B.7  Passing Control and Data to ECLⁱPS^e from C++

These are the functions needed to embed ECLⁱPS^e into C++ code.

void post_goal(const EC_word)

void post_goal(const char *)

post a goal (constraint) that will be executed when ECLⁱPS^e is resumed.

int EC_resume(EC_word FromC, EC_ref& ToC)

int EC_resume(EC_word FromC)

int EC_resume()

resume execution of the ECLⁱPS^e engine: All posted goals will be executed. The return value will be EC_succeed if the goals succeed (in this case the ToC argument returns a cut value that can be used to discard alternative solutions). EC_fail is returned if the goals fail, and EC_yield if control was yielded because of a yield/2 predicate call in the ECLⁱPS^e code (in this case, ToC contains the data passed by the first argument of yield/2). If a writable queue stream with yield-option (see open/4) was flushed, the return value is PFLUSHIO and ToC contains the associated stream number. If there was an attempt to read from an empty queue stream with yield-option, the return value is PWAITIO and ToC contains the associated stream number. Moreover, if the previous EC_resume yielded due to a yield/2 predicate call, The term FromC is passed as input into the second argument of yield/2 on resuming.

void EC_ref::cut_to()

Should be applied to the ToC cut return value of an EC_resume(). Cut all choicepoints created by the batch of goals whose execution succeeded.

int post_event(EC_word Name)

Post an event to the ECLⁱPS^e engine. This will lead to the execution of the corresponding event handler once the ECLⁱPS^e execution is resumed. See also event/1 and the User Manual chapter on event handling for more information. Name should be an ECLⁱPS^e atom.