singleton_of_list : 'a list -> 'a
STRUCTURE
Lib
SYNOPSIS
Turns a single-element list into a singleton.
DESCRIPTION
singleton_of_list [x] returns x.
FAILURE
Fails if applied to a list that is not of length 1.
SEEALSO
pair_of_list, triple_of_list, quadruple_of_list
HOL  Kananaskis-13