[Pyrex] C-methods in extension types

[Lenard Lindstrom]

def methods are exposed to Python. cdef methods are callable only 
from within a Pyrex module, but are a faster. The cdef __new__ bug is 
already known. def __new__ is a special method that the Pyrex 
compiler handles differently. Pyrex does't recognize cdef __new__ as 
special.

Lenard Lindstrom
<len-l at telus.net>

On 20 Feb 2006 at 15:56, Helmut Jarausch wrote:

> Hi,
> I'm new to Pyrex and I don't understand the difference
> between a Python method (declared by 'def') and a
> C method (declared by 'cdef')
> 
> My very first example was this little iterator test
> 
> cdef class IT:
> 
>   cdef int From
>   cdef int To
>   cdef int count
>   cdef int Step
>   
>   def __new__(self,From,To,reversed=0):
>     if reversed:
>       self.Step= -1
>       self.From= To+1
>       self.To  = From
>     else:
>       self.Step= 1
>       self.From= From-1
>       self.To  = To
>     
>   
>   def __iter__(self):
>     self.count= self.From
>     return self
>   
>   def __next__(self):
>     if  self.count == self.To :
>       raise StopIteration
> #      return NULL   # signal STopIteration
>     else :
>       self.count= self.count + self.Step
>       return self.count
> 
> which works just fine.
> But when I try e.g.
> 
>   cdef __new__(self,int From,int To,int reversed):
>     if reversed:
>       self.Step= -1
>       self.From= To+1
>       self.To  = From
>     else:
>       self.Step= 1
>       self.From= From-1
>       self.To  = To
> 
> Then pyrexc doesn't cry but compiles invalid code:
> the function which is put into the tp_new slot
> calls the __new__ method with only 3 arguments
> (which gcc doesn't like)
> 
> What am I missing?
> 
> Many thanks for a hint,
> 
> Helmut Jarausch
> 
> Lehrstuhl fuer Numerische Mathematik
> RWTH - Aachen University
> D 52056 Aachen, Germany
> 
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