PLOGHELP USEFUL                          Kathryn Seifert  September 1986

Library program defining some useful predicates.

LIB * USEFUL contains definitions of the potentially useful predicates
member/2, append/3, once/1, uses/1 and load/1. You can load the library
with the directive:

    :- library(useful).

The predicates are described in the following HELP files:

PLOGHELP * APPEND
    List concatenation

PLOGHELP * LOAD
    Synonym for reconsult

PLOGHELP * MEMBER
    List membership

PLOGHELP * ONCE
    Calls a goal without backtracking

PLOGHELP * USES
    Once-only library mechanism


-- RELATED DOCUMENTATION ----------------------------------------------

PLOGHELP * LIBRARY
    How to use the library mechanism.

LIB * USEFUL
    The library source code.

--- C.all/plog/help/useful ---------------------------------------------
--- Copyright University of Sussex 1988. All rights reserved. ----------
