[Distutils] PEP-426 environment markers [was: Re: Support for condition to include or exclude a buildout sections based on a Python expression]

[Daniel Holth]

Yes even on 64 bit Windows
On Jan 30, 2013 12:18 PM, "Leonardo Rochael Almeida" <leorochael at gmail.com>
wrote:

> Even on 64 bit windows?
>
> On Wed, Jan 30, 2013 at 2:37 PM, Daniel Holth <dholth at gmail.com> wrote:
> > One more thing: sys.platform != 'win32' is how you write "not windows"
> >
> >
> > On Wed, Jan 30, 2013 at 10:13 AM, Daniel Holth <dholth at gmail.com> wrote:
> >>
> >> On Wed, Jan 30, 2013 at 9:58 AM, Jim Fulton <jim at zope.com> wrote:
> >>>
> >>> On Wed, Jan 30, 2013 at 9:46 AM, Daniel Holth <dholth at gmail.com>
> wrote:
> >>> > My markerlib implements the PEP.
> https://bitbucket.org/dholth/markerlib
> >>> >
> >>> > The parsing is simpler than you might expect. There is no monkey
> >>> > patching.
> >>> >
> >>> > It is a (non-API) part of distribute since about last August.
> >>>
> >>> But we're not implementing the PEP. The PEP is only tangentially
> >>> related to this use case.  I'd be happy to be PEP informed, but not if
> >>> it makes things awkward.
> >>>
> >>> It's much easier to say "these are python expressions with the
> >>> following variables available" than to say "you can use the
> >>> expressions described in PEP 426 plus additional variables", where,
> >>> BTW, you can't say ``not windows``, which is probably one of the 2
> >>> most common expressions you'd want to use.  Note that many or most
> >>> buildout users would have no reason to be familiar with the PEP.
> >>>
> >>> This isn't a criticism of the PEP. The PEP was developed for
> >>> some use case that's different than this one.  Well, I'm guessing
> >>> because the PEP doesn't actually state the problems it's addressing.
> >>
> >>
> >> The PEP is a little weird, especially the inconsistent _ versus .
> >> separators. Markerlib is a little more permissive than the spec.
> >>
> >> Variable names can contain . when you are using eval().
> >>
> >> The ast module is really cool. It can be used to implement powerful
> >> limited evaluation with very little code (but only in Python 2.6+).
> >>
> >> Happy building.
> >>
> >> Daniel Holth
> >
> >
> >
> > _______________________________________________
> > Distutils-SIG maillist  -  Distutils-SIG at python.org
> > http://mail.python.org/mailman/listinfo/distutils-sig
> >
>
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