[Python-Dev] keyword-only arguments (was Re: string slicing and method consistency)

[Thomas Wouters]

On Fri, Apr 20, 2001 at 04:48:06PM -0500, Guido van Rossum wrote:
> [GVW]

> > Turns out that "abbc".replace("b", "x", -1) is "axxc"
> > (i.e. negative arguments are ignored).  I would have
> > expected this to raise a ValueError, if anything.  Is
> > there a reason for this behavior?  Is it worth making
> > replace, split, etc. interpret negative indices in the
> > same way as indexing does?
> 
> Dubious hypergeneralization.  The thing is that this parameter, called
> maxsplit, is not really an index -- it's a count.

Wouldn't it be nice if we could force particular arguments to be used as
keyword arguments only ? :) I remember this coming up a few times on
python-list, but I never quite understood why this isn't done. Syntax
doesn't seem too much of a problem ('def split(s, sep, **, maxsplit=0)'
comes to mind, and a new marker for PyArg_ParseTuple, like "**") and now
that we have warnings and __future__, we could phase it in even for oft-used
things such as string.split().

Even if it's deemed dubious hypergeneralization (look ma, no macro ;) it's
worth writing a PEP about, right ?

-- 
Thomas Wouters <thomas@xs4all.net>

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