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Documentation for run_query/3 and run_query_goal/4

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bakaq
2024-09-06 14:55:39 -03:00
parent afa7af3de6
commit e369c15a27
1 changed files with 33 additions and 3 deletions
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36
src/toplevel.pl
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@@ -205,10 +205,40 @@ instruction_match(Term, VarList) :-
submit_query_and_print_results(Term, VarList)
).
run_query(Query, Callback_1, Options) :-
read_term_from_chars(Query, QueryTerm, [variable_names(VarNames)]),
run_query_goal(QueryTerm, VarNames, Callback_1, Options).
%% run_query(+QueryChars, +Callback_1, +Options)
%
% Runs a query from a string of chars, calling `Callback_1` on each leaf answer.
% See `run_query_goal/4` for details.
run_query(QueryChars, Callback_1, Options) :-
read_term_from_chars(QueryChars, QueryGoal, [variable_names(VarNames)]),
run_query_goal(QueryGoal, VarNames, Callback_1, Options).
%% run_query_goal(+QueryGoal, +VarNames, +Callback_1, +Options)
%
% Run a query from a goal, calling `Callback_1 on each leaf answer.
% `VarNames` needs to have the same format as the one from the `variable_names(-VarNames)`
% option in `read_term/3`. That is, a list of terms of the form `Name=Var`, where `Name`
% is an atom and `Var` is a variable. The possible arguments to `Callback_1` are:
%
% - `final(false)`
% - `final(exception(Exception))`, where `Exception` is the exception thrown
% - `final(true)`
% - `final(leaf_answer(Bindings, ResidualGoals, VarNames))`, where:
%
% - `Bindings` is a list of terms of the form `Var=Term`, where `Var` is a
% variable.
% - `ResidualGoals` is a list of the residual goals from the query.
% - `VarNames` is a list of `Name=Var` terms where `Name` is an atom and `Var` is a
% variable.
% - `pending(true)`
% - `pending(leaf_answer(Bindings, ResidualGoals, VarNames)`, see `final(leaf_answer(_,_,_))`
% above.
%
% The variants with principal functor `final/1` mean that there will be no more leaf answers,
% and the ones with `pending/1` mean that there will be more leaf answers.
%
% `Option` is a list of options. There are none currently, but in the future support for
% inference limits and timeouts may be implemented.
run_query_goal(QueryGoal, VarNames, Callback_1, _) :-
% The b value in the WAM basically represents which choicepoint we are at.
% By recording it before and after we can then compare the values to know