Documentation

A more expressive sum-type than just a list. This can be useful in situations where a body (request or response) may have several interpretations.

For example, the UVerb combinator lets us represent an endpoint that may return one of several types: hence the _routeResponseType field needs to be able to contain several TypeReps as a disjunction.

On the other hand, if multiple ReqBody's are chained together with :>, the resulting type's HasServer instance would try to parse the request body as all of the relevant types. In this case the _routeRequestBody field needs to be able to contain several TypeReps as a conjunction.

Convert a Body to a list of TypeReps. Inverse of listToBody.

Convert a list of TypeReps to a Body. Inverse of listToBody.

This maintains the invariant that the argument of ManyTypes has to be of length > 1.

This class does 2 things:

• It lets us get a term-level list of TypeReps from a type-level list of types, all of which have Typeable instances.
• More impressively, its instances enforce that typeReps will only type-check for type-level lists of length 2 or more. This is because AllTypeable will only ever be used by manyTypes (and its aliases), which is the only way to construct a ManyTypes and thus lets us enforce the invariant that ManyTypes will always have more than 1 argument. This lets us make sure that there's only ever one way to represent a list of TypeReps using Body.

Of course, someone might import this Internal module and define a Typeable a => AllTypeable '[a] instance. Don't do that.