( atom(Item) ->
( Item == user ->
catch(load(user_input), E, print_exception_with_check(E))
- ;
- submit_query_and_print_results(consult(Item), [])
+ ; submit_query_and_print_results(consult(Item), [])
)
; catch(type_error(atom, Item, repl/0),
E,
)
; Term = end_of_file ->
halt
- ;
- submit_query_and_print_results(Term, VarList)
+ ; submit_query_and_print_results(Term, VarList)
).
-%% run_query(+QueryChars, +Callback_2, +Options)
+%% run_query(+QueryChars, +Callback_3, +Options)
%
-% Runs a query from a string of chars, calling `Callback_2` on each leaf answer.
+% Runs a query from a string of chars, calling `Callback_3` on each leaf answer.
% See `run_query_goal/4` for details.
-run_query(QueryChars, Callback_2, Options) :-
+run_query(QueryChars, Callback_3, Options) :-
read_term_from_chars(QueryChars, QueryGoal, [variable_names(VarNames)]),
- run_query_goal(QueryGoal, VarNames, Callback_2, Options).
+ run_query_goal(QueryGoal, VarNames, Callback_3, Options).
-%% run_query_goal(+QueryGoal, +VarNames, +Callback_2, +Options)
+%% run_query_goal(+QueryGoal, +VarNames, +Callback_3, +Options)
%
-% Run a query from a goal, calling `Callback_2` on each leaf answer.
+% Run a query from a goal, calling `Callback_3` 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 first arguments to `Callback_2` are:
+% is an atom and `Var` is a variable. `Callback_3` should have the form
+% `callback(+LeafAnswer, +Info, -Stop)`, where `LeafAnswer` will be one of those:
%
% - `final(false)`
% - `final(exception(Exception))`, where `Exception` is the exception thrown
% 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.
%
-% The second argument is a list with extra information that can be activated with options.
+% The second argument of the callback (`Info`) is a list with extra information that can
+% be activated with options. The third argument `Stop` controls whether the query will continue
+% or stop, and should be instantiated by the callback to either `continue` or `stop`.
%
% `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_2, _) :-
+run_query_goal(QueryGoal, VarNames, Callback_3, _) :-
% 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
% if we are still inside the query or not.
),
( Excepted == true ->
!,
- call(Callback_2, final(exception(Exception)), [])
+ call(Callback_3, final(exception(Exception)), [], _)
; ( VarNames == [], ResGoals == [] ->
( Pending == true ->
- call(Callback_2, pending(true), [])
- ; call(Callback_2, final(true), [])
+ call(Callback_3, pending(true), [], Stop),
+ ( Stop == stop -> !
+ ; Stop == continue -> true
+ ; domain_error(stop_or_continue, Stop, run_query_goal/4)
+ )
+ ; call(Callback_3, final(true), [], _)
)
; copy_term([Vars1, ResVars], [Vars1, ResVars], ResGoals),
term_variables(ResGoals, ResGoalVars),
term_variables(Vars3, Vars4), % deduplicate vars of Vars1 but preserve their order.
charsio:extend_var_list(Vars4, VarNames, NewVarNames1, fabricated),
( Pending == true ->
- call(Callback_2, pending(leaf_answer(Bindings, ResGoals, NewVarNames1)), [])
- ; call(Callback_2, final(leaf_answer(Bindings, ResGoals, NewVarNames1)), [])
+ call(
+ Callback_3,
+ pending(leaf_answer(Bindings, ResGoals, NewVarNames1)),
+ [],
+ Stop
+ ),
+ ( Stop == stop -> !
+ ; Stop == continue -> true
+ ; domain_error(stop_or_continue, Stop, run_query_goal/4)
+ )
+ ; call(Callback_3, final(leaf_answer(Bindings, ResGoals, NewVarNames1)), [], _)
)
)
).
-run_query_goal(_, _, Callback_2, _) :-
+run_query_goal(_, _, Callback_3, _) :-
% If the whole query failed or we didn't cut in the previous definition of
% run_query_goal/4 (which means we are still in the query but it has failed)
% then we get here so we have a (tail) false.
- call(Callback_2, final(false), []).
+ call(Callback_3, final(false), [], _).
submit_query_and_print_results(QueryTerm, VarNames) :-
bb_put('$answer_count', 0),
bb_put('$report_all', false),
bb_put('$report_n_more', 0),
- catch(
- run_query_goal(QueryTerm, VarNames, toplevel_query_callback, []),
- '$stop_query',
- true
- ).
+ run_query_goal(QueryTerm, VarNames, toplevel_query_callback, []).
handle_first_answer :-
( bb_get('$answer_count', 0) ->
Count is Count0 + 1,
bb_put('$answer_count', Count).
-toplevel_query_callback(pending(LeafAnswer), _) :-
+toplevel_query_callback(pending(LeafAnswer), _, Stop) :-
handle_first_answer,
increment_answer_count,
write_leaf_answer(LeafAnswer, []),
- read_input(LeafAnswer).
-toplevel_query_callback(final(LeafAnswer), _) :-
+ read_input(LeafAnswer, Stop).
+toplevel_query_callback(final(LeafAnswer), _, continue) :-
( exception(Exception) = LeafAnswer ->
print_exception(Exception)
; handle_first_answer,
; write_eq(ThreadedGoals, VarNames, 20)
).
-read_input(LeafAnswer) :-
+read_input(LeafAnswer, Stop) :-
( bb_get('$report_all', true) ->
C = n
; bb_get('$report_n_more', N), N > 1 ->
C = n
; get_single_char(C)
),
- ( C = w ->
- nl,
- write(' '),
- write_leaf_answer(LeafAnswer, [depth(deep)]),
- read_input(LeafAnswer)
- ; C = p ->
- nl,
- write(' '),
- write_leaf_answer(LeafAnswer, [depth(shallow)]),
- read_input(LeafAnswer)
- ; member(C, [';', ' ', n]) ->
- nl, write('; ')
- ; C = h ->
- help_message,
- read_input(LeafAnswer)
- ; member(C, ['\n', .]) ->
+ ( member(C, ['\n', .]) ->
nl, write('; ... .'), nl,
- throw('$stop_query')
- ; C = a ->
- bb_put('$report_all', true),
- nl, write('; ')
- ; C = f ->
- bb_get('$answer_count', Count),
- More is 5 - Count mod 5,
- bb_put('$report_n_more', More),
- nl, write('; ')
- ; read_input(LeafAnswer)
+ Stop = stop
+ ; Stop = continue,
+ ( C = w ->
+ nl,
+ write(' '),
+ write_leaf_answer(LeafAnswer, [depth(deep)]),
+ read_input(LeafAnswer)
+ ; C = p ->
+ nl,
+ write(' '),
+ write_leaf_answer(LeafAnswer, [depth(shallow)]),
+ read_input(LeafAnswer)
+ ; member(C, [';', ' ', n]) ->
+ nl, write('; ')
+ ; C = h ->
+ help_message,
+ read_input(LeafAnswer)
+ ; C = a ->
+ bb_put('$report_all', true),
+ nl, write('; ')
+ ; C = f ->
+ bb_get('$answer_count', Count),
+ More is 5 - Count mod 5,
+ bb_put('$report_n_more', More),
+ nl, write('; ')
+ ; read_input(LeafAnswer)
+ )
).
needs_bracketing(Value, Op) :-
projects / scryer-prolog.git / commitdiff