a gate body can be any expression, a conditional included.
=/ pins a named value (a face) into the subject for the lines below it.
name=value optionally declares the type.
=/(a 3 (add a a)) is 6.
|= makes a gate: a function with one named sample, then a body.
the body runs with the sample bound.
call the gate to run it.
(|=(a=@ (add a 1)) 4) is 5.
$= wraps a mold with a face, naming the value it produces.
$=(x @) is the mold x=@.
?: is if-then-else: it picks its first branch when the test is yes, the second when no.
?:((gth 3 5) 10 20) is 20.
%: calls a gate with several arguments, gathering them into one sample.
%:(add 2 3) is 5.
irregular forms:
(gate a b c) is %:(gate a b c)
gth asks whether the first atom is strictly greater than the second.
(gth 5 3) is %.y.