Copyright | (C) 2017 Csongor Kiss |
---|---|
License | BSD3 |
Maintainer | Csongor Kiss <kiss.csongor.kiss@gmail.com> |
Stability | experimental |
Portability | non-portable |
Safe Haskell | Safe |
Language | Haskell2010 |
Records.Generic
Description
Magic record operations using Generics
These classes need not be instantiated manually, as GHC can automatically
prove valid instances via Generics. Only the Generic
class needs to
be derived (see examples).
Subtype relationship
class Subtype sub sup where Source #
Structural subtype relationship
module Test where import GHC.Generics import Record.Generic data Human = Human { name :: String , age :: Int , address :: String } deriving (Generic, Show) data Animal = Animal { name :: String , age :: Int } deriving (Generic, Show) human :: Human human = Human "Tunyasz" 50 "London"
>>>
human
Human {name = "Tunyasz", age = 50, address = "London"}
>>>
upcast human :: Animal
Animal {name = "Tunyasz", age = 50}
Minimal complete definition
Magic lens
class HasField field a s | s field -> a where Source #
Records that have a field with a given name.
Minimal complete definition
Methods
Lens focusing on a field with a given name. Compatible with the lens package.
type Lens' s a = forall f. Functor f => (a -> f a) -> s -> f s
>>>
human & label @"name" .~ "Tamas"
Human {name = "Tamas", age = 50, address = "London"}