Data.Vinyl.CoRec

Generalize algebraic sum types.

A CoRec constructor with better inference. If you have a label that should pick out a type from the list of types that index a CoRec, this function will help you more so than the raw CoRec data constructor.

Apply a function to a CoRec value. The function must accept any variant.

A Field of a Rec Identity is a CoRec Identity.

A function type constructor that takes its arguments in the reverse order.

Helper for writing a Show instance for CoRec. This lets us ask for a Show constraint on the type formed by applying a type constructor to a type index.

We can inject a a CoRec into a Rec where every field of the Rec is Nothing except for the one whose type corresponds to the type of the given CoRec variant.

Shorthand for applying coRecToRec with common functors.

Fold a field selection function over a Rec.

Apply a natural transformation to a variant.

Get a DictOnly from an RPureConstrained instance.

Like coRecMap, but the function mapped over the CoRec can have a constraint.

This can be used to pull effects out of a CoRec.

Fold a field selection function over a non-empty Rec.

Similar to First: find the first field that is not Nothing.

Similar to Last: find the last field that is not Nothing.

Apply methods from a type class to a CoRec. Intended for use with TypeApplications, e.g. onCoRec @Show show r

Apply a type class method to a Field. Intended for use with TypeApplications, e.g. onField @Show show r.

Compute a runtime Int index identifying the position of the variant held by a CoRec f ts in the type-level list ts.

If a CoRec is a variant of the requested type, return Just that value; otherwise return Nothing.

Like asA, but for any interpretation functor.

Pattern match on a CoRec by specifying handlers for each case. Note that the order of the Handlers has to match the type level list (t:ts).

>>> :{let testCoRec = Col (Identity False) :: CoRec Identity [Int, String, Bool] inmatch testCoRec $      (H $ \i -> "my Int is the successor of " ++ show (i - 1))   :& (H $ \s -> "my String is: " ++ s)   :& (H $ \b -> "my Bool is not: " ++ show (not b) ++ " thus it is " ++ show b)   :& RNil:}"my Bool is not: True thus it is False"

Helper for handling a variant of a CoRec: either the function is applied to the variant or the type of the CoRec is refined to reflect the fact that the variant is not compatible with the type of the would-be handler.

Handle a single variant of a CoRec: either the function is applied to the variant or the type of the CoRec is refined to reflect the fact that the variant is not compatible with the type of the would-be handler

Newtype around functions for a to b

'Handlers ts b', is essentially a list of functions, one for each type in ts. All functions produce a value of type b. Hence, 'Handlers ts b' would represent something like the type-level list: [t -> b | t in ts ]

A CoRec is either the first possible variant indicated by its type, or a CoRec that must be one of the remaining types.

A CoRec whose possible types are ts may be used at a type of CoRec whose possible types are t:ts.

A CoRec is either the first possible variant indicated by its type, or a CoRec that must be one of the remaining types. The safety is related to that of asASafe.

Like asA, but implemented more safely and typically slower.

Like asASafe, but for any interpretation functor.