%
\section[HsDecls]{Abstract syntax: global declarations}
-Definitions for: @TyDecl@ and @ConDecl@, @ClassDecl@,
+Definitions for: @TyDecl@ and @oCnDecl@, @ClassDecl@,
@InstDecl@, @DefaultDecl@ and @ForeignDecl@.
\begin{code}
ConDecl(..), ConDetails(..),
BangType(..), getBangType,
DeprecDecl(..), DeprecTxt,
- hsDeclName, instDeclName, tyClDeclName, tyClDeclNames,
+ hsDeclName, instDeclName, tyClDeclName, tyClDeclNames, tyClDeclSysNames,
isClassDecl, isSynDecl, isDataDecl, isIfaceSigDecl, countTyClDecls,
mkClassDeclSysNames, isIfaceRuleDecl, ifaceRuleDeclName,
- getClassDeclSysNames
+ getClassDeclSysNames, conDetailsTys
) where
#include "HsVersions.h"
import CallConv ( CallConv, pprCallConv )
-- others:
+import Name ( NamedThing )
import FunDeps ( pprFundeps )
import Class ( FunDep, DefMeth(..) )
import CStrings ( CLabelString, pprCLabelString )
\begin{code}
#ifdef DEBUG
-hsDeclName :: (Outputable name, Outputable pat)
+hsDeclName :: (NamedThing name, Outputable name, Outputable pat)
=> HsDecl name pat -> name
#endif
hsDeclName (TyClD decl) = tyClDeclName decl
\end{code}
\begin{code}
-instance (Outputable name, Outputable pat)
+instance (NamedThing name, Outputable name, Outputable pat)
=> Outputable (HsDecl name pat) where
ppr (TyClD dcl) = ppr dcl
ppr (DeprecD dd) = ppr dd
\end{code}
-\begin{code}
-instance Ord name => Eq (HsDecl name pat) where
- -- Used only when comparing interfaces,
- -- at which time only signature and type/class decls
- (TyClD d1) == (TyClD d2) = d1 == d2
- _ == _ = False
-\end{code}
-
%************************************************************************
%* *
%* *
%************************************************************************
-Type and class declarations carry 'implicit names'. In particular:
+ --------------------------------
+ THE NAMING STORY
+ --------------------------------
+
+Here is the story about the implicit names that go with type, class, and instance
+decls. It's a bit tricky, so pay attention!
-Type A.
-~~~~~~~
+"Implicit" (or "system") binders
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Each data type decl defines
a worker name for each constructor
to-T and from-T convertors
Plan of attack:
- Make up their occurrence names immediately
+ This is done in RdrHsSyn.mkClassDecl, mkTyDecl, mkConDecl
- Ensure they "point to" the parent data/class decl
when loading that decl from an interface file
+ (See RnHiFiles.getTyClDeclSysNames)
- When renaming the decl look them up in the name cache,
ensure correct module and provenance is set
-Type B: Default methods and dictionary functions
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Have their own binding in an interface file.
-
-Default methods : occurrence name is derived uniquely from the class decl.
-Dict functions : occurrence name is derived from the instance decl, plus a unique number.
+Default methods
+~~~~~~~~~~~~~~~
+ - Occurrence name is derived uniquely from the method name
+ E.g. $dmmax
+
+ - If there is a default method name at all, it's recorded in
+ the ClassOpSig (in HsBinds), in the DefMeth field.
+ (DefMeth is defined in Class.lhs)
+
+Source-code class decls and interface-code class decls are treated subtly
+differently, which has given me a great deal of confusion over the years.
+Here's the deal. (We distinguish the two cases because source-code decls
+have (Just binds) in the tcdMeths field, whereas interface decls have Nothing.
+
+In *source-code* class declarations:
+ - When parsing, every ClassOpSig gets a DefMeth with a suitable RdrName
+ This is done by RdrHsSyn.mkClassOpSigDM
+
+ - The renamer renames it to a Name
+
+ - During typechecking, we generate a binding for each $dm for
+ which there's a programmer-supplied default method:
+ class Foo a where
+ op1 :: <type>
+ op2 :: <type>
+ op1 = ...
