.he 'LENGTH''Page %'
.fo 'Steven Hardy''January 78'
LENGTH
Given a structure, this function returns the number of components
it contains, for example:
 	: LENGTH("ABCD") =>
 	** 4
 	: LENGTH({A B C D}) =>
 	** 4
 	: LENGTH('ABCD') =>
 	** 4
 	: LENGTH([A B C D]) =>
 	** 4
.br
Notice that LENGTH 'cheats' slightly if given a list in that
since lists are made up of a chain of two element structures
(with components accessed with HD and TL) it ought really
to return 2 given any list. This would not be useful so in this
event LENGTH computes the number of elements in the list.
