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Added
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- ``Matchable`` class is now callable and indexable. Calling is forwarded to the ``match`` method, and indexing forwards to the ``matches`` attribute, if it exists, and raises an error otherwise.
- ``Matchable`` class now has custom coercion to bool: ``False`` if the last match attempt failed, ``True`` otherwise.
Changed
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- Renamed ``enum`` to ``adt`` to avoid confusion.
- Renamed ``ValueMatcher`` to ``Matchable``.
- ``Matchable.match`` now returns the ``Matchable`` instance, which can then be coerced to ``bool``, or indexed directly.