Implement a Query function that returns an indication of the correct type of Item. Eg for a Num instance, Query could return either the function to use to get the correct value or simply return the discriminator so the client can determine the correct helper function to use.
Implement a Query function that returns an indication of the correct type of Item. Eg for a Num instance, Query could return either the function to use to get the correct value or simply return the discriminator so the client can determine the correct helper function to use.