[Python-ideas] Keyword only argument on function call

Kyle Lahnakoski klahnakoski at mozilla.com
Sat Sep 8 13:33:22 EDT 2018

I agree that this is a familiar pattern, but I long since forgot the
specifics of the domain it happens in.  I borrowed your code, and added
filename tracking to see what source files had high
`could_have_been_a_matched_kwarg`.  Here is the top one:


The argument-name-matches-the-local-variable-name pattern does appear to
happen in many test files. I assume programmers are more agnostic about
variable names in a test because they have limited impact on the rest of
the program; matching the argument names makes sense.

There are plenty of non-test files that can use this pattern, here are
two intense ones:

(212 call parameters match)
(69 call parameters match)

Opening these in an IDE, and looking at the function definitions, there
is a good chance you find a call where the local variable and argument
names match.  It is interesting to see this match, but I not sure how I
feel about it.  For example, the options.py has a lot of small methods
that deal with (request, obj) pairs: eg 
`has_view_or_change_permission(self, request, obj=None)`  Does that mean
there should be a namedtuple("request_on_object", ["request", "obj"]) to
"simplify" all these calls?  There are also many methods that accept a
single `request` argument; but I doubt they would benefit from the new

On 2018-09-06 06:15, Anders Hovmöller wrote:
> I have a working implementation for a new syntax which would make using keyword arguments a lot nicer. Wouldn't it be awesome if instead of:
> 	foo(a=a, b=b, c=c, d=3, e=e)
> we could just write:
> 	foo(*, a, b, c, d=3, e)

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