[issue1745] Backport of PEP 3102 "keyword-only arguments" to 2.6

[Robin Stocker]

New submission from Robin Stocker:

The attached patch ports the implementation of keyword-only arguments
from revision 52491 back to trunk.

This is the first time I've worked on the C internals, so here are some
notes:

- test_collections is the only test which fails, because it tries to
call a function with more than 255 arguments, which results in a
SyntaxError because of the following added code in Python/ast.c. What
should be done about it?

    if (nposargs + nkwonlyargs > 255) {
        ast_error(n, "more than 255 arguments");
        return NULL;
    }

- The patch only adds what's in revision 52491. There is at least one
more change involving keyword-only arguments, for example issue1573. Are
there others? Should they be included in this patch or in a separate one?

- There are some changes which were generated, like Python/Python-ast.c
(which needs to be checked in separately).

- Is there documentation which needs to be updated?

----------
components: Interpreter Core
files: backport-keyword-only-arguments.patch
messages: 59391
nosy: robin.stocker
severity: normal
status: open
title: Backport of PEP 3102 "keyword-only arguments" to 2.6
type: behavior
versions: Python 2.6
Added file: http://bugs.python.org/file9078/backport-keyword-only-arguments.patch

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