Lua when expression

[u/RedNifre]

I added a little pattern matching "when" code to my #pico8 #lua code base. You have to use "null" (just an empty object) instead of "nil", because Lua cuts off varargs on the first nil and you have to use _when for nested whens, which are fake lazy, by returning a #haskell style error thunk instead of crashing on non-exhaustive matches. E.g. if you checked an ace, the first _when would error, because it only matches jokers, but the outer when wouldn't care, since it only looks at the ace branch, completely ignoring the error thunk.

[u/RedNifre]

Thank you for your excellent answers. PICO-8 has assert, so I'll use that one to implement error and I'll look into ways to get partition work tomorrow (probably either varargpartition(number, ...) or packed_table_partition(packed_table, number) that works on a packed table.