butlast : (* list -> * list)

SYNOPSIS
Computes the sub-list of a list consisting of all but the last element.

DESCRIBE
butlast [x1;...;xn] returns [x1;...;x(n-1)].

FAILURE
Fails if the list is empty.

SEEALSO  last,   hd,   tl,   el,   null

HOL  Kananaskis 0