lp.Reduction.inames_set must return frozenset

[kaushikcfd]

Returning mutable objects from memoized routines is dangerous.

(py314_env) kaushikggg@line:~/temp$ cat tmp.py 
import loopy as lp


def _get_iname_set(redn: lp.Reduction) -> frozenset[str]:
    iname_frozenset = frozenset(redn.inames_set)
    redn.inames_set.add("i am introducing a bug.")
    return iname_frozenset


def _get_sorted_inames(redn: lp.Reduction) -> tuple[str, ...]:
    return tuple(sorted(redn.inames_set))


if __name__ == "__main__":
    from loopy.symbolic import parse
    expr = parse("sum(i, i**2)")
    print(_get_iname_set(expr))
    print(_get_sorted_inames(expr))

(py314_env) kaushikggg@line:~/temp$ python tmp.py 
frozenset({'i'})
('i', 'i am introducing a bug.')