Copyright	(c) Andrey Mulik 2020
License	BSD-style
Maintainer	work.a.mulik@gmail.com
Portability	non-portable (GHC extensions)
Safe Haskell	Trustworthy
Language	Haskell2010

SDP.Nullable

Contents

Nullable

Description

SDP.Nullable provides Nullable - class of types with empty values.

Synopsis

class Nullable e where
- lzero :: e
- isNull :: e -> Bool
pattern NULL :: Nullable e => e

Nullable

class Nullable e where Source #

Nullable is class of types which value may be empty.

Methods

lzero :: e Source #

Empty value.

isNull :: e -> Bool Source #

Is value empty?

Instances

Instances details

Nullable [e] Source #
Instance details Defined in SDP.Nullable Methods lzero :: [e] Source # isNull :: [e] -> Bool Source #
Nullable (Maybe e) Source #
Instance details Defined in SDP.Nullable Methods lzero :: Maybe e Source # isNull :: Maybe e -> Bool Source #
Nullable (StablePtr e) Source #
Instance details Defined in SDP.Nullable Methods lzero :: StablePtr e Source # isNull :: StablePtr e -> Bool Source #
Nullable (Ptr e) Source #
Instance details Defined in SDP.Nullable Methods lzero :: Ptr e Source # isNull :: Ptr e -> Bool Source #
Nullable (ForeignPtr e) Source #
Instance details Defined in SDP.Nullable Methods lzero :: ForeignPtr e Source # isNull :: ForeignPtr e -> Bool Source #
Nullable (SBytes# e) Source #
Instance details Defined in SDP.Prim.SBytes Methods lzero :: SBytes# e Source # isNull :: SBytes# e -> Bool Source #
Nullable (SArray# e) Source #
Instance details Defined in SDP.Prim.SArray Methods lzero :: SArray# e Source # isNull :: SArray# e -> Bool Source #
Nullable (TArray# e) Source #
Instance details Defined in SDP.Prim.TArray Methods lzero :: TArray# e Source # isNull :: TArray# e -> Bool Source #
Index i => Nullable (i, i) Source #
Instance details Defined in SDP.Index Methods lzero :: (i, i) Source # isNull :: (i, i) -> Bool Source #
Nullable (AnyChunks rep e) Source #
Instance details Defined in SDP.Templates.AnyChunks Methods lzero :: AnyChunks rep e Source # isNull :: AnyChunks rep e -> Bool Source #
(Index i, Bordered (rep e) Int, Nullable (rep e)) => Nullable (AnyBorder rep i e) Source #
Instance details Defined in SDP.Templates.AnyBorder Methods lzero :: AnyBorder rep i e Source # isNull :: AnyBorder rep i e -> Bool Source #

pattern NULL :: Nullable e => e Source #

Originally defined in sdp-ctypes (now sdp-foreign), same as Z now.