Re: Pre-commit hooks

speed wise, this is better: hasattr is implemented as getattr + try 
except. i would do it even:
  f = getattr(instance, "_pre_insert", None)
  if f: f()
Thus the func name is spelled only once - avoids stupid mistakes.

On Thursday 15 May 2008 17:36:52 Roger Demetrescu wrote:
> On 5/15/08, Yannick Gingras <ygingras <at> ygingras.net> wrote:
> > Michael Bayer <mike_mp <at> zzzcomputing.com> writes:
> > > easy enough to build yourself a generic MapperExtension that
> > > scans incoming objects for a "_pre_commit()" method.
> >
> > Yeah indeed.  I used this:
> >
> > ------------------------------
> > class HookExtension(MapperExtension):
> >    """ Extention to add pre-commit hooks.
> >
> >    Hooks will be called in Mapped classes if they define any of
> > these methods:
> >      * _pre_insert()
> >      * _pre_delete()
> >      * _pre_update()
> >    """
> >    def before_insert(self, mapper, connection, instance):
> >        if getattr(instance, "_pre_insert", None):
> >            instance._pre_insert()
> >        return EXT_CONTINUE
>
> [cut]
>
> Any reason for not using hasattr  ? Like...
>
>     def before_insert(self, mapper, connection, instance):
>         if hasattr(instance, "_pre_insert"):
>             instance._pre_insert()
>         return EXT_CONTINUE
>
>
> Cheers,
>
> Roger
>
> 

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