Safe Haskell	Safe-Inferred
Language	Haskell2010

Glam.Rules.Type

Description

The rules for checking types.

Synopsis

data TVarBinding
- = Syn [TVar] Type
- | Self {
  - _guardedness :: Guardedness
  - arguments :: Maybe [TVar]
  }
- | Bound
guardedness :: Traversal' TVarBinding Guardedness
type TEnvironment = Map TVar TVarBinding
type MonadCheckType m = (MonadReader TEnvironment m, MonadError String m)
guard :: Guardedness -> Guardedness
checkType :: MonadCheckType m => Type -> m (Type, First TVar)
checkPolytype :: MonadCheckType m => Polytype -> m Polytype
checkTypeSynonym :: MonadCheckType m => TVar -> [TVar] -> Type -> m Type

Documentation

data TVarBinding Source #

Things a type variable can refer to

Constructors

Syn [TVar] Type	A type synonym (with a list of arguments)
Self	A fixed point
Fields _guardedness :: Guardedness arguments :: Maybe [TVar] If this is the type synonym we're defining, contains its arguments
Bound	Anything else

guardedness :: Traversal' TVarBinding Guardedness Source #

type TEnvironment = Map TVar TVarBinding Source #

type MonadCheckType m = (MonadReader TEnvironment m, MonadError String m) Source #

guard :: Guardedness -> Guardedness Source #

Going under a ▸

checkType :: MonadCheckType m => Type -> m (Type, First TVar) Source #

Check that a type is well-formed and expand type synonyms. This handles desugaring recursive uses of type synonyms to fixed points: if the current type synonym is used (and applied to the same arguments), the second return value contains the fixed point variable to abstract over.

checkPolytype :: MonadCheckType m => Polytype -> m Polytype Source #

Check a polytype

checkTypeSynonym :: MonadCheckType m => TVar -> [TVar] -> Type -> m Type Source #

Check a type synonym definition