Safe Haskell | None |
---|---|
Language | Haskell2010 |
DataCon
Contents
- data DataCon
- data DataConRep
- = NoDataConRep
- | DCR {
- dcr_wrap_id :: Id
- dcr_boxer :: DataConBoxer
- dcr_arg_tys :: [Type]
- dcr_stricts :: [StrictnessMark]
- dcr_bangs :: [HsImplBang]
- data SrcStrictness
- data SrcUnpackedness
- data HsSrcBang = HsSrcBang (Maybe SourceText) SrcUnpackedness SrcStrictness
- data HsImplBang
- data StrictnessMark
- type ConTag = Int
- data EqSpec
- mkEqSpec :: TyVar -> Type -> EqSpec
- eqSpecTyVar :: EqSpec -> TyVar
- eqSpecType :: EqSpec -> Type
- eqSpecPair :: EqSpec -> (TyVar, Type)
- eqSpecPreds :: [EqSpec] -> ThetaType
- substEqSpec :: TCvSubst -> EqSpec -> EqSpec
- data FieldLbl a = FieldLabel {
- flLabel :: FieldLabelString
- flIsOverloaded :: Bool
- flSelector :: a
- type FieldLabel = FieldLbl Name
- type FieldLabelString = FastString
- mkDataCon :: Name -> Bool -> TyConRepName -> [HsSrcBang] -> [FieldLabel] -> [TyVar] -> [TyVar] -> [EqSpec] -> ThetaType -> [Type] -> Type -> TyCon -> ThetaType -> Id -> DataConRep -> DataCon
- buildAlgTyCon :: Name -> [TyVar] -> [Role] -> Maybe CType -> ThetaType -> AlgTyConRhs -> RecFlag -> Bool -> AlgTyConFlav -> TyCon
- fIRST_TAG :: ConTag
- dataConRepType :: DataCon -> Type
- dataConSig :: DataCon -> ([TyVar], ThetaType, [Type], Type)
- dataConInstSig :: DataCon -> [Type] -> ([TyVar], ThetaType, [Type])
- dataConFullSig :: DataCon -> ([TyVar], [TyVar], [EqSpec], ThetaType, [Type], Type)
- dataConName :: DataCon -> Name
- dataConIdentity :: DataCon -> [Word8]
- dataConTag :: DataCon -> ConTag
- dataConTyCon :: DataCon -> TyCon
- dataConOrigTyCon :: DataCon -> TyCon
- dataConUserType :: DataCon -> Type
- dataConUnivTyVars :: DataCon -> [TyVar]
- dataConExTyVars :: DataCon -> [TyVar]
- dataConAllTyVars :: DataCon -> [TyVar]
- dataConEqSpec :: DataCon -> [EqSpec]
- dataConTheta :: DataCon -> ThetaType
- dataConStupidTheta :: DataCon -> ThetaType
- dataConInstArgTys :: DataCon -> [Type] -> [Type]
- dataConOrigArgTys :: DataCon -> [Type]
- dataConOrigResTy :: DataCon -> Type
- dataConInstOrigArgTys :: DataCon -> [Type] -> [Type]
- dataConRepArgTys :: DataCon -> [Type]
- dataConFieldLabels :: DataCon -> [FieldLabel]
- dataConFieldType :: DataCon -> FieldLabelString -> Type
- dataConSrcBangs :: DataCon -> [HsSrcBang]
- dataConSourceArity :: DataCon -> Arity
- dataConRepArity :: DataCon -> Arity
- dataConRepRepArity :: DataCon -> RepArity
- dataConIsInfix :: DataCon -> Bool
- dataConWorkId :: DataCon -> Id
- dataConWrapId :: DataCon -> Id
- dataConWrapId_maybe :: DataCon -> Maybe Id
