PJ Eby <pje <at> telecommunity.com> writes:
I notice that distlib appears to support chaining of comparisons, but the PEP does not. ISTM that there is no sane use case for chaining, given the nature of comparisons that are allowed. (That is, if you perform one equality or contains comparison between two values, then you know how the next comparison would turn out.)
If chained comparisons are disallowed in the PEP, then distlib probably shouldn't be allowing them either, to prevent interop issues w/tools that only support what's in the PEP.
Sorry if I'm being dense, but can you confirm that what you mean by "chaining" is something like "a < b <= c"? Things can be tightened up once PEP 426 is finalised. At the moment, distlib allows expressions like "python_version >= '2.6'" or "python_version < '3.5'" which are also not mentioned in the PEP. I don't recall seeing any discussion around why allowing inequalities might be a bad idea, but perhaps someone can point me to it? Perhaps it should be mentioned in the PEP. Regards, Vinay Sajip