[Distutils] FINAL DRAFT: Dependency specifier PEP

Nathaniel Smith njs at pobox.com
Mon Nov 16 20:30:17 EST 2015

On Nov 16, 2015 12:46 PM, "Robert Collins" <robertc at robertcollins.net>
>     marker        = wsp* marker_expr ( wsp* ('and' | 'or') wsp*

I guess technically the spec doesn't say either way what the precedence of
"and" versus "or" should be; it just parses unparenthesised sequences to a
flat ast and in principle the (unspecified) ast evaluator could apply
different precedences. The way the grammar's written though seems to
suggest that they're equal precedence with some unspecified associativity,
which is different from python where "and" is more tightly binding than
"or" (and associativity doesn't matter because each operator is associative
in isolation). Maybe this is implied here too via the language about how
this is intended to be a python subset, but it would be good to clarify
what the evaluation semantics should be.

Other comments:

The whitespace handling looks correct to me now :-)

I didn't check that the two copies of the grammar are identical (and I only
looked at the top version, not the bottom version). Hopefully someone did?
It'll be a headache if we discover later that there's skew between them,
and no guidance on which is normative.

Otherwise looks good to me.

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