[Python-Dev] PEP 318 restrictions on elements (original) (raw)

[Python-Dev] PEP 318 - generality of list; restrictions on elements

Moore, Paul Paul.Moore at atosorigin.com
Wed Mar 10 11:52:34 EST 2004

From: Aahz

That still leaves the question for what is allowed within the brackets. AFAICT, the options are

* A single identifier (which must be a callable) * Comma-separated list of identifiers (which must be callables) * Arbitrary expression (which must produce a sequence of callables)

For completeness, and the one which I understood to be the case,

I still prefer not to state "must be callable" and instead note that they will be called. The former leaves open the question of what will happen if the "must" is violated. The latter is entirely clear. It gets called - so it fails just as it would if called in any other context.

BTW, have we agreed on the order in which decorators will be applied?

Possibly not. I've been assuming the equivalence

def f(a,b) [d1, d2, d3]:
    ...

<=>

def f(a,b):
    ...
f = d1(f)
f = d2(f)
f = d3(f)

but I haven't confirmed this against mwh's patch, and you're right that it should be stated explicitly.

Paul.

PS I'm rapidly going off Guido's def f [...] (...) suggestion. As Just pointed out, I dislike even spaces between the function name and the argument list, so decorators there really do grate.

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