Copyright	(c) Dong Han 2017-2020
License	BSD
Maintainer	winterland1989@gmail.com
Stability	experimental
Portability	non-portable
Safe Haskell	None
Language	Haskell2010

Z.Data.Generics.Utils

Description

This module provides a helper class to compute product size via Generic instance, e.g. This class is useful during JSON deserializing, to decide the array length used to store record KVs.

Synopsis

class KnownNat (PSize f) => ProductSize (f :: * -> *) where
- type PSize f :: Nat
productSize :: forall f. KnownNat (PSize f) => Proxy# f -> Int

Documentation

class KnownNat (PSize f) => ProductSize (f :: * -> *) Source #

type class for calculating product size.

Associated Types

type PSize f :: Nat Source #

Instances

Instances details

(KnownNat (PSize a + PSize b), ProductSize a, ProductSize b) => ProductSize (a :*: b) Source #
Instance details Defined in Z.Data.Generics.Utils Associated Types type PSize (a :*: b) :: Nat Source #
ProductSize (S1 s a) Source #
Instance details Defined in Z.Data.Generics.Utils Associated Types type PSize (S1 s a) :: Nat Source #

productSize :: forall f. KnownNat (PSize f) => Proxy# f -> Int Source #