[Cython] CF based type inference

[Robert Bradshaw]

On Fri, May 11, 2012 at 8:56 AM, Stefan Behnel <stefan_ml at behnel.de> wrote:
> Robert Bradshaw, 11.05.2012 17:48:
>> On Tue, May 8, 2012 at 11:22 PM, Stefan Behnel <stefan_ml at behnel.de> wrote:
>>> Robert Bradshaw, 09.05.2012 00:12:
>>>> On Tue, May 8, 2012 at 6:47 AM, Vitja Makarov wrote:
>>>>> 2012/5/8 Stefan Behnel:
>>>>>> Vitja has rebased the type inference on the control flow, so I wonder if
>>>>>> this will enable us to properly infer this:
>>>>>>
>>>>>>  def partial_validity():
>>>>>>    """
>>>>>>    >>> partial_validity()
>>>>>>    ('Python object', 'double', 'str object')
>>>>>>    """
>>>>>>    a = 1.0
>>>>>>    b = a + 2   # definitely double
>>>>>>    a = 'test'
>>>>>>    c = a + 'toast'  # definitely str
>>>>>>    return typeof(a), typeof(b), typeof(c)
>>>>>>
>>>>>> I think, what is mainly needed for this is that a NameNode with an
>>>>>> undeclared type should not report its own entry as dependency but that of
>>>>>> its own cf_assignments. Would this work?
>>>>>>
>>>>>> (Haven't got the time to try it out right now, so I'm dumping it here.)
>>>>>>
>>>>>
>>>>> Yeah, that might work. The other way to go is to split entries:
>>>>>
>>>>>  def partial_validity():
>>>>>   """
>>>>>   >>> partial_validity()
>>>>>   ('str object', 'double', 'str object')
>>>>>   """
>>>>>   a_1 = 1.0
>>>>>   b = a_1 + 2   # definitely double
>>>>>   a_2 = 'test'
>>>>>   c = a_2 + 'toast'  # definitely str
>>>>>   return typeof(a_2), typeof(b), typeof(c)
>>>>>
>>>>> And this should work better because it allows to infer a_1 as a double
>>>>> and a_2 as a string.
>>>>
>>>> This already works, right?
>>>
>>> It would work if it was implemented. *wink*
>>
>> Well, we don't infer str
>
> Yes we do, there are even some optimisations for str. It's well defined for
> both Py2 and Py3, just not the same on both, so the final code to use for
> them is C compile time dependent.
>
> I meant to say that entry splitting isn't implemented.

Yeah, that isn't implemented yet.

- Robert