[Python-Dev] PEP 362 Third Revision (original) (raw)

Terry Reedy tjreedy at udel.edu
Thu Jun 14 20:02:13 CEST 2012

On 6/14/2012 1:10 PM, Brett Cannon wrote:

On Thu, Jun 14, 2012 at 12:39 PM, Yury Selivanov <yselivanov.ml at gmail.com <mailto:yselivanov.ml at gmail.com>> wrote: On 2012-06-14, at 12:32 PM, Benjamin Peterson wrote: > 2012/6/14 Yury Selivanov <yselivanov.ml at gmail.com_ _<mailto:yselivanov.ml at gmail.com>>: >> On 2012-06-14, at 11:24 AM, Brett Cannon wrote: >>> On Thu, Jun 14, 2012 at 9:50 AM, Yury Selivanov <yselivanov.ml at gmail.com <mailto:yselivanov.ml at gmail.com>> wrote: >>> >>> [SNIP] >>> >>> Let's consider replacement of 'Parameter.is*' set of attributes with >>> a single 'Parameter.kind' attribute, which will have the following >>> possible values: 'positional', 'vararg', 'keyword-only', 'varkwarg'. >>> >>> (I think 'positional' is more intuitive than 'index'?) >>> >>> >>> +1 if this change is made. >> >> How about adding 'kind' and keeping 'is*' attributes, >> but making them read-only dynamic properties, i.e.: >> >> class Parameter: >> ... >> >> @property >> def isvararg(self): >> return self.kind == 'vararg' >> >> ... >> >> ? > > Seems a bit bloatly to me. (One way to do it.) Yes, but on the other hand it solves "strings are error prone" argument, keeps all 'is*' attributes in sync, and makes them read-only. 'kind' property may do validation on set, to diminish mistakes probability even further. I agree with Benjamin, it goes against TOOWTDI without enough of a justification to break the rule. Just make the strings constants on the Parameter class and you solve the lack of enum issue.

My opinion: I don't like the multiple radio-button attributes either. It is one attribute with multiple values. We use constants elsewhere. In the absence of an enum type that maps ints to a string, the constants should be strings for display and printing.

-- Terry Jan Reedy

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