Documentation

A generic function that gives you full constructor coverage for a data type. Using this function as the Cover instance for a data type avoids the need to explicitly enumerate values that include coverage of all constructors.

Coverage is a list of values, implemented here with a newtype around a list of fake value generators. It's [FGen a] instead of FGen [a] because we don't want to have to evaluate the FGen monad to work with coverage lists.

A type class that generates a list of values giving full construcor coverage for data types. You can write your own instances by hand or you can use the default instance which calls gcover provided your data type has a Generic instance.

In some situations you don't have the ability to modify a data structure and need to define different Cover instances for different fields that have the same type. In these situations, instead of implementing the gcover logic by hand, you could alternatively use gcover to generate stock coverage values and then go back and replace the necessary fields with more appropriate generators. This bind-like operation provides an easy way to do that.

Convenience infix operator for bindCover.

instance Cover Foo where
  cover = gcover
    &>>= fooField %%~ (_ -> fakeFooField)