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60 lines
1.8 KiB
Python
60 lines
1.8 KiB
Python
import itertools
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class PseudoStr(str):
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pass
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class StrProxy:
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def __init__(self, value):
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self.value = value
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def __str__(self):
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return self.value
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def __bool__(self):
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return bool(self.value)
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class Object:
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def __repr__(self):
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return '<object>'
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def wrapped_arg_combos(*args,
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wrappers=(PseudoStr, StrProxy),
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skip=(lambda w, i, v: not isinstance(v, str)),
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):
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"""Yield every possible combination of wrapped items for the given args.
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Effectively, the wrappers are applied to the args according to the
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powerset of the args indicies. So the result includes the args
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completely unwrapped.
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If "skip" is supplied (default is to skip all non-str values) and
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it returns True for a given arg index/value then that arg will
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remain unwrapped,
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Only unique results are returned. If an arg was skipped for one
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of the combinations then it could end up matching one of the other
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combinations. In that case only one of them will be yielded.
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"""
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if not args:
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return
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indices = list(range(len(args)))
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# The powerset (from recipe in the itertools docs).
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combos = itertools.chain.from_iterable(itertools.combinations(indices, r)
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for r in range(len(indices)+1))
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seen = set()
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for combo in combos:
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for wrap in wrappers:
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indexes = []
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applied = list(args)
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for i in combo:
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arg = args[i]
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if skip and skip(wrap, i, arg):
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continue
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indexes.append(i)
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applied[i] = wrap(arg)
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key = (wrap, tuple(indexes))
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if key not in seen:
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yield tuple(applied)
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seen.add(key)
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