🚀 go-pugleaf

From article <1a3srjINNsgm@darkstar.UCSC.EDU>, by kjell@cse.ucsc.edu (Kjell Post):
 
> Let me explain by an example what I'm looking for.  I want to write a
> program that works for both SICStus Prolog and Sepia.  The problem is
> that I need to retract all clauses foo/n when the program is started.
> Now, in SICStus the procedure is called retractall/2, but in Sepia it
> is retract_all/2.  That extra underscore (or absence of it) is really 
> annoying!  So I'd like to hear about efficient and portable tricks to
> write code that works in both languages.

    invent some novel name for the facility you require
    (e.g. retract_all_matching_unit_clauses)

    write your portable code in terms of this

    write compatibility libraries for each target Prolog implementation
    e.g.
	retract_all_matching_unit_clauses( X) :-
		retractall( X).

    to port to Prolog X:

	link your source with the Prolog X compatibility library (linking
	in Prolog is particularly trivial: 'cat' does it)

	feed the result through a general-purpose partial evaluator
	(e.g. Dan Sahlin's Mixtus) to eliminate the redundant procedures.

----
  __   __    Paul Singleton (Mr)           JANET: paul@uk.ac.keele.cs
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 |  .  __).  Keele University, Newcastle,    tel: +44 (0)782 621111 x7355
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