diogo/yap-6.3
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move gramar preprocessing here.

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This commit is contained in:
Vítor Santos Costa 2014-10-02 14:39:45 +01:00
parent b1a6f092fd
commit 5bae8321d7
1 changed files with 75 additions and 3 deletions
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78
pl/arith.yap
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@ -28,7 +28,6 @@
expand_expr/5,
expand_expr/6] ).
:- use_system_module( '$_errors', ['$do_error'/2]).
:- use_system_module( '$_modules', ['$clean_cuts'/2]).
@ -60,8 +59,7 @@
*/
/**
@pred expand_exprs(- _O_,+ _N_)
/** @pred expand_exprs(- _O_,+ _N_)
Control term expansion during compilation.
Enables low-level optimizations. It reports the current state by
@ -86,6 +84,7 @@ expand_exprs(Old,New) :-
After a call to this predicate, arithmetical expressions will be compiled.
(see example below). This is the default behavior.
*/
compile_expressions :- set_value('$c_arith',true).
/** @pred do_not_compile_expressions
@ -198,6 +197,31 @@ do_c_built_in(Comp0, _, R) :- % now, do it for comparisons
expand_expr(F, Q, V),
'$do_and'(P, Q, R0),
'$do_and'(R0, Comp, R).
do_c_built_in(phrase(NT,Xs), NTXsNil) :-
'$_arith':do_c_built_in(phrase(NT,Xs,[]), NTXsNil).
do_c_built_in(phrase(NT,Xs0,Xs), Mod, NewGoal) :-
'$goal_expansion_allowed'(phrase(NT,Xs0,Xs), Mod),
Goal = phrase(NT,Xs0,Xs),
callable(NT),
catch('$translate_rule'((pseudo_nt --> NT), Rule),
error(Pat,ImplDep),
( \+ '$harmless_dcgexception'(Pat),
throw(error(Pat,ImplDep))
)),
Rule = (pseudo_nt(Xs0c,Xsc) :- NewGoal0),
Goal \== NewGoal0,
% apply translation only if we are safe
\+ '$contains_illegal_dcgnt'(NT), !,
( var(Xsc), Xsc \== Xs0c
-> Xs = Xsc, NewGoal1 = NewGoal0
; NewGoal1 = (NewGoal0, Xsc = Xs)
),
( var(Xs0c)
-> Xs0 = Xs0c,
NewGoal = NewGoal1
; ( Xs0 = Xs0c, NewGoal1 ) = NewGoal
).
do_c_built_in(P, _, P).
do_c_built_metacall(G1, Mod, '$execute_wo_mod'(G1,Mod)) :-
@ -369,6 +393,54 @@ expand_expr(Op, X, Y, O, Q, P) :-
'$preprocess_args_for_non_commutative'(X, Y, Z, W, E) :-
'$do_and'(Z = X, Y = W, E).
do_c_built_in(phrase(NT,Xs), NTXsNil) :-
'$_arith':do_c_built_in(phrase(NT,Xs,[]), NTXsNil).
do_c_built_in(phrase(NT,Xs0,Xs), Mod, NewGoal) :-
'$goal_expansion_allowed'(phrase(NT,Xs0,Xs), Mod),
Goal = phrase(NT,Xs0,Xs),
callable(NT),
catch('$translate_rule'((pseudo_nt --> NT), Rule),
error(Pat,ImplDep),
( \+ '$harmless_dcgexception'(Pat),
throw(error(Pat,ImplDep))
)),
Rule = (pseudo_nt(Xs0c,Xsc) :- NewGoal0),
Goal \== NewGoal0,
% apply translation only if we are safe
\+ '$contains_illegal_dcgnt'(NT), !,
( var(Xsc), Xsc \== Xs0c
-> Xs = Xsc, NewGoal1 = NewGoal0
; NewGoal1 = (NewGoal0, Xsc = Xs)
),
( var(Xs0c)
-> Xs0 = Xs0c,
NewGoal = NewGoal1
; ( Xs0 = Xs0c, NewGoal1 ) = NewGoal
).
'$goal_expansion_allowed'(phrase(_NT,_Xs0,_Xs), _Mod).
%% contains_illegal_dcgnt(+Term) is semidet.
%
% True if Term contains a non-terminal we cannot deal with using
% goal-expansion. The test is too general approximation, but safe.
'$contains_illegal_dcgnt'(NT) :-
functor(NT, _, A),
between(1, A, I),
arg(I, NT),
nonvar(I),
( I = ! ; I = phrase(_,_,_) ), !.
% write(contains_illegal_nt(NT)), % JW: we do not want to write
% nl.
'$harmless_dcgexception'(instantiation_error). % ex: phrase(([1],x:X,[3]),L)
'$harmless_dcgexception'(type_error(callable,_)). % ex: phrase(27,L)
/**
@}