[pypy-dev] Support for __getitem__ in rpython?

[Hakan Ardo]

Hi,
I've started to play around with the pypy codebase with the intention
to make obj[i] act like obj.__getitem__(i) for rpython objects.  The
approach I tried was to add:

 class __extend__(pairtype(SomeInstance, SomeObject)):
     def getitem((s_array, s_index)):
         s=SomeString()
         s.const="__getitem__"
         p=s_array.getattr(s)
         return p.simple_call(s_index)

and then do something like:

 class __extend__(pairtype(AbstractInstanceRepr, Repr)):
     def rtype_getitem((r_array, r_key), hop):
         hop2=hop.copy()
         ...
         hop2.forced_opname = 'getattr'
         hop2.dispatch()
         hop3=hop.copy()
         ...
         hop3.forced_opname = 'simple_call'
         hop3.dispatch()

But I am having a hard time understanding the rtyper and if this is
the right approach?  Is there anything similar in the code/docs I
could look at to get a better understanding on how to write this?
Would it be a better solution to add an intermediate step between the
annotator and the rtyper that converts
getitem(SomeInstance,SomeObject) into
vx=getattr(SomeInstance,'__getitem__'); simple_call(vx,SomeObject)?

Any suggestions will be appreciated. Thanx!

--
Håkan Ardö