[Python-Dev] PEP 362: 4th edition (original) (raw)

Nick Coghlan ncoghlan at gmail.com
Tue Jun 19 03:29:56 CEST 2012

On Tue, Jun 19, 2012 at 7:06 AM, Jim Jewett <jimjjewett at gmail.com> wrote:

Correct; it should be redundant.  Signature.kwargsparameter should be the same object that occurs as the nth element of Signature.parameters.values().  It is just more convenient to retrieve the parameter directly than it is to iterate through a collection inspecting each element for the value of a specific attribute.

I suspect in 3.4 we will add the following additional convenience properties:

Signature.positional -> list[Parameter] List of POSITIONAL_ONLY and KEYWORD_OR_POSITIONAL parameters Signature.var_positional -> None or Parameter Reference to the VAR_POSITIONAL parameter, if any Signature.keyword -> dict{name:Parameter} Mapping of all KEYWORD_ONLY and KEYWORD_OR_POSITIONAL parameters Signature.var_keyword -> None or Parameter Reference to the VAR_KEYWORD parameter, if any

However, I don't think we should add such convenience properties right now. One step at a time.

eq can can an eqfields attribute to see which other attributes matter -- but it makes more sense for that to be (sub-) class property.

Only if you accept the premise that there are other possible parameter binding behaviours beyond the five already defined. Hypergeneralisation is a great way to make an API far more complex than it needs to be.

Cheers, Nick.

-- Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia

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