the gather
;: turns a two-argument gate into an n-ary one, folding it across all the arguments.
;:
;:(add 1 2 3) is 6.
;:(add 1 2 3)
6
irregular forms:
:(gate a b c) is ;:(gate a b c)
:(gate a b c)
;:(gate a b c)
add sums two atoms.
add
(add 2 3) is 5.
(add 2 3)
5