Support tuple patterns

[chengluyu]

No description provided.

[LPTK]

Excellent, thanks! I only have two main change requests.

First, please add a test that pattern-matches tuples within a function fun foo(tupleGet) = .... Realize your foolishness. Then fix the bug.

Second, please comment out the vast majority of the uses of the :ucs flag. This produces extremely verbose debugging output that's mostly noise and creates so many diff changes. Especially since it prints symbol UIDs (it probably shouldn't). At most, please only keep a few small but representative uses of :ucs, which can be used to check if there is a regression in the UCS logic. Currently there is just so much output noise that any change creates tons of diffs and regressions may as well go unnoticed, which completely defeats the purpose of diff-testing.

[LPTK]

Awesome contribution, thanks!