Safe Haskell	None
Language	Haskell2010

Test.Falsify.Marked

Contents

Description

Marked elements

Intended for qualified import.

import Test.Falsify
import qualified Test.Falsify.Marked as Marked

Synopsis

data Mark
- = Keep
- | Drop
data Marked (f :: Type -> Type) a = Marked {
- getMark :: Mark
- unmark :: f a
}
selectAllKept :: (Traversable t, Selective f) => t (Marked f a) -> f (t (Maybe a))
countKept :: forall t (f :: Type -> Type) a. Foldable t => t (Marked f a) -> Word
shouldKeep :: Marked f a -> Maybe (f a)

Documentation

Should an element in a container be kept or dropped?

Instances details

Show Mark Source #
Instance details Defined in Test.Falsify.Marked Methods showsPrec :: Int -> Mark -> ShowS # show :: Mark -> String # showList :: [Mark] -> ShowS #
Eq Mark Source #
Instance details Defined in Test.Falsify.Marked Methods (==) :: Mark -> Mark -> Bool # (/=) :: Mark -> Mark -> Bool #
Ord Mark Source #
Instance details Defined in Test.Falsify.Marked Methods compare :: Mark -> Mark -> Ordering # (<) :: Mark -> Mark -> Bool # (<=) :: Mark -> Mark -> Bool # (>) :: Mark -> Mark -> Bool # (>=) :: Mark -> Mark -> Bool # max :: Mark -> Mark -> Mark # min :: Mark -> Mark -> Mark #

Marked element in a container

Marking elements can be a useful technique for dropping elements from a container.

Locally marking elements to Drop makes it possible to enforce some global constraints about minimum number of required elements before actually dropping them (see selectAllKept). Example: list.
For containers where we cannot remove random elements, the marks can be used for "outwards propagation": if this element is dropped, then those elements must also be dropped. Example: tree.

Constructors

Marked
Fields getMark :: Mark unmark :: f a

Instances details

Show (f a) => Show (Marked f a) Source #
Instance details Defined in Test.Falsify.Marked Methods showsPrec :: Int -> Marked f a -> ShowS # show :: Marked f a -> String # showList :: [Marked f a] -> ShowS #
Eq (f a) => Eq (Marked f a) Source #
Instance details Defined in Test.Falsify.Marked Methods (==) :: Marked f a -> Marked f a -> Bool # (/=) :: Marked f a -> Marked f a -> Bool #
Ord (f a) => Ord (Marked f a) Source #
Instance details Defined in Test.Falsify.Marked Methods compare :: Marked f a -> Marked f a -> Ordering # (<) :: Marked f a -> Marked f a -> Bool # (<=) :: Marked f a -> Marked f a -> Bool # (>) :: Marked f a -> Marked f a -> Bool # (>=) :: Marked f a -> Marked f a -> Bool # max :: Marked f a -> Marked f a -> Marked f a # min :: Marked f a -> Marked f a -> Marked f a #

Generation

Traverse the argument, generating all values marked Keep, and replacing all values marked Drop by Nothing

countKept :: forall t (f :: Type -> Type) a. Foldable t => t (Marked f a) -> Word Source #

Count how many elements will be kept

The element if it should be kept