=/ a=(unit @) (some 5)
?=(^ a)
?= matches a value to a shape — here ^, a cell, so it is yes on a non-empty unit: the opposite of ?~.
glossary
=/ 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.
unit is the maybe type: either ~ or [~ value].
(unit @) holds an atom or nothing.
%: 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)
some wraps a value in a unit - [~ value].
(some 5) is [~ 5].
?= tests whether a value matches a shape, giving a loobean.
?=(^ [1 2]) is %.y.