Documentation

For each enum type we need 1) a list of all possible values 2) a way to serialise and 3) deserialise.

TODO: Update this comment to explain what a GraphQLEnum is, why you might want an instance, and any laws that apply to method relations.

Argument operator. Can only be used with Field.

Say we have a Company object that has a field that shows whether someone is an employee, e.g.

  type Company {
    hasEmployee(employeeName: String!): String!
  }

Then we might represent that as:

>>> type Company = Object "Company" '[] '[Argument "employeeName" Text :> Field "hasEmployee" Bool]

For multiple arguments, simply chain them together with :>, ending finally with Field. e.g.

  Argument "foo" String :> Argument "bar" Int :> Field "qux" Int

Specify a default value for a type in a GraphQL schema.

GraphQL schema can have default values in certain places. For example, arguments to fields can have default values. Because we cannot lift arbitrary values to the type level, we need some way of getting at those values. This typeclass provides the means.

To specify a default, implement this typeclass.

The default implementation is to say that there *is* no default for this type.