Question

我从这里发现了关于DCTG的信息：http://cmsmcq.com/2004/lgintro.html#id2631925，我不能在生活中使用SWI prolog，甚至可以找到任何文档。

Answer 1

我从http://www.cs.cmu.edu/afs/cs/project/ai-repository/ai/lang/prolog/code/syntax/dctg/获得了dctg.tgz。

存在问题，因为此类代码是使用旧运算符优先级编写的，范围从1到255，而目前所有系统的范围都是1到1200.这是一个修补的dctg.pl， - 至少 - 你可以毫无错误地进行咨询，然后允许

?- % /home/carlo/prolog/dctg/dctg compiled 0.01 sec, 37 clauses
dctg_reconsult('dctgtest.pl').
true .

免责声明：更正仅基于原始dctg.pl报告的语法错误和警告

% patched dctg.pl, answering http://stackoverflow.com/q/32701614/874024

/*  DCTG.PL  */

/*  Shelved on 21st August 1990.  */


/*
This file defines a DCTG translator as described in ...

It makes a few changes ... operator prec ... from

It also defines the predicate dctg_reconsult, for loading
grammars from file. The specification follows. */


/*  dctg_reconsult( File+ ):
        File: a filename (atom).
    Loads the DCTG grammar in File, converting it to internal
    form useable by the parser.

    dctg_reconsult expects the following terms in its file:
        ?- (X)                  Call X, and go on to the next term.
        :- (X)                  Call X, and go on to the next term.
        X::=Y                   Translate as a DCTG clause, and assert
                                the corresponding Prolog.
        X:-Y                    Assert.
        Any other term X.       Assert.

    dctg_reconsult acts like ordinary reconsult in its dealings with
    repeated clauses. If it meets a clause C with functor and arity
    F,A, then it will always assert the clause. It will delete
    all other clauses for the same functor and arity, provided that
    they did not immediately precede the current one C.

    This applies both to ordinary Prolog clauses, and to DCTG clauses.
*/
:- op( 1045, yfx, ^^ ).
:- op( 1050, xfx, ::= ).
:- op( 1055, xfx, <:> ).
:- op( 1053, xfx, && ).
:- op( 1052, xfx, ::- ).
:- op( 1051, xfx, from ).

translate_rule( (LP::=[]<:>Sem), H ) :-
    !,
    t_lp( LP, [], S, S, Sem, H ).
translate_rule( (LP::=[]), H ) :-
    !,
    t_lp( LP, [], S, S, [], H ).
translate_rule( (LP::=RP<:>Sem), (H:-B) ) :-
    !,
    t_rp( RP, [], StL, S, SR, B1 ),
    reverse( StL, RStL ),
    t_lp( LP, RStL, S, SR, Sem, H ),
    tidy( B1, B ).
translate_rule( (LP::=RP), (H:-B) ) :-
    translate_rule( (LP::=RP<:>[]), (H:-B) ).


t_lp( (LP,List), StL, S, SR, Sem, H ) :-
    append( List, SR, List2 ),
    makelist( Sem, Semantics ),
    add_extra_args( [node(LP,StL,Semantics),S,List2], LP, H ).
t_lp( LP, StL, S, SR, Sem, H ) :-
    makelist( Sem, Semantics ),
    add_extra_args( [node(LP,StL,Semantics),S,SR], LP, H ).


t_rp( !, St, St, S, S, ! ) :- !.
t_rp( [], St, [ [] | St ], S, S1, S=S1 ) :- !.
t_rp( [X], St, [ [X] | St ], S, SR, c(S,X,SR) ) :- !.
t_rp( [X|R], St, [ [X|R] | St ], S, SR, (c(S,X,SR1),RB) ) :-
    !,
    t_rp( R, St, [ R | St ], SR1, SR, RB ).
t_rp( {T}, St, St, S, S, T ) :- !.
t_rp( (T,R), St, StR, S, SR, (Tt,Rt) ) :-
    !,
    t_rp( T, St, St1, S, SR1, Tt ),
    t_rp( R, St1, StR, SR1, SR, Rt ).
t_rp( T^^N, St, [N|St], S, SR, Tt ) :-
    add_extra_args( [N,S,SR], T, Tt ).
t_rp( T, St, [St1|St], S, SR, Tt ) :-
    add_extra_args( [St1,S,SR], T, Tt ).


add_extra_args( L, T, T1 ) :-
    T =.. Tl,
    append( Tl, L, Tl1 ),
    T1 =.. Tl1.


tidy( ((P1,P2),P3), Q ) :-
    tidy( (P1,(P2,P3)), Q ).
tidy( (P1,P2), (Q1,Q2) ) :-
    !,
    tidy( P1, Q1 ),
    tidy( P2, Q2 ).
tidy( A, A ).


c( [X|S], X, S ).


makelist( Sem, [Sem] ) :-
    var( Sem ),
    !.
makelist( (Sem1&&Sem2), [Sem1_|List] ) :-
    !,
    makelist_1( Sem1, Sem1_ ),
    makelist_1( Sem2, Sem2_ ),
    makelist( Sem2_, List ).
makelist( [], [] ) :- !.
makelist( Sem, [Sem] ).


makelist_1( (Attr from Var), Sem ) :-
    !,
    Attr_V =.. [ Attr, _V ],
    Sem = (Attr_V ::- Var^^Attr_V).
makelist_1( Sem, Sem ).


node( _, _, Sem ) ^^ Args :-
    Sem ^^ Args.
[ (Args::-Traverse) | _Rules ] ^^ Args :-
    Traverse.
[ Args | _Rules ] ^^ Args.
[ _ | Rules ] ^^ Args :-
    Rules ^^ Args.

dctg_reconsult( File ) :-
    seeing( CIS ),
    see( File ), seen,
    see( File ),
    dctg_reconsult_1( '$none' ),
    seen,
    see( CIS ).


dctg_reconsult_1( Previous ) :-
    read( Term ),
    (
        Term = end_of_file
    ->
        true
    ;
        process_term( Term, Previous, Next ),
        dctg_reconsult_1( Next )
    ).


process_term( ?-(Term), _, '$none' ) :-
    call( Term ) -> true ; true.

process_term( :-(Term), _, '$none' ) :-
    call( Term ) -> true ; true.

process_term( DCTG, Previous, Next  ) :-
    ( DCTG = (_ ::= _) ; DCTG = (_ <:> _) ),
    !,
    translate_rule( DCTG, Prolog ),
    process_term( Prolog, Previous, Next ).

process_term( :-(Head,Tail), Previous, clause(Functor,Arity) ) :-
    !,
    functor( Head, Functor, Arity ),
    (
        Previous \= clause(Functor,Arity)
    ->
        abolish( Functor, Arity )
    ;
        true
    ),
    assert( (Head:-Tail) ).

process_term( Head, Previous, Next ) :-
    process_term( (Head:-true), Previous, Next ).

SWI prolog是否支持DCTG？

1 个答案: