PLOGHELP COMPATIBILITY      Jonathan Laventhol, Thursday 22nd March 1984
                                Revised by Kathryn Seifert  October 1986


This file describes DEC10 predicates which are not implemented in POPLOG
Prolog, with suggestions on how to get around their absence.  See also
the file PLOGHELP * POPLOG which describes other differences.


-- MISSING BUILT IN PREDICATES ----------------------------------------

'C'(A,B,C)
    This is not implemented.  As the DEC10 manual says, it isn't that
    useful. If you need it, it's this:

        'C'([X|Y], X, Y).

'LC'
'NOLC'
    This is defined as being system dependant. POPLOG Prolog uses the LC
    convention.

erase(A)
instance(A,B)
recorda(A,B,C)
recorded(A,B,C)
recordz(A,B)
    These facilities are provided in a library file.
    See PLOGHELP * RECORD

unknown(A,B)
    These facilities are provided in a library file.
    See PLOGHELP * UNKNOWN

ancestors(X)
subgoal_of(A)
depth(A)
maxdepth(A)
    Our system is a compiler, and these are not usually implemented in
    compiled Prolog systems.  It is possible to get the effect of
    maxdepth because a mishap occurs when the recursion stack overflows:
    see PLOGHELP * SYSTEM for more information about setting memory
    limits. Our intention is to provide ancestors/1 (and hence
    subgoal_of) eventually.

assert(C,R)
asserta(C,R)
assertz(C,R)
clause(H,T,R)
    Use normal assert/1, asserta/1, assertz/1, retract/1, or use
    library(record).

compactcode
fastcode
    There are no flags to control the time/space tradeoff of the
    compiled code. For information, unification of heads of clauses is
    done by inline code where the structures no more complex than one
    level deep.  Other unification is done by out-of-line code.

    For optimisation information, see PLOGHELP * EFFICIENCY

fileerrors
nofileerrors
    It is possible to redefine the actions for any given error.  See
    PLOGHELP * ERROR

gc
nogc
gcguide(A,B,C)
    Garbage collection is always enabled in POPLOG Prolog.  It is
    possible to tune the collections by use of predicates
    prolog_gcratio/1, prolog_memlim/1 and prolog_area_lim/1.  See
    PLOGHELP * SYSTEM

log
nolog
    These facilities are defined in a library file.  See PLOGHELP * LOG

mode X
    Mode declarations are not yet supported by this Prolog.
    Use var/1 and nonvar/1.

public X
revive(Name, Arity)
    These are not meaningful in a system with only a compiler.

leash(X)
trace
debug
    These debugging facilities are not yet available.

plsys(Term)
    Interaction with the operating system should rarely be needed.  If
    it is, you should use POP11 facilities.  See HELP * SYSOBEY.


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

PLOGHELP * SYSTEM
 Predicates which affect the way the Prolog system operates

PLOGHELP * POPLOG
 Features of POPLOG Prolog

PLOGHELP * DEC1O
 Library file to change operator precedences to those of DEC10 Prolog

PLOGHELP * EFFICIENCY
 Hints about how to make Prolog programs more efficient


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