Tuple patterns

Atuple patternhas the form(p1, p2, … pn)wherep1throughpnare patterns. The pattern matches if the scrutinee is a tuple of the samearityas the pattern andp1throughpnmatch against the elements of the tuple. The pattern(p)is the same as the patternp,and the pattern()matches the literal value()of the trivial type {()} (both pronounced “unit”).

For example, this expression evaluates to `4`:

(a, _, c) = (1, 2, 3)
a Nat.+ c
⧨
4