I've found that a lot of the decorator syntax limitations can be worked around with an identity decorator: i = lambda x: x @i(M(b).decorator()) def wrapped_func(): pass kind of ugly, but it works On Thu, Feb 20, 2014 at 1:31 PM, Franck Michea wrote:

Hi there,

Today I hit a limitation of decorator syntax, and I was wondering if maybe this limitation could be removed, or if they could allow more.

The grammar for decorators is[1]:

decorator: '@' dotted_name [ '(' [arglist] ')' ] NEWLINE

But `dotted_name` doesn't allow to write things like the comment put in the snippet attached, or this smaller snippet:

@M(b).decorator() def wrapped_func(): pass

Although it looks possible to me to add this syntax, I was wondering if it had been discussed previously, and if I could see that discussion.

All discussions I found were a lot older, arround the time decorators were designed and the syntax was being choosen. I also read PEP306 and PEP318.

This is not a blocking issue since you can do with a temporary variable, but I was wondering what were your thoughts on this.

Thank you very much,

[1]: http://docs.python.org/3.3/reference/grammar.html

===== Snippet ========== class foo_decorator: def __init__(self): pass

def __call__(self, func): return func

class Foo: def test(self): return foo_decorator()

class Bar: def __init__(self): self._foo = Foo()

def M(val): return val._foo

b = Bar()

# SyntaxError: @M(b).test() m = M(b) @m.test() def func(): print('Hello World!')

func() ========================

-- Franck Michea - EPITA/LSE/GISTRE 2014 _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/

20.02.2014 22:31, Franck Michea wrote:

Today I hit a limitation of decorator syntax, and I was wondering if maybe this limitation could be removed, or if they could allow more.

The grammar for decorators is[1]:

decorator: '@' dotted_name [ '(' [arglist] ')' ] NEWLINE

But `dotted_name` doesn't allow to write things like the comment put in the snippet attached, or this smaller snippet:

@M(b).decorator() def wrapped_func(): pass

Although it looks possible to me to add this syntax, I was wondering if it had been discussed previously, and if I could see that discussion.

All discussions I found were a lot older, arround the time decorators were designed and the syntax was being choosen. I also read PEP306 and PEP318.

This is not a blocking issue since you can do with a temporary variable, but I was wondering what were your thoughts on this.

AFAIR, there was some discussion a year or a few years ago -- unfortunately I don't remember the details (of course it must be in archives of python-ideas (or maybe python-dev?)). As far as I remember, generally, the belief that this restriction is necessary seemed not to be very strong. Cheers. *j

On 21 February 2014 07:55, Jan Kaliszewski wrote:

As far as I remember, generally, the belief that this restriction is necessary seemed not to be very strong.

Yup, but the gains aren't that great, either - it's never irritated anyone enough for them to write up the necessary PEP and implement the Grammar change :) Cheers, Nick. -- Nick Coghlan | ncoghlan@gmail.com | Brisbane, Australia