[Python-Dev] Proposing PEP 345 : Metadata for Python Software Packages 1.2 (original) (raw)

Lennart Regebro regebro at gmail.com
Mon Dec 28 11:21:05 CET 2009

Another penny dropped when it comes to version specs.

Should 2.5 mean 2.5.0 only, or 2.5.*. Well... why would you ever need to specify 2.5.0 only. That's a nonsense specification.

"My project requires Python 2.5.0, but doesn't work with 2.5.1". Huh!? Well, then fix it, goofball. :)

2.5 can mean 2.5.* without any problems. And 3 should mean 3...

New suggested spec:

versionrequirements ::= 'Requires-Python: ' specificationlist specificationlist ::= specification (; specification)* specification ::= version | "[" [version] ":" [version] "]" version ::= lc_number ["." lc_number [ "." lc_number ] ]

With examples being:

Requires-Python: [2.5.2:3]; [3.1:]

Or on several rows:

Requires-Python: [2.5.2:3];
                [3.1.2];
                [3.2:]

Meaning 2.5.2 or later, but not Python 3. or Python 3.1.2. or Python 3.2 or later.

Or if slicing syntax is not wanted:

versionrequirements ::= 'Requires-Python: ' specificationlist specificationlist ::= specification (; specification)* specification ::= version | minimum | maximum | miniumum " " maximum minimum ::= ('>' | '>=') version maximum ::= ('<' | '<=') version version ::= lc_number ["." lc_number [ "." lc_number ] ]

That would mean something like the following:

Requires-Python: >= 2.5.2 < 3; >= 3.1

or more clearer if it's split up in lines:

Requires-Python: >= 2.5.2 < 3;
                >= 3.1

The following would be illegal:

Requires-Python: >= 2.5.2 > 3
Requires-Python: <= 2.5.2 < 3
Requires-Python: <= 2.5.2 < 3 > 3.1

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