Since the _real_ issue seems to be wanting an easy way to construct an OrderedDict, I thought the earlier discussion about frozenset literals might be relevant. On Wed, Feb 13, 2013, at 17:02, random832@fastmail.us wrote:
On Sat, Feb 2, 2013, at 9:20, Steven D'Aprano wrote:
Unfortunately the proposal to use f{ ... } for frozen sets cannot work within the constraints of Python's lexer:
http://mail.python.org/pipermail/python-3000/2008-January/011838.html
Unfortunately we're running out of useful, easy to enter symbols for literals. Until such time (Python4000 perhaps, or more likely Python5000) as we can use a rich set of Unicode literals, I don't think there is any clear way to have a frozenset literal.
I was going to post about not being sure what the objection is (if it's multiple tokens, let it be multiple tokens - the contents are multiple tokens anyway - and saying it would block a future syntax extension doesn't seem like a reasonable objection to a proposed syntax extension), but I had a new idea so I'll post that instead:
{ as frozenset { ... } }
The sequence "{ as" can't occur (to my knowledge) anywhere now. So, the thing after it is a keyword in that context (and only that context, otherwise "frozenset" remains an identifier naming an ordinary builtin) and specifies what kind of literal the following sequence is. You could also extend it to alternate forms for some other builtin types - for example { as bytes [1, 2, 3, 4, 5] } instead of b"\x1\x2\x3\x4\x5". Or... { as set { } } _______________________________________________ Python-ideas mailing list Python-ideas@python.org http://mail.python.org/mailman/listinfo/python-ideas
-- Random832