- dataConImplicitTyThings :: DataCon -> [TyThing]
- dataConRepStrictness :: DataCon -> [StrictnessMark]
- dataConImplBangs :: DataCon -> [HsImplBang]
- dataConBoxer :: DataCon -> Maybe DataConBoxer
- splitDataProductType_maybe :: Type -> Maybe (TyCon, [Type], DataCon, [Type])
- isNullarySrcDataCon :: DataCon -> Bool
- isNullaryRepDataCon :: DataCon -> Bool
- isTupleDataCon :: DataCon -> Bool
- isUnboxedTupleCon :: DataCon -> Bool
- isVanillaDataCon :: DataCon -> Bool
- classDataCon :: Class -> DataCon
- dataConCannotMatch :: [Type] -> DataCon -> Bool
- isBanged :: HsImplBang -> Bool
- isMarkedStrict :: StrictnessMark -> Bool
- eqHsBang :: HsImplBang -> HsImplBang -> Bool
- isSrcStrict :: SrcStrictness -> Bool
- isSrcUnpacked :: SrcUnpackedness -> Bool
- specialPromotedDc :: DataCon -> Bool
- isLegacyPromotableDataCon :: DataCon -> Bool
- isLegacyPromotableTyCon :: TyCon -> Bool
- promoteDataCon :: DataCon -> TyCon
Main data types
data DataCon
A data constructor
data DataConRep
Constructors
NoDataConRep | |
DCR | |
Fields
|
data SrcStrictness
What strictness annotation the user wrote
Constructors
SrcLazy | Lazy, ie '~' |
SrcStrict | Strict, ie |
NoSrcStrict | no strictness annotation |
data SrcUnpackedness
What unpackedness the user requested
Constructors
SrcUnpack | |
SrcNoUnpack | |
NoSrcUnpack | no unpack pragma |
data HsSrcBang
Bangs on data constructor arguments as the user wrote them in the source code.
(HsSrcBang _ SrcUnpack SrcLazy) and (HsSrcBang _ SrcUnpack NoSrcStrict) (without StrictData) makes no sense, we emit a warning (in checkValidDataCon) and treat it like (HsSrcBang _ NoSrcUnpack SrcLazy)
Constructors
HsSrcBang (Maybe SourceText) SrcUnpackedness SrcStrictness |
Instances
data HsImplBang
Bangs of data constructor arguments as generated by the compiler after consulting HsSrcBang, flags, etc.
Constructors
HsLazy | Lazy field |
HsStrict | Strict but not unpacked field |
HsUnpack (Maybe Coercion) | Strict and unpacked field co :: arg-ty ~ product-ty HsBang |
Instances
Type of the tags associated with each constructor possibility or superclass selector
Equality specs
data EqSpec
An EqSpec
is a tyvar/type pair representing an equality made in
rejigging a GADT constructor
Instances
eqSpecTyVar :: EqSpec -> TyVar
eqSpecType :: EqSpec -> Type
eqSpecPair :: EqSpec -> (TyVar, Type)
eqSpecPreds :: [EqSpec] -> ThetaType
substEqSpec :: TCvSubst -> EqSpec -> EqSpec
Substitute in an EqSpec
. Precondition: if the LHS of the EqSpec
is mapped in the substitution, it is mapped to a type variable, not
a full type.
