Var

Contents

The main data type and synonyms
- Taking Vars apart
- Modifying Vars
- Constructing, taking apart, modifying Ids
- Predicates
- Constructing TyVars
- Taking TyVars apart
- Modifying TyVars

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

Synopsis

The main data type and synonyms

data Var Source

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 Source

type CoVar = Id Source

type TyCoVar = TyVar Source

type Id = Var Source

type DictId = EvId Source

type DFunId = Id Source

type EvVar = Var Source

type EvId = Id Source

type IpId = EvId Source

Taking `Var`s apart

varName :: Var -> Name Source

varUnique :: Var -> Unique Source

varType :: Var -> Kind Source

Modifying `Var`s

setVarName :: Var -> Name -> Var Source

setVarUnique :: Var -> Unique -> Var Source

setVarType :: Id -> Type -> Id Source

Constructing, taking apart, modifying `Id`s

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

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

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

Exported Vars will not be removed as dead code

mkCoVar :: Name -> Type -> CoVar Source

idInfo :: Id -> IdInfo Source

idDetails :: Id -> IdDetails Source

lazySetIdInfo :: Id -> IdInfo -> Var Source

setIdDetails :: Id -> IdDetails -> Id Source

globaliseId :: Id -> Id Source

If it's a local, make it global

setIdExported :: Id -> Id Source

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

setIdNotExported :: Id -> Id Source

We can only do this to LocalIds

Predicates

isId :: Var -> Bool Source

isTyVar :: Var -> Bool Source

isTcTyVar :: Var -> Bool Source

isLocalVar :: Var -> Bool Source

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

isLocalId :: Var -> Bool Source

isGlobalId :: Var -> Bool Source

isExportedId :: Var -> Bool Source

isExportedIdVar means "don't throw this away"

mustHaveLocalBinding :: Var -> Bool Source

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