Language.PureScript.Environment

Documentation

data Environment

The Environment defines all values and types which are currently in scope:

Constructors

Environment

Fields

• names :: Map (Qualified Ident) (Type, NameKind, NameVisibility)

  Values currently in scope

• types :: Map (Qualified (ProperName TypeName)) (Kind, TypeKind)

  Type names currently in scope

• dataConstructors :: Map (Qualified (ProperName ConstructorName)) (DataDeclType, ProperName TypeName, Type, [Ident])

  Data constructors currently in scope, along with their associated type constructor name, argument types and return type.

• typeSynonyms :: Map (Qualified (ProperName TypeName)) ([(Text, Maybe Kind)], Type)

  Type synonyms currently in scope

• typeClassDictionaries :: Map (Maybe ModuleName) (Map (Qualified (ProperName ClassName)) (Map (Qualified Ident) NamedDict))

  Available type class dictionaries

• typeClasses :: Map (Qualified (ProperName ClassName)) TypeClassData

  Type classes

• kinds :: Set (Qualified (ProperName KindName))

  Kinds in scope

Instances

Show Environment

Methods

showsPrec :: Int -> Environment -> ShowS

show :: Environment -> String

showList :: [Environment] -> ShowS

data TypeClassData

Information about a type class

Constructors

TypeClassData

Fields

• typeClassArguments :: [(Text, Maybe Kind)]

  A list of type argument names, and their kinds, where kind annotations were provided.

• typeClassMembers :: [(Ident, Type)]

  A list of type class members and their types. Type arguments listed above are considered bound in these types.

• typeClassSuperclasses :: [Constraint]

  A list of superclasses of this type class. Type arguments listed above are considered bound in the types appearing in these constraints.

• typeClassDependencies :: [FunctionalDependency]

  A list of functional dependencies for the type arguments of this class.

• typeClassDeterminedArguments :: Set Int

  A set of indexes of type argument that are fully determined by other arguments via functional dependencies. This can be computed from both typeClassArguments and typeClassDependencies.

• typeClassCoveringSets :: Set (Set Int)

  A sets of arguments that can be used to infer all other arguments.

Instances

Show TypeClassData

Methods

showsPrec :: Int -> TypeClassData -> ShowS

show :: TypeClassData -> String

showList :: [TypeClassData] -> ShowS

data FunctionalDependency

A functional dependency indicates a relationship between two sets of type arguments in a class declaration.

Constructors

FunctionalDependency

Fields

• fdDeterminers :: [Int]

  the type arguments which determine the determined type arguments

• fdDetermined :: [Int]

  the determined type arguments

Instances

Show FunctionalDependency

Methods

showsPrec :: Int -> FunctionalDependency -> ShowS

show :: FunctionalDependency -> String

showList :: [FunctionalDependency] -> ShowS

ToJSON FunctionalDependency

Methods

toJSON :: FunctionalDependency -> Value

toEncoding :: FunctionalDependency -> Encoding

FromJSON FunctionalDependency

Methods

parseJSON :: Value -> Parser FunctionalDependency

initEnvironment :: Environment

The initial environment with no values and only the default javascript types defined

makeTypeClassData :: [(Text, Maybe Kind)] -> [(Ident, Type)] -> [Constraint] -> [FunctionalDependency] -> TypeClassData

A constructor for TypeClassData that computes which type class arguments are fully determined and argument covering sets. Fully determined means that this argument cannot be used when selecting a type class instance. A covering set is a minimal collection of arguments that can be used to find an instance and therefore determine all other type arguments.

An example of the difference between determined and fully determined would be with the class: ```class C a b c | a -> b, b -> a, b -> c``` In this case, a must differ when b differs, and vice versa - each is determined by the other. Both a and b can be used in selecting a type class instance. However, c cannot - it is fully determined by a and b.

Define a graph of type class arguments with edges being fundep determiners to determined. Each argument also has a self looping edge. An argument is fully determined if doesn't appear at the start of a path of strongly connected components. An argument is not fully determined otherwise.

The way we compute this is by saying: an argument X is fully determined if there are arguments that determine X that X does not determine. This is the same thing: everything X determines includes everything in its SCC, and everything determining X is either before it in an SCC path, or in the same SCC.

data NameVisibility

The visibility of a name in scope

Constructors

Undefined

The name is defined in the current binding group, but is not visible

Defined

The name is defined in the another binding group, or has been made visible by a function binder

Instances

Eq NameVisibility

Methods

(==) :: NameVisibility -> NameVisibility -> Bool

(/=) :: NameVisibility -> NameVisibility -> Bool

Show NameVisibility

Methods

showsPrec :: Int -> NameVisibility -> ShowS

show :: NameVisibility -> String

showList :: [NameVisibility] -> ShowS

data NameKind

A flag for whether a name is for an private or public value - only public values will be included in a generated externs file.

