[Python-Dev] PEP 362 Third Revision (original) (raw)

R. David Murray rdmurray at bitdance.com
Fri Jun 15 20:46:09 CEST 2012

On Fri, 15 Jun 2012 11:17:09 -0700, Larry Hastings <larry at hastings.org> wrote:

On 06/15/2012 04:32 AM, Nick Coghlan wrote: > Since I don't believe your proposed flag will answer any question that > actually matters in practice, I consider it useless noise that should > be dropped from the proposal.

I can cite a situation where it matters in practice: the implementation of os.fwalk is effectively gated on hasattr(posix, "openat"). I expect to remove openat() in favor of adding a dirfd parameter to open (see issue 14626).

I don't think that justifies adding an attribute to signature, though. As someone pointed out, it isn't part of the function's signature, it is part of the function's function.

Adding a os.have_openat seems more reasonable than adding is_implemented to every signature object. And more useful, as well; it provides a much more specific piece of information.

> Now, what a function could do is set signature to a Signature > subclass that provided an additional "validate()" method, or provided > arbitrary additional information about supported features. That's a > perfectly reasonable option.

What would the validate() function for os.close do?

Why would you need one?

--David

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