Pass-by-reference : Could a C#-like approach work in Python?

Mel Wilson mwilson at the-wire.com
Thu Sep 11 23:47:42 CEST 2003


In article <mv_7b.215$o71.11 at news2.central.cox.net>,
"Steve Holden" <sholden at holdenweb.com> wrote:
>"Stephen Horne" <$$$$$$$$$$$$$$$$$@$$$$$$$$$$$$$$$$$$$$.co.uk> wrote...
>> And if in some future version of Python the suggestion I made was
>> implemented, when you see f(x) you will still know that x cannot be
>> rebound - but when you see f(ref x) you will know that x may well be
>> rebound.
>>
>OK, remind me why this is better than
>
>x = Inc(x)
>
>or
>
>x, y = DoubleInc(x, y)

   My poster child here would be the idiom

        number, digit = divmod (number, base)

which is really handy in converting number to a
representation in some given base.  A different function
could simplify this (in a way) to

        digit = refdivmod (ref number, base)

but at the cost of a new function

        def refdivmod (ref a, b): ...

which, for all the duplication and the new keyword is *less*
capable than what we have, since we can use divmod for
everything refdivmod could do .. but not vice versa.

(A bit late, since everybody in the thread already agrees):     Mel.


P.S.
   This seems like another case of a change that simplifies
some particular line of code, while spreading complication
throughout the rest of the language (new keywords, more
complexity hidden behind subroutine calls, non-obvious
namespace handling.)  I haven't been able to articulate this
opinion of mine well enough to expect it to stand up in a
newsgroup.  Gerald Weinberg's _The Psychology of Computer
Programming_ has some remarks on language design that may
help me out eventually.  Yet another discussion of removing
the 'self' parameter from class methods started me off.

MPW




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