-spec first_match(hookpoint(), _Input) -> {value,
                                           _Return} |
                                          false.

Pass Val to functions registered at HookPoint. Stop iteration and return {value, Ret} when hook returns {true, Ret}. Otherwise return false.

-spec foreach(hookpoint(), term()) -> boolean().

Pass Arg to all functions registered at HookPoint. The hook type must be (Arg) -> boolean(). The return value is a boolean, calculated similar to lists:any/2.

-spec fold(hookpoint(), Acc) -> Acc.

If F1, F2, ..., FN are hooks registered at HookPoint, return FN(...(F2(F1(Acc0))).

-spec traverse(fun((fun(), Acc) -> {boolean(), Acc}),
               Acc, hookpoint()) -> Acc.

A generic function that traverses through hooks registered at HookPoint and passes them as an argument to Fun together with the accumulator value.

Fun should return a tuple where the first element is a boolean and the second is new value of the accumulator.

If it returns {true, Acc2} and the next hook exists, Fun will be called again the next next hook and the new value of the accumulator as arguments. Otherwise iteration stops and accumulator is returned.

-spec add(hookpoint(), integer(), fun()) -> ok.

Add a hook Fun to the HookPoint with the given priority.

Hooks with a higher priority are executed earlier.

-spec add(hookpoint(), fun()) -> ok.

Add a hook Fun to the HookPoint with default priority (0).