%How many rules apply? (Note: List order in AllOperations is random)

:- condition(possible_operations/2).

possible_operations(AllOperations, N) :-
    findall(Operation, ( match(Operation, 1321388953) ), AllOperations),
    length(AllOperations, N).

%Select an operation and add others to Choice Points

:- rule([fire_once],
        [possible_operations([Operation|OtherOps], N),
         N > 1,
         match(Stack, 1321298902),
         match(PreviousWords, 1321291544)],
        [delete_all(_, 1321388953),
         add(Operation, 1321388953),
         send(push(cp(Stack, PreviousWords, OtherOps)), 1321906946)]).

%Either there is still input left, or the stack is not empty

:- condition(not_valid/0).

not_valid :-
    match(_, 1321278717),
    not( (match(eos, 1321278717)) ).
not_valid :-
    match(eos, 1321278717),
    not( (match([], 1321298902)) ).

%Restore stack at last choice point

:- rule([triggered(system_quiescent), fire_once],
        [not_valid,
         match(cp(Stack, _, _), 1321906946),
         match(OldStack, 1321298902)],
        [delete(OldStack, 1321298902),
         add(Stack, 1321298902)]).

%Re-add untried alternatives to Possible Operations (Note: Fires once per operation)

:- rule([triggered(system_quiescent)],
        [not_valid,
         match(cp(_, _, Operations), 1321906946),
         member(Alternative, Operations)],
        [add(Alternative, 1321388953)]).

%Returns the beginning of the sentence and the words to reprocess

:- condition(reprocess/2).

reprocess(SentenceBegin, NewReProcess) :-
    match(cp(_, SentenceBegin, _), 1321906946),
    match(PreviousWords, 1321291544),
    match(ExistingContent, 1322000411),
    append(NewReversed, SentenceBegin, PreviousWords),
    reverse(NewReversed, NewContent),
    append(NewContent, ExistingContent, NewReProcess).

%Compute the words to be re-processed (first Current Word, then ReProcess)

:- rule([triggered(system_quiescent), fire_once],
        [not_valid,
         reprocess([NewCurrentWord|OldWords], ReProcess)],
        [delete(_, 1321278717),
         delete(_, 1321291544),
         delete(_, 1322000411),
         add(NewCurrentWord, 1321278717),
         add([NewCurrentWord|OldWords], 1321291544),
         add(ReProcess, 1322000411)]).

%Pop last choice point

:- rule([triggered(system_quiescent), fire_once],
        [not_valid,
         match(_, 1321906946)],
        [send(pop, 1321906946)]).

%Re-process words (akin to "Word-by-Word" + "Read")

:- rule([],
        [match([FirstWord|Rest], 1322000411),
         not( (match(_, 1321278717)) ),
         match(PreviousWords, 1321291544)],
        [delete([FirstWord|Rest], 1322000411),
         add(Rest, 1322000411),
         add(FirstWord, 1321278717),
         delete(PreviousWords, 1321291544),
         add([FirstWord|PreviousWords], 1321291544)]).

%Send a signal to the module when a parse is found

:- rule([refracted],
        [match([], 1321298902),
         match(eos, 1321278717)],
        [send(parse_found, 1321277146)]).

%Send a signal to the module when the parser gives up

:- rule([triggered(system_quiescent), refracted],
        [not_valid,
         not( (match(_, 1321906946)) )],
        [send(parsing_failed, 1321277146)]).