Field labels
data FieldLbl a
Fields in an algebraic record type
Constructors
FieldLabel | |
Fields
|
type FieldLabel = FieldLbl Name
type FieldLabelString = FastString
Field labels are just represented as strings; they are not necessarily unique (even within a module)
Type construction
Arguments
:: Name | |
-> Bool | Is the constructor declared infix? |
-> TyConRepName | TyConRepName for the promoted TyCon |
-> [HsSrcBang] | Strictness/unpack annotations, from user |
-> [FieldLabel] | Field labels for the constructor, if it is a record, otherwise empty |
-> [TyVar] | Universally quantified type variables |
-> [TyVar] | Existentially quantified type variables |
-> [EqSpec] | GADT equalities |
-> ThetaType | Theta-type occuring before the arguments proper |
-> [Type] | Original argument types |
-> Type | Original result type |
-> TyCon | Representation type constructor |
-> ThetaType | The "stupid theta", context of the data
declaration e.g. |
-> Id | Worker Id |
-> DataConRep | Representation |
-> DataCon |
Build a new data constructor
Type deconstruction
dataConRepType :: DataCon -> Type
The representation type of the data constructor, i.e. the sort type that will represent values of this type at runtime
dataConSig :: DataCon -> ([TyVar], ThetaType, [Type], Type)
The "signature" of the DataCon
returns, in order:
1) The result of dataConAllTyVars
,
2) All the ThetaType
s relating to the DataCon
(coercion, dictionary, implicit
parameter - whatever)
3) The type arguments to the constructor
4) The original result type of the DataCon
dataConInstSig :: DataCon -> [Type] -> ([TyVar], ThetaType, [Type])
Instantantiate the universal tyvars of a data con, returning the instantiated existentials, constraints, and args
dataConFullSig :: DataCon -> ([TyVar], [TyVar], [EqSpec], ThetaType, [Type], Type)
The "full signature" of the DataCon
returns, in order:
1) The result of dataConUnivTyVars
2) The result of dataConExTyVars
3) The GADT equalities
4) The result of dataConDictTheta
5) The original argument types to the DataCon
(i.e. before
any change of the representation of the type)
6) The original result type of the DataCon
dataConName :: DataCon -> Name
dataConIdentity :: DataCon -> [Word8]
The string package:module.name
identifying a constructor, which is attached
to its info table and used by the GHCi debugger and the heap profiler
dataConTag :: DataCon -> ConTag
The tag used for ordering DataCon
s
dataConTyCon :: DataCon -> TyCon
The type constructor that we are building via this data constructor
dataConOrigTyCon :: DataCon -> TyCon
The original type constructor used in the definition of this data constructor. In case of a data family instance, that will be the family type constructor.
dataConUserType :: DataCon -> Type
The user-declared type of the data constructor in the nice-to-read form:
T :: forall a b. a -> b -> T [a]
rather than:
T :: forall a c. forall b. (c~[a]) => a -> b -> T c
NB: If the constructor is part of a data instance, the result type mentions the family tycon, not the internal one.
dataConUnivTyVars :: DataCon -> [TyVar]
The universally-quantified type variables of the constructor
dataConExTyVars :: DataCon -> [TyVar]
The existentially-quantified type variables of the constructor
dataConAllTyVars :: DataCon -> [TyVar]
Both the universal and existentiatial type variables of the constructor
dataConEqSpec :: DataCon -> [EqSpec]
Equalities derived from the result type of the data constructor, as written by the programmer in any GADT declaration. This includes *all* GADT-like equalities, including those written in by hand by the programmer.
dataConTheta :: DataCon -> ThetaType
The *full* constraints on the constructor type.
dataConStupidTheta :: DataCon -> ThetaType
The "stupid theta" of the DataCon
, such as data Eq a
in:
data Eq a => T a = ...
