ghc-7.0.4: The GHC API

Var

Contents

- The main data type and synonyms
  - Taking `Var`s apart
  - Modifying `Var`s
  - Constructing, taking apart, modifying `Id`s
  - Predicates
  - Constructing `TyVar`s
  - Taking `TyVar`s apart
  - Modifying `TyVar`s
  - Constructing `CoVar`s
  - Taking `CoVar`s apart
  - Modifying `CoVar`s

Description

GHC uses several kinds of name internally:

- `OccName.OccName`: see OccName
- `RdrName.RdrName`: see RdrName
- `Name`: see Name
- `Id.Id`: see Id
- `Var` is a synonym for the `Id.Id` type but it may additionally potentially contain type variables, which have a `Kind` rather than a `Type` and only contain some extra details during typechecking. These `Var` names may either be global or local, see Var

Global `Id`s and `Var`s are those that are imported or correspond to a data constructor, primitive operation, or record selectors. Local `Id`s and `Var`s are those bound within an expression (e.g. by a lambda) or at the top level of the module being compiled.

Synopsis

- data Var
- type TyVar = Var
- type CoVar = TyVar
- type Id = Var
- type DictId = EvId
- type DFunId = Id
- type EvVar = Var
- type EvId = Id
- type IpId = EvId
- varName :: Var -> Name
- varUnique :: Var -> Unique
- varType :: Var -> Kind
- setVarName :: Var -> Name -> Var
- setVarUnique :: Var -> Unique -> Var
- setVarType :: Id -> Type -> Id
- mkGlobalVar :: IdDetails -> Name -> Type -> IdInfo -> Id
- mkLocalVar :: IdDetails -> Name -> Type -> IdInfo -> Id
- mkExportedLocalVar :: IdDetails -> Name -> Type -> IdInfo -> Id
- idInfo :: Id -> IdInfo
- idDetails :: Id -> IdDetails
- lazySetIdInfo :: Id -> IdInfo -> Var
- setIdDetails :: Id -> IdDetails -> Id
- globaliseId :: Id -> Id
- setIdExported :: Id -> Id
- setIdNotExported :: Id -> Id
- isCoVar :: Var -> Bool
- isId :: Var -> Bool
- isTyCoVar :: Var -> Bool
- isTyVar :: Var -> Bool
- isTcTyVar :: Var -> Bool
- isLocalVar :: Var -> Bool
- isLocalId :: Var -> Bool
- isGlobalId :: Var -> Bool
- isExportedId :: Var -> Bool
- mustHaveLocalBinding :: Var -> Bool
- mkTyVar :: Name -> Kind -> TyVar
- mkTcTyVar :: Name -> Kind -> TcTyVarDetails -> TyVar
- mkWildCoVar :: Kind -> TyVar
- tyVarName :: TyVar -> Name
- tyVarKind :: TyVar -> Kind
- tcTyVarDetails :: TyVar -> TcTyVarDetails
- setTcTyVarDetails :: TyVar -> TcTyVarDetails -> TyVar
- setTyVarName :: TyVar -> Name -> TyVar
- setTyVarUnique :: TyVar -> Unique -> TyVar
- setTyVarKind :: TyVar -> Kind -> TyVar
- mkCoVar :: Name -> Kind -> CoVar
- coVarName :: CoVar -> Name
- setCoVarUnique :: CoVar -> Unique -> CoVar
- setCoVarName :: CoVar -> Name -> CoVar

# The main data type and synonyms

data Var

Essentially a typed `Name`, that may also contain some additional information about the `Var` and it's use sites.

Instances

Eq Var |
Data Var |
Ord Var |
Show Var |
Typeable Var |
OutputableBndr Var |
Outputable Var |
Uniquable Var |
NamedThing Var |

type TyVar = Var

type CoVar = TyVar

type Id = Var

type DictId = EvId

type DFunId = Id

type EvVar = Var

type EvId = Id

type IpId = EvId

## Taking `Var`s apart

varName :: Var -> Name

varUnique :: Var -> Unique

varType :: Var -> Kind

## Modifying `Var`s

setVarName :: Var -> Name -> Var

setVarUnique :: Var -> Unique -> Var

setVarType :: Id -> Type -> Id

## Constructing, taking apart, modifying `Id`s

mkGlobalVar :: IdDetails -> Name -> Type -> IdInfo -> Id

mkLocalVar :: IdDetails -> Name -> Type -> IdInfo -> Id

mkExportedLocalVar :: IdDetails -> Name -> Type -> IdInfo -> Id

Exported `Var`s will not be removed as dead code

idInfo :: Id -> IdInfo

idDetails :: Id -> IdDetails

lazySetIdInfo :: Id -> IdInfo -> Var

setIdDetails :: Id -> IdDetails -> Id

globaliseId :: Id -> Id

If it's a local, make it global

setIdExported :: Id -> Id

Exports the given local `Id`. Can also be called on global `Id`s, such as data constructors and class operations, which are born as global `Id`s and automatically exported

setIdNotExported :: Id -> Id

We can only do this to LocalIds

## Predicates

isCoVar :: Var -> Bool

isId :: Var -> Bool

isTyCoVar :: Var -> Bool

isTyVar :: Var -> Bool

isTcTyVar :: Var -> Bool

isLocalVar :: Var -> Bool

`isLocalVar` returns `True` for type variables as well as local `Id`s These are the variables that we need to pay attention to when finding free variables, or doing dependency analysis.

isLocalId :: Var -> Bool

isGlobalId :: Var -> Bool

isExportedId :: Var -> Bool

`isExportedIdVar` means "don't throw this away"

mustHaveLocalBinding :: Var -> Bool

`mustHaveLocalBinding` returns `True` of `Id`s and `TyVar`s that must have a binding in this module. The converse is not quite right: there are some global `Id`s that must have bindings, such as record selectors. But that doesn't matter, because it's only used for assertions

## Constructing `TyVar`s

mkTyVar :: Name -> Kind -> TyVar

mkTcTyVar :: Name -> Kind -> TcTyVarDetails -> TyVar

mkWildCoVar :: Kind -> TyVar

Create a type variable that is never referred to, so its unique doesn't matter

## Taking `TyVar`s apart

tyVarName :: TyVar -> Name

tyVarKind :: TyVar -> Kind

tcTyVarDetails :: TyVar -> TcTyVarDetails

setTcTyVarDetails :: TyVar -> TcTyVarDetails -> TyVar

## Modifying `TyVar`s

setTyVarName :: TyVar -> Name -> TyVar

setTyVarUnique :: TyVar -> Unique -> TyVar

setTyVarKind :: TyVar -> Kind -> TyVar

## Constructing `CoVar`s

mkCoVar :: Name -> Kind -> CoVar

## Taking `CoVar`s apart

coVarName :: CoVar -> Name

## Modifying `CoVar`s

setCoVarUnique :: CoVar -> Unique -> CoVar

setCoVarName :: CoVar -> Name -> CoVar