[Python-Dev] Decorator syntax

[Erik Bray]

On Wed, Sep 2, 2009 at 10:35 AM, James Y Knight<foom at fuhm.net> wrote:
> On Sep 2, 2009, at 6:15 AM, Rob Cliffe wrote:
>
>> So - the syntax restriction seems not only inconsistent, but pointless; it
>> doesn't forbid anything, but merely means we have to do it in a slightly
>> convoluted (unPythonesque) way.  So please, Guido, will you reconsider?
>
> Indeed, it's a silly inconsistent restriction. When it was first added I too
> suggested that any expression be allowed after the @, rather than having a
> uniquely special restricted syntax. I argued from consistency of grammar
> standpoint. But Guido was not persuaded. Good luck to you. :)
>
> Here's some of the more relevant messages from the thread back when the
> @decorator feature was first introduced:
> http://mail.python.org/pipermail/python-dev/2004-August/046654.html
> http://mail.python.org/pipermail/python-dev/2004-August/046659.html
> http://mail.python.org/pipermail/python-dev/2004-August/046675.html
> http://mail.python.org/pipermail/python-dev/2004-August/046711.html
> http://mail.python.org/pipermail/python-dev/2004-August/046741.html
> http://mail.python.org/pipermail/python-dev/2004-August/046753.html
> http://mail.python.org/pipermail/python-dev/2004-August/046818.html

I think Guido may have a point about not allowing any arbitrary
expression.  But I do think that if it allows calls, it should also at
least support the itemgetter syntax, for which there seems to be a
demonstrable use case.  But that's just adding on another special
case, so it might be simpler to allow arbitrary expressions.