+ We generate a binding for $dmop1 but not for $dmop2.
+ The Class for Foo has a NoDefMeth for op2 and a DefMeth for op1.
+ The Name for $dmop2 is simply discarded.
+
+In *interface-file* class declarations:
+ - When parsing, we see if there's an explicit programmer-supplied default method
+ because there's an '=' sign to indicate it:
+ class Foo a where
+ op1 = :: <type> -- NB the '='
+ op2 :: <type>
+ We use this info to generate a DefMeth with a suitable RdrName for op1,
+ and a NoDefMeth for op2
+ - The interface file has a separate definition for $dmop1, with unfolding etc.
+ - The renamer renames it to a Name.
+ - The renamer treats $dmop1 as a free variable of the declaration, so that
+ the binding for $dmop1 will be sucked in. (See RnHsSyn.tyClDeclFVs)
+ This doesn't happen for source code class decls, because they *bind* the default method.
+
+Dictionary functions
+~~~~~~~~~~~~~~~~~~~~
+Each instance declaration gives rise to one dictionary function binding.
+
+The type checker makes up new source-code instance declarations
+(e.g. from 'deriving' or generic default methods --- see
+TcInstDcls.tcInstDecls1). So we can't generate the names for
+dictionary functions in advance (we don't know how many we need).
+
+On the other hand for interface-file instance declarations, the decl
+specifies the name of the dictionary function, and it has a binding elsewhere
+in the interface file:
+ instance {Eq Int} = dEqInt
+ dEqInt :: {Eq Int} <pragma info>
+
+So again we treat source code and interface file code slightly differently.
+
+Source code:
+ - Source code instance decls have a Nothing in the (Maybe name) field
+ (see data InstDecl below)
+
+ - The typechecker makes up a Local name for the dict fun for any source-code
+ instance decl, whether it comes from a source-code instance decl, or whether
+ the instance decl is derived from some other construct (e.g. 'deriving').
+
+ - The occurrence name it chooses is derived from the instance decl (just for
+ documentation really) --- e.g. dNumInt. Two dict funs may share a common
+ occurrence name, but will have different uniques. E.g.
+ instance Foo [Int] where ...
+ instance Foo [Bool] where ...
+ These might both be dFooList
+
+ - The CoreTidy phase globalises the name, and ensures the occurrence name is
+ unique (this isn't special to dict funs). So we'd get dFooList and dFooList1.
+
+ - We can take this relaxed approach (changing the occurrence name later)
+ because dict fun Ids are not captured in a TyCon or Class (unlike default
+ methods, say). Instead, they are kept separately in the InstEnv. This
+ makes it easy to adjust them after compiling a module. (Once we've finished
+ compiling that module, they don't change any more.)
+
+
+Interface file code:
+ - The instance decl gives the dict fun name, so the InstDecl has a (Just name)
+ in the (Maybe name) field.
+
+ - RnHsSyn.instDeclFVs treats the dict fun name as free in the decl, so that we
+ suck in the dfun binding
-Plan of attack:
- - Do *not* make them point to the parent class decl
- - Interface-file decls: treat just like Type A
- - Source-file decls: the names aren't in the decl at all;
- instead the typechecker makes them up
\begin{code}
data TyClDecl name pat
- = IfaceSig name -- It may seem odd to classify an interface-file signature
- (HsType name) -- as a 'TyClDecl', but it's very convenient. These three
- [HsIdInfo name] -- are the kind that appear in interface files.
- SrcLoc
-
- | TyData NewOrData
- (HsContext name) -- context
- name -- type constructor
- [HsTyVarBndr name] -- type variables
- [ConDecl name] -- data constructors (empty if abstract)
- Int -- Number of data constructors (valid even if type is abstract)
- (Maybe [name]) -- derivings; Nothing => not specified
+ = IfaceSig { tcdName :: name, -- It may seem odd to classify an interface-file signature
+ tcdType :: HsType name, -- as a 'TyClDecl', but it's very convenient. These three
+ tcdIdInfo :: [HsIdInfo name], -- are the kind that appear in interface files.
