On Mon, Dec 29, 2008 at 8:55 PM, Paolo Giarrusso <p.giarrusso@gmail.com> wrote:
Atatched is a small patch for the annotator that makes it treat None and NotImplemented alike. This is all that is needed for most cases as all NotImplemented are typically removed by the optimisations performed by the annotator.
That can be made to work, but if such a method returns None you get completely different semantics (trying again with something else) from CPython (which will maybe return a failure, or return None for the result of such an operation), so you have to restrict the allowed
No, the patch do distinguish between None and NotImplemented. What I mean is that NotImplemented is treated in a similar manner as to how None is treated. The following crazy construction do compile and generate the same result as in cpython ('OK', 'String', 'None', 'None'): class mystr: def __init__(self,s): self.s=s def __str__(self): return self.s def __add__(self,other): if isinstance(other,mystr): return NotImplemented s=self.s+other if s=='None': return None else: return s __add__._annspecialcase_ = 'specialize:argtype(1)' def __radd__(self,other): return str(other)+self.s __radd__._annspecialcase_ = 'specialize:argtype(1)' def dotst_nonestr(): s1=mystr('No')+'ne' if s1 is None: s1='OK' s2=mystr('Str')+'ing' s3=mystr('No')+mystr('ne') s4='No'+mystr('ne') return (s1,s2,s3,s4) -- Håkan Ardö