=< a
|%
++ a 5
--
|% makes a core, ++ names an arm (a computation, not stored data), =< reaches an arm out.
-- closes the core.
glossary
=< evaluates its head against its tail as subject.
=<(a b) is =>(b a), and =<(a [a=5]) is 5.
irregular forms:
arm:core is =<(arm core)
|% makes a core: a battery of named arms, each written ++ name.
reach an arm back out with =< or arm:core.
=< a |% ++ a 5 --
is 5.