Sum of a left (errorneous) or correct (right) value
List of Import References :
See BOOL
See DENOTATION
SIGNATURE Either[a,b]
$Date: 2012-10-02 14:17:54 +0200 (Tue, 02 Oct 2012) $ ($Revision: 838 $)
SORT a b
Either a left or right value
TYPE either == left(left:a)
right(right:b)
Either is similar to the Union2 structure with
more intuitive names.
next node: Option,
prev node: Dyn,
up to node: Subsystem UnionLike