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Unification of Methods and Functions

Terry Reedy tjreedy at udel.edu
Tue May 11 14:46:12 EDT 2004 
"Antoon Pardon" <apardon at forel.vub.ac.be> wrote in message
news:slrnca1d94.1i9.apardon at trout.vub.ac.be...
> I don't see how this contradicts what I want to say. In both case you
have
> something of the form
>
>   obj = cls()
>
> And in both obj.method() is equivallent to cls.method(obj)

I believe Timothy's point was that inst.meth() is more general than any
specific clas.meth(inst) whenever there is more than one possible meaning
of 'clas'.  In the following snippet, one can only replace 'animal.speak',
without changing semantics, with 'animal.__class__.speak(animal)' and not
with any specific versioon of clas.speak(animal).  If something cannot be
substituted without changing meaning, in a particular context, then, in
that context, it literally does not mean the same thing.

class mammal:
  def speak(self): print 'umf'

class dog(mammal):
  def speak(self): print 'arf'

class cat(mammal):
  def speak(self): print 'meow'

for animal in [mammal(), dog(), cat()]: animal.speak()
>>>
umf
arf
meow
>>>

Terry J. Reedy
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