Data.TypeHash

Produce a hash for a type that is unique for that type. The hash takes both actual type names and type structure into account.

The purpose of the hash of a type is to be able to store the type of a persisted value together with the value. By comparing the type hash of a persisted value and the expected value we can know if the persistened value is of the correct type.

The current implementation is not really a hash, but a string representation of the type structure.

Documentation

newtype TypeHash

The type of a hashed type.

Constructors

TypeHash String

Instances

Eq TypeHash

Data TypeHash

Ord TypeHash

Read TypeHash

Show TypeHash

Typeable TypeHash

typeHash :: Data a => a -> TypeHash

Turn the type of the value into a type hash.

data Type

Constructors

Name

Fields

typeName :: String

Data

Fields

typeName :: String

constrs :: [(String, [Field])]

Instances

Eq Type

Ord Type

Show Type

type Field = (String, Type)

gType :: Data a => [String] -> a -> Type

gConstr :: Data a => [String] -> a -> Constr -> (String, [Field])

fullTypeOf :: Data a => a -> TypeRep