Terry J. Reedy <[email protected]> added the comment:
I forget about this defaultdict behavior: "this value is inserted in the
dictionary for the key, and returned." Reason: when default_factory returns a
mutable, d[key] must return the same possibly mutated object with each call. I
agree that defaultdict is not the right replacement.
We need to pass to str.translate a dict that can be used by subscripting,
newchar = d[char]. So partial(non-defaults.get, default_value) will not work.
Instead, we need a __getitem__ that returns the same.
In msg312444 I suggested simplifying STPM (including the name) because it has
unneeded complexity. Remove the buggy .get override. Combine the _get stuff
in __init__ (also removed) with current __getitem__ and simplify and we get
what we actually need (untested, at yet).
def __getitem__
return self._non_defaults.get(self._default_value)
Actually, we could hard-code the default value as 'X' as we never need anything
else.
How about ParseMap for the name?
----------
stage: patch review -> needs patch
title: IDLE: pyparse - replace StringTranslatePseudoMapping with defaultdict ->
IDLE: pyparse - simplify StringTranslatePseudoMapping
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<https://bugs.python.org/issue32940>
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