Category : Files from Magazines
Archive   : AIJLAG87.ZIP
Filename : UTILITY.ARI

% Top Level Compiler Procedures and Utilities
% LLO 12-30-85
% File: UTILITY.ARI
% (C) 1986,1987 Louis L. Odette. All Rights Reserved.

/* These are the top-level compiler procedures */

% compile_file may need to be adapted for your file system

compile_file(File) :-
seeing(Oldfile),see(File),repeat,
compile(P,Code),
(is_endfile(Code) ; write_code(P,Code),fail),
seen,see(Oldfile).

compile(P,Code) :-
compile_clause(P,Nvars,Code),
(is_endfile(Code) ;
(retract(procedure(P,Clauses)),
concat(Clauses,[clause(Nvars,Code)],NewClauses),
assert(procedure(P,NewClauses));
assert(procedure(P,[clause(Nvars,Code)])))),!.

compile_clause(P,Nvars,Code) :-
get0(Char),
(is_endfile(Char),Code = Char;
read_until(Char,".",Rest),!,
chars_to_words([Char|Rest],Sent),
clause(Vars,[],Cd,P,Sent,_),nrev(Cd,Code),
is_newline(E),read_until([E],_),
memberchkN(-1,Vars,-1,Nvars)).


/* Utilities */

% member

member(X,[X|_]).
member(X,[_|L]) :- member(X,L).

% memberchk

memberchk(X,[X|_]) :- !.
memberchk(X,[_|T]) :- memberchk(X,T).

% memberchkN

memberchkN(X,[X|_],M,N) :- N is M+1,!.
memberchkN(X,[_|T],L,N) :- M is L+1,memberchkN(X,T,M,N).

% naive reverse

nrev([X|L0],L) :-
nrev(L0,L1),concat(L1,[X],L).
nrev([],[]).

% concatenate

concat([],L,L).
concat([X|L1],L2,[X|L3]) :- concat(L1,L2,L3).

% write_code

write_code(P,Code) :-
write(P),nl,write(Code),nl,!.