An evaluation arrow "⇒ " precedes a list of values to be returned. For example:
F
a b c ⇒ x
indicates that F
is an operator that has three required parameters
(i.e., a, b, and c) and that returns one value (i.e., x).
If more than one value is returned by an operator, the names of the
values are separated by commas, as in:
F
a b c ⇒ x, y, z