Re: [Cython] In Py=2.6, kwargs can be general mappings
On Dec 22, 2009, at 6:43 AM, Stefan Behnel wrote: Lisandro Dalcín, 22.12.2009 15:33: The support for new feature in core CPython is at Python/ceval.c, function ext_do_call(). Ah, I get it. So the problem is that this is done as part of the / call/ (and basically by the interpreter), for which Cython has its own code. I think that's worth a trac ticket, then, although I consider it a rather minor feature. Yep, we should support this (though I agree that it's minor). http://trac.cython.org/cython_trac/ticket/470 - Robert ___ Cython-dev mailing list Cython-dev@codespeak.net http://codespeak.net/mailman/listinfo/cython-dev
[Cython] In Py=2.6, kwargs can be general mappings
While testing type inference in mpi4py, I noticed that code like the
one below is failing in the last line. It seems that in Py=2.6,
Python makes a coercion on kw and builds an actual dict instance
before calling.
class Foo:
def view(self, **kw):
print (kw)
for k in kw.keys():
print (k)
Foo().view(a=0, b=1, c=2)
class MyDict(object):
def __getitem__(self, k):
assert k == 'a'
return 7
def keys(self):
return ['a']
Foo().view(**MyDict()) # -- Here is the issue
Running on Py=2.6, the code above gives:
{'a': 0, 'c': 2, 'b': 1}
a
c
b
{'a': 7}
a
so that makes me think that at some point Python is building a tmp
dict out of MyDict instance.
--
Lisandro Dalcín
---
Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)
Instituto de Desarrollo Tecnológico para la Industria Química (INTEC)
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
PTLC - Güemes 3450, (3000) Santa Fe, Argentina
Tel/Fax: +54-(0)342-451.1594
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Re: [Cython] In Py=2.6, kwargs can be general mappings
On Tue, Dec 22, 2009 at 10:58 AM, Stefan Behnel stefan...@behnel.de wrote:
Lisandro Dalcín, 22.12.2009 14:47:
While testing type inference in mpi4py, I noticed that code like the
one below is failing in the last line. It seems that in Py=2.6,
Python makes a coercion on kw and builds an actual dict instance
before calling.
class Foo:
def view(self, **kw):
print (kw)
for k in kw.keys():
print (k)
Foo().view(a=0, b=1, c=2)
class MyDict(object):
def __getitem__(self, k):
assert k == 'a'
return 7
def keys(self):
return ['a']
Foo().view(**MyDict()) # -- Here is the issue
Running on Py=2.6, the code above gives:
{'a': 0, 'c': 2, 'b': 1}
a
c
b
{'a': 7}
a
so that makes me think that at some point Python is building a tmp
dict out of MyDict instance.
Interesting. So, what's your point? It didn't work before and it works now
by passing in a real dict. Does this impact Cython in any way?
Sorry, I was not clear enough. My point is that the line below fails:
Foo().view(**MyDict())
see yourself:
In [1]: import pyximport; pyximport.install()
In [2]: import kargs
{'a': 0, 'c': 2, 'b': 1}
a
c
b
---
ImportError Traceback (most recent call last)
/u/dalcinl/tmp/ipython console in module()
...
--- 18 Foo().view(**MyDict())
ImportError: Building module failed: ['TypeError: keyword list must be
a dictionary\n']
So, in short Cython does not follow Python (=2.6, including 3.x).
Cython should generate some extra code to support this new Python
feature:
tmp =MyDict()
if not isinstace(tmp, dict):
tmp = dict(tmp)
Foo().view(**tmp)
PS: The support for new feature in core CPython is at Python/ceval.c,
function ext_do_call(). This feature was tracked here:
http://bugs.python.org/issue1686487
--
Lisandro Dalcín
---
Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)
Instituto de Desarrollo Tecnológico para la Industria Química (INTEC)
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
PTLC - Güemes 3450, (3000) Santa Fe, Argentina
Tel/Fax: +54-(0)342-451.1594
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Re: [Cython] In Py=2.6, kwargs can be general mappings
Lisandro Dalcín, 22.12.2009 15:33: The support for new feature in core CPython is at Python/ceval.c, function ext_do_call(). Ah, I get it. So the problem is that this is done as part of the /call/ (and basically by the interpreter), for which Cython has its own code. I think that's worth a trac ticket, then, although I consider it a rather minor feature. Stefan ___ Cython-dev mailing list Cython-dev@codespeak.net http://codespeak.net/mailman/listinfo/cython-dev