Arguments
:: DataCon | A datacon with no existentials or equality constraints However, it can have a dcTheta (notably it can be a class dictionary, with superclasses) |
-> [Type] | Instantiated at these types |
-> [Type] |
Finds the instantiated types of the arguments required to construct a DataCon
representation
NB: these INCLUDE any dictionary args
but EXCLUDE the data-declaration context, which is discarded
It's all post-flattening etc; this is a representation type
dataConOrigArgTys :: DataCon -> [Type]
Returns the argument types of the wrapper, excluding all dictionary arguments and without substituting for any type variables
dataConOrigResTy :: DataCon -> Type
dataConInstOrigArgTys :: DataCon -> [Type] -> [Type]
Returns just the instantiated value argument types of a DataCon
,
(excluding dictionary args)
dataConRepArgTys :: DataCon -> [Type]
Returns the arg types of the worker, including *all* evidence, after any flattening has been done and without substituting for any type variables
dataConFieldLabels :: DataCon -> [FieldLabel]
The labels for the fields of this particular DataCon
dataConFieldType :: DataCon -> FieldLabelString -> Type
Extract the type for any given labelled field of the DataCon
dataConSrcBangs :: DataCon -> [HsSrcBang]
Strictness/unpack annotations, from user; or, for imported
DataCons, from the interface file
The list is in one-to-one correspondence with the arity of the DataCon
dataConSourceArity :: DataCon -> Arity
Source-level arity of the data constructor
dataConRepArity :: DataCon -> Arity
Gives the number of actual fields in the representation of the data constructor. This may be more than appear in the source code; the extra ones are the existentially quantified dictionaries
dataConRepRepArity :: DataCon -> RepArity
The number of fields in the representation of the constructor AFTER taking into account the unpacking of any unboxed tuple fields
dataConIsInfix :: DataCon -> Bool
Should the DataCon
be presented infix?
dataConWorkId :: DataCon -> Id
dataConWrapId :: DataCon -> Id
Returns an Id which looks like the Haskell-source constructor by using
the wrapper if it exists (see dataConWrapId_maybe
) and failing over to
the worker (see dataConWorkId
)
dataConWrapId_maybe :: DataCon -> Maybe Id
Get the Id of the DataCon
wrapper: a function that wraps the "actual"
constructor so it has the type visible in the source program: c.f. dataConWorkId
.
Returns Nothing if there is no wrapper, which occurs for an algebraic data constructor
and also for a newtype (whose constructor is inlined compulsorily)
dataConImplicitTyThings :: DataCon -> [TyThing]
Find all the Id
s implicitly brought into scope by the data constructor. Currently,
the union of the dataConWorkId
and the dataConWrapId
dataConRepStrictness :: DataCon -> [StrictnessMark]
Give the demands on the arguments of a Core constructor application (Con dc args)
dataConImplBangs :: DataCon -> [HsImplBang]
dataConBoxer :: DataCon -> Maybe DataConBoxer
Extract the type constructor, type argument, data constructor and it's representation argument types from a type if it is a product type.
Precisely, we return Just
for any type that is all of:
- Concrete (i.e. constructors visible)
- Single-constructor
- Not existentially quantified
Whether the type is a data
type or a newtype
Predicates on DataCons
isNullarySrcDataCon :: DataCon -> Bool
Return whether there are any argument types for this DataCon
s original source type
isNullaryRepDataCon :: DataCon -> Bool
Return whether there are any argument types for this DataCon
s runtime representation type
isTupleDataCon :: DataCon -> Bool
isUnboxedTupleCon :: DataCon -> Bool
isVanillaDataCon :: DataCon -> Bool
Vanilla DataCon
s are those that are nice boring Haskell 98 constructors
classDataCon :: Class -> DataCon
dataConCannotMatch :: [Type] -> DataCon -> Bool
isBanged :: HsImplBang -> Bool
isMarkedStrict :: StrictnessMark -> Bool
eqHsBang :: HsImplBang -> HsImplBang -> Bool
Compare strictness annotations
isSrcStrict :: SrcStrictness -> Bool
isSrcUnpacked :: SrcUnpackedness -> Bool
specialPromotedDc :: DataCon -> Bool
Should this DataCon be allowed in a type even without -XDataKinds? Currently, only Lifted & Unlifted
isLegacyPromotableDataCon :: DataCon -> Bool
Was this datacon promotable before GHC 8.0? That is, is it promotable without -XTypeInType
isLegacyPromotableTyCon :: TyCon -> Bool
Was this tycon promotable before GHC 8.0? That is, is it promotable without -XTypeInType
Promotion related functions
promoteDataCon :: DataCon -> TyCon