NAME
    segment - segment from and to specified elements of a list

SYNOPSIS
    segment(x, y, z)

TYPES
    x		list
    y, z	int

    return	list

DESCRIPTION
    For 0 <= y < size(x) and 0 <= z < size(x), segment(x, y, z)
    returns a list for which the values of the elements are those
    of the segment of x from x[[y]] to x[[z]].	If y < z, the
    new list is in the same order as x; if y > z, the order is
    reversed.

    If y < z, x == join(head(x,y), segment(x,y,z), tail(x, size(x) - z - 1)).

EXAMPLE
    > A = list(2, 3, 5, 7, 11)
    > segment(A, 1, 3)

    list (3 members, 3 nonzero):
	  [[0]] = 3
	  [[1]] = 5
	  [[2]] = 7

    > segment(A, 3, 1)

    list (3 members, 3 nonzero):
	  [[0]] = 7
	  [[1]] = 5
	  [[2]] = 3

LIMITS
    0 <= y < size(x)
    0 <= z < size(x)

LIBRARY
    none

SEE ALSO
    head, tail