Moduledata-checked-0.3Haskell98

Data.Checked.Strict

A version of Checked that requires client code to provide a non-bottom value of the property index type to use trust* functions.

newtypenewtype Checked p v

Wrapper-evidence for property p.

Instances1NFData

NFData v => NFData (Checked p v)Defined in data-checked-0.3 · Data.Checked.Strict

valuetrustThat :: p -> v -> Checked p v

Use when the property can be deduced without a runtime check. Note that p is evaluated to WHNF, so you can't use undefined.

valuetrustMap :: p -> (v -> v) -> Checked p v -> Checked p v

Apply a fuction that preserves the property to the checked value. Note that p is evaluated to WHNF, so you can't use undefined.

valuechecked :: Checked p v -> v

Unwrap the checked value.

classclass Property p v where

holds :: p -> v -> Bool
Test if the property holds for the given value. The first argument is supposed to be ignored.

valuemaybeHolds :: Property p v => p -> v -> Maybe v

Return Just v if p holds and Nothing overwise.

valuecheck :: Property p v => v -> Maybe (Checked p v)

Wrap the value if the property holds.

valuerelax :: Checked p v -> Checked p v

Rewrap a value into the less strict Checked type.