ghc-7.10.2: The GHC API

Safe HaskellNone
LanguageHaskell2010

Id

Contents

Description

GHC uses several kinds of name internally:

Synopsis

The main types

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 
Outputable Var 
Uniquable Var 
NamedThing Var 
type PostRn Id ty = ty 
type PostTc Id ty = ty 

type Id = Var

isId :: Var -> Bool

Simple construction

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

For an explanation of global vs. local Ids, see Var

mkVanillaGlobal :: Name -> Type -> Id

Make a global Id without any extra information at all

mkVanillaGlobalWithInfo :: Name -> Type -> IdInfo -> Id

Make a global Id with no global information but some generic IdInfo

mkLocalId :: Name -> Type -> Id

For an explanation of global vs. local Ids, see Var

mkExportedLocalId :: IdDetails -> Name -> Type -> Id

Create a local Id that is marked as exported. This prevents things attached to it from being removed as dead code. See Note [Exported LocalIds]

mkSysLocal :: FastString -> Unique -> Type -> Id

Create a system local Id. These are local Ids (see Var) that are created by the compiler out of thin air

mkUserLocal :: OccName -> Unique -> Type -> SrcSpan -> Id

Create a user local Id. These are local Ids (see Var) with a name and location that the user might recognize

mkTemplateLocals :: [Type] -> [Id]

Create a template local for a series of types

mkTemplateLocalsNum :: Int -> [Type] -> [Id]

Create a template local for a series of type, but start from a specified template local

mkTemplateLocal :: Int -> Type -> Id

Create a template local: a family of system local Ids in bijection with Ints, typically used in unfoldings

mkWorkerId :: Unique -> Id -> Type -> Id

Workers get local names. CoreTidy will externalise these if necessary

Taking an Id apart

idName :: Id -> Name

idType :: Id -> Kind

recordSelectorFieldLabel :: Id -> (TyCon, FieldLabel)

If the Id is that for a record selector, extract the sel_tycon and label. Panic otherwise

Modifying an Id

setIdName :: Id -> Name -> Id

setIdType :: Id -> Type -> Id

Not only does this set the Id Type, it also evaluates the type to try and reduce space usage

globaliseId :: Id -> Id

If it's a local, make it global

transferPolyIdInfo :: Id -> [Var] -> Id -> Id

Predicates on Ids

isImplicitId :: Id -> Bool

isImplicitId tells whether an Ids info is implied by other declarations, so we don't need to put its signature in an interface file, even if it's mentioned in some other interface unfolding.

isStrictId :: Id -> Bool

This predicate says whether the Id has a strict demand placed on it or has a type such that it can always be evaluated strictly (i.e an unlifted type, as of GHC 7.6). We need to check separately whether the Id has a so-called "strict type" because if the demand for the given id hasn't been computed yet but id has a strict type, we still want isStrictId id to be True.

isExportedId :: Var -> Bool

isExportedIdVar means "don't throw this away"

idDataCon :: Id -> DataCon

Get from either the worker or the wrapper Id to the DataCon. Currently used only in the desugarer.

INVARIANT: idDataCon (dataConWrapId d) = d: remember, dataConWrapId can return either the wrapper or the worker

isBottomingId :: Id -> Bool

Returns true if an application to n args would diverge

hasNoBinding :: Id -> Bool

Returns True of an Id which may not have a binding, even though it is defined in this module.

Evidence variables

type DictId = EvId

Inline pragma stuff

setInlinePragma :: Id -> InlinePragma -> Id infixl 1

One-shot lambdas

isOneShotBndr :: Var -> Bool

Returns whether the lambda associated with the Id is certainly applied at most once This one is the "business end", called externally. It works on type variables as well as Ids, returning True Its main purpose is to encapsulate the Horrible State Hack

isOneShotLambda :: Id -> Bool

Returns whether the lambda associated with the Id is certainly applied at most once. You probably want to use isOneShotBndr instead

setIdOneShotInfo :: Id -> OneShotInfo -> Id infixl 1

stateHackOneShot :: OneShotInfo

Should we apply the state hack to values of this Type?

Reading IdInfo fields

idCafInfo :: Id -> CafInfo infixl 1

Writing IdInfo fields

setIdUnfolding :: Id -> Unfolding -> Id infixl 1

setIdArity :: Id -> Arity -> Id infixl 1

setIdCallArity :: Id -> Arity -> Id infixl 1

setIdSpecialisation :: Id -> SpecInfo -> Id infixl 1

setIdOccInfo :: Id -> OccInfo -> Id infixl 1

setIdDemandInfo :: Id -> Demand -> Id infixl 1

setIdStrictness :: Id -> StrictSig -> Id infixl 1