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streamline and fix phrase/{2,3} (#1237)

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This commit is contained in:
Mark Thom
2022-01-19 20:07:15 -07:00
parent 6462c524f4
commit 11b96875e0
1 changed files with 22 additions and 47 deletions
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69
src/lib/dcgs.pl
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@@ -25,47 +25,48 @@ load_context(GRBody, Module, GRBody0) :-
:- meta_predicate phrase(2, ?, ?).
phrase(GRBody, S0) :-
phrase(GRBody, S0, []).
load_context(GRBody, Module, GRBody0),
phrase(GRBody0, S0, [], Module).
phrase(GRBody, S0, S) :-
load_context(GRBody, Module, GRBody0),
phrase(GRBody0, S0, S, Module).
phrase(GRBody, S0, S, Module) :-
( var(GRBody) ->
throw(error(instantiation_error, phrase/3))
; load_context(GRBody, Module, GRBody0),
dcg_constr(GRBody0) ->
( var(Module) ->
phrase_(GRBody0, S0, S)
; phrase_(GRBody0, S0, S, Module)
)
; functor(GRBody, _, _) ->
call(GRBody, S0, S)
; throw(error(type_error(callable, GRBody), phrase/3))
; dcg_constr(GRBody) ->
phrase_(GRBody, S0, S, Module)
; callable(GRBody) ->
call(Module:GRBody, S0, S)
; throw(error(type_error(callable, Module:GRBody), phrase/3))
).
phrase_([], S, S, _).
phrase_(!, S, S, _).
phrase_((A, B), S0, S, M) :-
phrase(M:A, S0, S1),
phrase(M:B, S1, S).
phrase(A, S0, S1, M),
phrase(B, S1, S, M).
phrase_((A -> B ; C), S0, S, M) :-
( phrase(M:A, S0, S1) ->
phrase(M:B, S1, S)
; phrase(M:C, S0, S)
( phrase(A, S0, S1, M) ->
phrase(B, S1, S, M)
; phrase(C, S0, S, M)
).
phrase_((A ; B), S0, S, M) :-
( phrase(M:A, S0, S)
; phrase(M:B, S0, S)
( phrase(A, S0, S, M)
; phrase(B, S0, S, M)
).
phrase_((A | B), S0, S, M) :-
( phrase(M:A, S0, S)
; phrase(M:B, S0, S)
( phrase(A, S0, S, M)
; phrase(B, S0, S, M)
).
phrase_({G}, S, S, M) :-
call(M:G).
phrase_(call(G), S0, S, M) :-
call(M:G, S0, S).
phrase_((A -> B), S0, S, M) :-
( phrase(M:A, S0, S1) ->
phrase(M:B, S1, S)
( phrase(A, S0, S1, M) ->
phrase(B, S1, S, M)
; fail
).
phrase_(phrase(NonTerminal), S0, S, M) :-
@@ -73,32 +74,6 @@ phrase_(phrase(NonTerminal), S0, S, M) :-
phrase_([T|Ts], S0, S, _) :-
append([T|Ts], S, S0).
phrase_([], S, S).
phrase_(!, S, S).
phrase_(M:G, S0, S) :-
phrase_(G, S0, S, M).
phrase_((A, B), S0, S) :-
phrase(A, S0, S1),
phrase(B, S1, S).
phrase_((A -> B ; C), S0, S) :-
( phrase(A, S0, S1) ->
phrase(B, S1, S)
; phrase(C, S0, S)
).
phrase_((A ; B), S0, S) :-
( phrase(A, S0, S) ; phrase(B, S0, S) ).
phrase_((A | B), S0, S) :-
( phrase(A, S0, S) ; phrase(B, S0, S) ).
phrase_({G}, S0, S) :-
( call(G), S0 = S ).
phrase_(call(G), S0, S) :-
call(G, S0, S).
phrase_((A -> B), S0, S) :-
phrase((A -> B ; fail), S0, S).
phrase_(phrase(NonTerminal), S0, S) :-
phrase(NonTerminal, S0, S).
phrase_([T|Ts], S0, S) :-
append([T|Ts], S, S0).
% The same version of the below two dcg_rule clauses, but with module scoping.
dcg_rule(( M:NonTerminal, Terminals --> GRBody ), ( M:Head :- Body )) :-