Module Control.AllValues

getAllValues :: a -> IO [a]   

Gets all values of an expression (similarly to Prolog's findall). Conceptually, all values are computed on a copy of the expression, i.e., the evaluation of the expression does not share any results. In PAKCS, the evaluation suspends as long as the expression contains unbound variables or the computed values contain unbound variables.

getOneValue :: a -> IO (Maybe a)   

Gets one value of an expression. Returns Nothing if the search space is finitely failed. Conceptually, the value is computed on a copy of the expression, i.e., the evaluation of the expression does not share any results. In PAKCS, the evaluation suspends as long as the expression contains unbound variables or the computed value contains unbound variables.

getAllSolutions :: Data a => (a -> Bool) -> IO [a]   

Gets all solutions to a constraint. Conceptually, all solutions are computed on a copy of the constraint, i.e., the evaluation of the constraint does not share any results. Moreover, this evaluation suspends if the constraints contain unbound variables. Similar to Prolog's findall.

getOneSolution :: Data a => (a -> Bool) -> IO (Maybe a)   

Gets one solution to a constraint. Returns Nothing if the search space is finitely failed.

getAllFailures :: a -> (a -> Bool) -> IO [a]   

Returns a list of values that do not satisfy a given constraint.

Example call:

(getAllFailures x c)

Parameters:

• x : an expression (a generator evaluable to various values)
• c : a constraint that should not be satisfied

Returns:

A list of all values of e such that (c e) is not provable

allValues :: a -> [a]   

Returns all values of an expression. Conceptually, all values are computed on a copy of the expression, i.e., the evaluation of the expression does not share any results. In PAKCS, the evaluation suspends as long as the expression contains unbound variables or the computed values contain unbound variables.

Note that this operation is not purely declarative since the ordering of the computed values depends on the ordering of the program rules.

someValue :: a -> a   

Returns some value for an expression. If the expression has no value, the computation fails. Conceptually, the value is computed on a copy of the expression, i.e., the evaluation of the expression does not share any results. In PAKCS, the evaluation suspends as long as the expression contains unbound variables or the computed value contains unbound variables.

Note that this operation is not purely declarative since the computed value depends on the ordering of the program rules. Thus, this operation should be used only if the expression has a single value.

oneValue :: a -> Maybe a   

Returns just one value for an expression. If the expression has no value, Nothing is returned. Conceptually, the value is computed on a copy of the expression, i.e., the evaluation of the expression does not share any results. In PAKCS, the evaluation suspends as long as the expression contains unbound variables or the computed value contains unbound variables.

Note that this operation is not purely declarative since the computed value depends on the ordering of the program rules. Thus, this operation should be used only if the expression has a single value.

allSolutions :: Data a => (a -> Bool) -> [a]   

Returns all values satisfying a predicate, i.e., all arguments such that the predicate applied to the argument can be evaluated to True. In PAKCS, the evaluation suspends as long as the predicate expression contains unbound variables or the computed values contain unbound variables.

Note that this operation is not purely declarative since the ordering of the computed values depends on the ordering of the program rules.

someSolution :: Data a => (a -> Bool) -> a   

Returns some value satisfying a predicate, i.e., some argument such that the predicate applied to the argument can be evaluated to True. If there is no value satisfying the predicate, the computation fails.

Note that this operation is not purely declarative since the ordering of the computed values depends on the ordering of the program rules. Thus, this operation should be used only if the predicate has a single solution.

oneSolution :: Data a => (a -> Bool) -> Maybe a   

Returns just one value satisfying a predicate. If there is no such value, Nothing is returned

Note that this operation is not purely declarative since the computed value depends on the ordering of the program rules. Thus, this operation should be used only if the expression has a single value.

isFail :: a -> Bool   

Does the computation of the argument to a head-normal form fail? Conceptually, the argument is evaluated on a copy, i.e., even if the computation does not fail, it has not been evaluated.

rewriteAll :: a -> [a]   

Gets all values computable by term rewriting. In contrast to allValues, this operation does not wait until all "outside" variables are bound to values, but it returns all values computable by term rewriting and ignores all computations that requires bindings for outside variables.

rewriteSome :: a -> Maybe a   

Similarly to rewriteAll but returns only some value computable by term rewriting. Returns Nothing if there is no such value.