods?

[Sam Ruby]

Dan Sugalski wrote:
At 9:33 AM -0400 10/15/04, Sam Ruby wrote:
Leopold Toetsch wrote:
Sam Ruby <[EMAIL PROTECTED]> wrote:
Concrete example: should ResizablePMCArray inherit sort from 
FixedPMCArray?
Yes. But the inheritance should be (and is AFAIK already partially) in
the method lookup. But it's not quite finished. Objects derived from
PMCs inherit methods of the parent, but one level only. PMC inheritance
isn't followed yet IIRC.
I'm puzzled as to what works and what doesn't work.  I added a __add__ 
method to pyobject and I can't access it from pyint... however I can 
access sort from ResizablePMCArray.  Weird.
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. These methods are the *C* 
methods (not NCI or bytecode) and they get filled in at parrot build 
time. There's no runtime inheritance, lookups, or anything. The fixed 
method is what's called. (That the fixed method may then delegate to 
parrot methods confounds things a bit)

The second is the *parrot* method stuff. These generally do a search of 
the hierarchy, at least if you're making a method call on a thing that's 
a ParrotObject. If you're making a method call on something else it 
depends on whether the method invocation code for that thing knows how 
to traverse the hierarchy.

So basically it's a bit of a muddle, and it needs swamping out.
It still doesn't make sense to me.  Try adding the following line to 
both fixedpmcarray.pmc and perlint.pmc:

  METHOD INTVAL inheritme() { return 42; }
Then try running the following:
  .sub _main @MAIN
      print "test 1\n"
      $P0 = new ResizablePMCArray
      $I1 = $P0."inheritme"()
      print $I1
      print "\n"
      print "test 2\n"
      $P0 = new Boolean
      $I1 = $P0."inheritme"()
      print $I1
      print "\n"
  .end
The output I get is:
  test 1
  42
  test 2
  Method 'inheritme' not found
          in file '(unknown file)' near line -1
Apparently FixedPMCArray and PerlInt are different kinds of classes?
In any case, I would like to create some PMCs to represent Python 
classes.  And I would like to implement as many of the methods as I can 
in C.  And I would like such methods to be inherited.

I'm OK with a temporary solution (like the patch I provided) until a 
"real" solution can be put in place.

Suggestions welcome.
[1] And yes, I am being dragged deep into objects. Kicking and 
screaming, but still..
- Sam Ruby