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ADDED: New Prolog flag, answer_write_options.

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This lets us specify additional write options used by the top level
for writing answers.
This commit is contained in:
Markus Triska
2023-09-03 09:33:16 +02:00
parent 66f6399b8a
commit c934e06171
2 changed files with 31 additions and 8 deletions
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22
src/lib/builtins.pl
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@@ -143,6 +143,7 @@ call(_, _, _, _, _, _, _, _, _).
% enabled) and `error` which throws an exception when a cylic term is created. Read and write.
% * `unknown`: How undefined predicates are handled when called. Possible values are `error` (the default, an error is thrown),
% `fail` (the call silently fails) and `warn` (the call fails and a warning about the undefined predicate is printed).
% * `answer_write_options`: Additional write options used by the top level for writing answers.
%
current_prolog_flag(Flag, Value) :- Flag == max_arity, !, Value = 1023.
current_prolog_flag(max_arity, 1023).
@@ -160,6 +161,12 @@ current_prolog_flag(Flag, OccursCheckEnabled) :-
Flag == occurs_check,
!,
'$is_sto_enabled'(OccursCheckEnabled).
current_prolog_flag(Flag, Value) :-
Flag == answer_write_options,
!,
( iso_ext:bb_get('$answer_write_options', Value) -> true
; Value = []
).
current_prolog_flag(Flag, _) :-
atom(Flag),
throw(error(domain_error(prolog_flag, Flag), current_prolog_flag/2)). % 8.17.2.3 b
@@ -207,14 +214,25 @@ set_prolog_flag(occurs_check, false) :-
set_prolog_flag(occurs_check, error) :-
!, '$set_sto_with_error_as_unify'.
set_prolog_flag(double_quotes, Value) :-
throw(error(domain_error(flag_value, double_quotes + Value),
set_prolog_flag/2)). % 8.17.1.3 e
flag_domain_error(double_quotes, Value).
set_prolog_flag(answer_write_options, Options) :-
!,
catch(catch(builtins:parse_write_options(Options, _, set_prolog_flag/2),
error(domain_error(_,_), _),
throw(error(type_error(_,_), _))), % convert domain error to type error ....
error(type_error(_,_), _), % ... to catch type and domain errors.
flag_domain_error(answer_write_options, Options)),
iso_ext:bb_put('$answer_write_options', Options).
set_prolog_flag(Flag, _) :-
atom(Flag),
throw(error(domain_error(prolog_flag, Flag), set_prolog_flag/2)). % 8.17.1.3 d
set_prolog_flag(Flag, _) :-
throw(error(type_error(atom, Flag), set_prolog_flag/2)). % 8.17.1.3 c
flag_domain_error(Flag, Value) :-
% domain error via 8.17.1.3 e: Value is inappropriate for Flag
throw(error(domain_error(flag_value, Flag + Value), set_prolog_flag/2)).
% control operators.
%% fail.