[Python-Dev] Proposed tweaks to functools.wraps (original) (raw)

Nick Coghlan ncoghlan at gmail.com
Wed Aug 11 06:43:40 CEST 2010

On Wed, Aug 11, 2010 at 1:22 PM, Steve Holden <steve at holdenweb.com> wrote:

One of the things that's slightly irking about the decorator syntax is that a decorator is always called with exactly one argument, and that if you want to write a parameterized decorator you therefore end up writing a function that returns a function that returns a function.

I've scratched my head about how partials (or indeed anything else) could be used to make the extra level of indirection necessary, but haven' come up with anything that even I could regard as acceptable. But I can't escape this feeling that there must be a way.

Making the parameterised decorator a callable rather than a function can sometimes help, provided there are only a few parameters actually needed in the wrapper function.

Making parameterised decorators easier to parse mentally was pointed out [1] as a possible benefit of pursuing PEP 3150 (statement local namespaces). That PEP as a whole is still sitting in "not enough practical benefit to justify the pain" territory though.

Cheers, Nick.

[1] http://mail.python.org/pipermail/python-ideas/2010-July/007691.html

-- Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia

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