ghc-9.10.0.20240426: The GHC API
Safe HaskellNone
LanguageGHC2021

GHC.Core.Multiplicity

Description

This module defines the semi-ring of multiplicities, and associated functions. Multiplicities annotate arrow types to indicate the linearity of the arrow (in the sense of linear types).

Mult is a type synonym for Type, used only when its kind is Multiplicity. To simplify dealing with multiplicities, functions such as mkMultMul perform simplifications such as Many * x = Many on the fly.

Synopsis

Documentation

type Mult = Type Source #

Mult is a type alias for Type.

Mult must contain Type because multiplicity variables are mere type variables (of kind Multiplicity) in Haskell. So the simplest implementation is to make Mult be Type.

Multiplicities can be formed with: - One: GHC.Types.One (= oneDataCon) - Many: GHC.Types.Many (= manyDataCon) - Multiplication: GHC.Types.MultMul (= multMulTyCon)

So that Mult feels a bit more structured, we provide pattern synonyms and smart constructors for these.

pattern OneTy :: Mult Source #

pattern ManyTy :: Mult Source #

mkMultSup :: Mult -> Mult -> Mult Source #

mkMultSup w1 w2 returns a multiplicity such that mkMultSup w1 w2 >= w1 and mkMultSup w1 w2 >= w2. See Note [Overapproximating multiplicities].

data Scaled a Source #

A shorthand for data with an attached Mult element (the multiplicity).

Constructors

Scaled !Mult a 

Instances

Instances details
Outputable a => Outputable (Scaled a) Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

ppr :: Scaled a -> SDoc Source #

Data a => Data (Scaled a) Source # 
Instance details

Defined in GHC.Core.TyCo.Rep

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Scaled a -> c (Scaled a) #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Scaled a) #

toConstr :: Scaled a -> Constr #

dataTypeOf :: Scaled a -> DataType #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Scaled a)) #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Scaled a)) #

gmapT :: (forall b. Data b => b -> b) -> Scaled a -> Scaled a #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Scaled a -> r #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Scaled a -> r #

gmapQ :: (forall d. Data d => d -> u) -> Scaled a -> [u] #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Scaled a -> u #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Scaled a -> m (Scaled a) #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Scaled a -> m (Scaled a) #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Scaled a -> m (Scaled a) #

unrestricted :: a -> Scaled a Source #

Scale a payload by Many

linear :: a -> Scaled a Source #

Scale a payload by One

tymult :: a -> Scaled a Source #

Scale a payload by Many; used for type arguments in core

mkScaled :: Mult -> a -> Scaled a Source #

scaledSet :: Scaled a -> b -> Scaled b Source #

data IsSubmult Source #

Constructors

Submult 
Unknown 

Instances

Instances details
Outputable IsSubmult Source # 
Instance details

Defined in GHC.Core.Multiplicity

Methods

ppr :: IsSubmult -> SDoc Source #

Show IsSubmult Source # 
Instance details

Defined in GHC.Core.Multiplicity

Eq IsSubmult Source # 
Instance details

Defined in GHC.Core.Multiplicity

submult :: Mult -> Mult -> IsSubmult Source #

submult w1 w2 check whether a value of multiplicity w1 is allowed where a value of multiplicity w2 is expected. This is a partial order.

mapScaledType :: (Type -> Type) -> Scaled Type -> Scaled Type Source #

Apply a function to both the Mult and the Type in a 'Scaled Type'