Constructors

Private

A private value introduced as an artifact of code generation (class instances, class member accessors, etc.)

Public

A public value for a module member or foreing import declaration

External

A name for member introduced by foreign import

Instances

Eq NameKind

Methods

(==) :: NameKind -> NameKind -> Bool

(/=) :: NameKind -> NameKind -> Bool

Show NameKind

Methods

showsPrec :: Int -> NameKind -> ShowS

show :: NameKind -> String

showList :: [NameKind] -> ShowS

data TypeKind

The kinds of a type

Constructors

DataType [(Text, Maybe Kind)] [(ProperName ConstructorName, [Type])]

Data type

TypeSynonym

Type synonym

ExternData

Foreign data

LocalTypeVariable

A local type variable

ScopedTypeVar

A scoped type variable

Instances

Eq TypeKind

Methods

(==) :: TypeKind -> TypeKind -> Bool

(/=) :: TypeKind -> TypeKind -> Bool

Show TypeKind

Methods

showsPrec :: Int -> TypeKind -> ShowS

show :: TypeKind -> String

showList :: [TypeKind] -> ShowS

ToJSON TypeKind

Methods

toJSON :: TypeKind -> Value

toEncoding :: TypeKind -> Encoding

FromJSON TypeKind

Methods

parseJSON :: Value -> Parser TypeKind

data DataDeclType

The type ('data' or 'newtype') of a data type declaration

Constructors

Data

A standard data constructor

Newtype

A newtype constructor

Instances

Eq DataDeclType

Methods

(==) :: DataDeclType -> DataDeclType -> Bool

(/=) :: DataDeclType -> DataDeclType -> Bool

Ord DataDeclType

Methods

compare :: DataDeclType -> DataDeclType -> Ordering

(<) :: DataDeclType -> DataDeclType -> Bool

(<=) :: DataDeclType -> DataDeclType -> Bool

(>) :: DataDeclType -> DataDeclType -> Bool

(>=) :: DataDeclType -> DataDeclType -> Bool

max :: DataDeclType -> DataDeclType -> DataDeclType

min :: DataDeclType -> DataDeclType -> DataDeclType

Show DataDeclType

Methods

showsPrec :: Int -> DataDeclType -> ShowS

show :: DataDeclType -> String

showList :: [DataDeclType] -> ShowS

ToJSON DataDeclType

Methods

toJSON :: DataDeclType -> Value

toEncoding :: DataDeclType -> Encoding

FromJSON DataDeclType

Methods

parseJSON :: Value -> Parser DataDeclType

showDataDeclType :: DataDeclType -> Text

primName :: Text -> Qualified (ProperName a)

Construct a ProperName in the Prim module

primKind :: Text -> Kind

kindType :: Kind

Kinds in prim

kindEffect :: Kind

kindSymbol :: Kind

primTy :: Text -> Type

Construct a type in the Prim module

tyFunction :: Type

Type constructor for functions

tyString :: Type

Type constructor for strings

tyChar :: Type

Type constructor for strings

tyNumber :: Type

Type constructor for numbers

tyInt :: Type

Type constructor for integers

tyBoolean :: Type

Type constructor for booleans

tyArray :: Type

Type constructor for arrays

tyRecord :: Type

Type constructor for records

isObject :: Type -> Bool

Check whether a type is a record

isFunction :: Type -> Bool

Check whether a type is a function

isTypeOrApplied :: Type -> Type -> Bool

function :: Type -> Type -> Type

Smart constructor for function types

primKinds :: Set (Qualified (ProperName KindName))

The primitive kinds

primTypes :: Map (Qualified (ProperName TypeName)) (Kind, TypeKind)

The primitive types in the external javascript environment with their associated kinds. There are also pseudo Fail and Partial types that correspond to the classes with the same names.

primClasses :: Map (Qualified (ProperName ClassName)) TypeClassData

The primitive class map. This just contains the Fail and Partial classes. Partial is used as a kind of magic constraint for partial functions. Fail is used for user-defined type errors.

lookupConstructor :: Environment -> Qualified (ProperName ConstructorName) -> (DataDeclType, ProperName TypeName, Type, [Ident])

Finds information about data constructors from the current environment.

isNewtypeConstructor :: Environment -> Qualified (ProperName ConstructorName) -> Bool

Checks whether a data constructor is for a newtype.

lookupValue :: Environment -> Qualified Ident -> Maybe (Type, NameKind, NameVisibility)

Finds information about values from the current environment.