[Python-ideas] pattern matching proof-of-concept

[Michael Selik]

My original dict unpacking proposal was very short and lacked a motivating
usage. Toy examples made my proposal look unnecessarily verbose and
suggested obvious alternatives with easy current syntax.

Nested/recursive unpacking is much more troublesome, especially when
combined with name-binding. I wrote an example to compare my proposal with
current syntax.

Example usage.
https://github.com/selik/destructure/blob/master/examples/fips.py

Implementation.
https://github.com/selik/destructure/blob/master/destructure.py

The design of my module I'm least happy with is the name-binding. I
extended a SimpleNamespace to create an Erlang-style distinction between
bound and unbound names. Though the API is a bit awkward, now that the
module is built, I'm less enthusiastic about introducing new syntax. Funny
how that works.

I haven't yet decided how to add post-binding guards to the cases.
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