--- On Tue, 10/7/08, Klaas-Jan Stol via RT <[EMAIL PROTECTED]> wrote:
> > > Why should this be a PAST::Var node as opposed to
> simply
> > > using a
> > > PAST::Op node with :pirop('getprop')
> and/or
> > > :pirop('setprop') ?
> > >
> > > Pm
> >
> >
> > Why is this different than attribute access?
> >
>
> Maybe, because an attribute access can be more complex, or
> 'nested', if you
> like. For instance, consider this pseudo code:
>
> foo.bar.baz = 1
>
> From the top of my head, I would implement this as a
> PAST::Var, of type
> 'attribute', where the attribute is itself
> represented by a PAST::Var node,
> again of type 'attribute'.
>
> so:
> PAST::Var (foo, PAST::Var(bar, baz))
>
> (not sure if that notation makes any sense, but the first
> operand is the
> object to be indexed, the second is the key).
>
> A property on the other hand is simpler; it's just a
> 'tag' on the object.
> (or maybe it can be accessed in a similar way as
> attributes, the example
> above, ?)
> Just a thought.
>
> kjs
The same can be done with properties. If I understand correctly, the difference
between properties and attributes is just that attributes apply to every
instance of a class and properties can be assigned to every object
independently.
PDD15 says that Python attributes map to Parrot properties. So the same line in
Python (well, Pynie :)
foo.bar.baz = 1
would mean
setprop(getprop(foo, 'bar'), 'baz', 1)
or
PAST::Bind( PAST::Var('baz', PAST::Var('bar', PAST::Var('foo'))), 1)
I think using Bind like this would be much easier than having to figure out
that the lvalue is a property access when compiling the assignment statement.
(Or otherwise figuring out to use getprop). This is also similar to the way
keyed operations work. (I mean: foo[0], foo['baz'] )
