How to do a Decorator Here?

[Gregory Piñero]

On 2/20/07, Tim Mitchell <tmitchell at leapfrog3d.com> wrote:
> Hi Greg,
>
> Decorators would work fine if the the class you were working with was
> _yours_ (ie. you wrote it), the problem here is that string.Template is
> someone else's class that you're trying to modify.
>
> Here's how a decorator would work (unfortunately it involves subclassing)
>
> class myTemplate(string.Template):
>     def decorator(func):
>         def preprocess(*args, **kwargs):
>             # do preprocessing here
>             kwargs['var1'] = "greg"
>             # call actual method
>             return func(*args, **kwargs)
>         return preprocess
>
>     @decorator
>     def substitute(self, *args, **kwargs):
>         return string.Template.substitute(self, *args, **kwargs)
>
> alternatively, if you don't mind changing the string.Template class
> itself (and are sure that it's not used anywhere else that doesn't
> require preprocessing) try:
>
> _substitute = string.Template.substitute
> def subs(self, *args, **kwargs):
>     # do preprocessing here
>     kwargs['var1'] = "greg"
>     return _substitute(self, *args, **kwargs)
> string.Template.substitute = subs
>
> Cheers
> Tim
>

Thanks Tim.  that makes sense now.  Turns out my approach was too
complicated anyway.  I think I'm just going to use Cheetah :-)

But at least I know decorators a little better.

-Greg