[Python-ideas] frozenset literals

[Hua Lu]

Hey all, I have a simple hack around this problem for the time being.
It involves adding a parameter to ast.literal_eval. See this diff:

$ diff ast.py.bak ast.py
38c38
< def literal_eval(node_or_string):
---
> def literal_eval(node_or_string, use_frozensets=False):
49a50
>     set_t = frozenset if use_frozensets else set
60c61
<             return set(map(_convert, node.elts))
---
>             return set_t(map(_convert, node.elts))

Use is as follows:
>>> import ast
>>> ast.literal_eval("{1,2,3}")
{1, 2, 3}
>>> ast.literal_eval("{1,2,3}", use_frozensets=True)
frozenset({1, 2, 3})
>>> ast.literal_eval("{{1,2,3}: 'foo'}", use_frozensets=True)
{frozenset({1, 2, 3}): 'foo'}

Regards,
Alan