[Python-Dev] PEP 318 - posting draft (original) (raw)

Delaney, Timothy C (Timothy) tdelaney at avaya.com
Sun Mar 28 18:37:28 EST 2004

From: Guido van Rossum

OTOH, for long argument lists, the "preferred" form has the reverse problem: the decorators are separated from the function name by the long argument list. The question then becomes, what is more likely: long argument lists or long lists of decorators? I know that (at least in certain code bases :) long argument lists are common. Will long lists of decorators ever become popular? I think we'll have to look for languages that already have decorators (especially C#) for what the future might give. I'll be talking to folks at PyCon about this.

I've come back to this, because I've finally solidified one reason why I think the form:

def func (args) [decorators]:

is my preference. I've seen this expressed obliquely by other people, but not explicitly, so I want to add it as an explicit argument now.

The first part of the definition:

def func (args)

is required for every function definition. However, the [decorators] part is optional. I think this distinction is very important - we can guarantee that if we use the format:

def func (args) [decorators]:

then every function signature looks the same - name; arguments; optional decorators. OTOH, if we go with:

def func [decorators] (args):

then function signatures look different in different places.

A side issue is that due to the conventions used in command lines and the python documentation, the first form actually reads like "def name arguments optional decorators" - c.f. range([start,] stop[, step]) - which may or may not be a good thing. Would it contribute to people thinking the [] weren't part of the decorator list, but merely a documentation thing?

Tim Delaney

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