+ tcdLoc :: SrcLoc
+ }
+
+ | TyData { tcdND :: NewOrData,
+ tcdCtxt :: HsContext name, -- context
+ tcdName :: name, -- type constructor
+ tcdTyVars :: [HsTyVarBndr name], -- type variables
+ tcdCons :: [ConDecl name], -- data constructors (empty if abstract)
+ tcdNCons :: Int, -- Number of data constructors (valid even if type is abstract)
+ tcdDerivs :: Maybe [name], -- derivings; Nothing => not specified
-- (i.e., derive default); Just [] => derive
-- *nothing*; Just <list> => as you would
-- expect...
- SrcLoc
- name -- generic converter functions
- name -- generic converter functions
-
- | TySynonym name -- type constructor
- [HsTyVarBndr name] -- type variables
- (HsType name) -- synonym expansion
- SrcLoc
-
- | ClassDecl (HsContext name) -- context...
- name -- name of the class
- [HsTyVarBndr name] -- the class type variables
- [FunDep name] -- functional dependencies
- [Sig name] -- methods' signatures
- (MonoBinds name pat) -- default methods
- (ClassDeclSysNames name)
- SrcLoc
+ tcdSysNames :: DataSysNames name, -- Generic converter functions
+ tcdLoc :: SrcLoc
+ }
+
+ | TySynonym { tcdName :: name, -- type constructor
+ tcdTyVars :: [HsTyVarBndr name], -- type variables
+ tcdSynRhs :: HsType name, -- synonym expansion
+ tcdLoc :: SrcLoc
+ }
+
+ | ClassDecl { tcdCtxt :: HsContext name, -- Context...
+ tcdName :: name, -- Name of the class
+ tcdTyVars :: [HsTyVarBndr name], -- The class type variables
+ tcdFDs :: [FunDep name], -- Functional dependencies
+ tcdSigs :: [Sig name], -- Methods' signatures
+ tcdMeths :: Maybe (MonoBinds name pat), -- Default methods
+ -- Nothing for imported class decls
+ -- Just bs for source class decls
+ tcdSysNames :: ClassSysNames name,
+ tcdLoc :: SrcLoc
+ }
\end{code}
Simple classifiers
\begin{code}
isIfaceSigDecl, isDataDecl, isSynDecl, isClassDecl :: TyClDecl name pat -> Bool
-isIfaceSigDecl (IfaceSig _ _ _ _) = True
-isIfaceSigDecl other = False
+isIfaceSigDecl (IfaceSig {}) = True
+isIfaceSigDecl other = False
-isSynDecl (TySynonym _ _ _ _) = True
-isSynDecl other = False
+isSynDecl (TySynonym {}) = True
+isSynDecl other = False
-isDataDecl (TyData _ _ _ _ _ _ _ _ _ _) = True
-isDataDecl other = False
+isDataDecl (TyData {}) = True
+isDataDecl other = False
-isClassDecl (ClassDecl _ _ _ _ _ _ _ _ ) = True
-isClassDecl other = False
+isClassDecl (ClassDecl {}) = True
+isClassDecl other = False
\end{code}
Dealing with names
\begin{code}
+--------------------------------
tyClDeclName :: TyClDecl name pat -> name
-tyClDeclName (IfaceSig name _ _ _) = name
-tyClDeclName (TyData _ _ name _ _ _ _ _ _ _) = name
-tyClDeclName (TySynonym name _ _ _) = name
-tyClDeclName (ClassDecl _ name _ _ _ _ _ _) = name
-
+tyClDeclName tycl_decl = tcdName tycl_decl
+--------------------------------
tyClDeclNames :: Eq name => TyClDecl name pat -> [(name, SrcLoc)]
--- Returns all the binding names of the decl, along with their SrcLocs
+-- Returns all the *binding* names of the decl, along with their SrcLocs
-- The first one is guaranteed to be the name of the decl
-- For record fields, the first one counts as the SrcLoc
-- We use the equality to filter out duplicate field names
-tyClDeclNames (TySynonym name _ _ loc)
- = [(name,loc)]
+tyClDeclNames (TySynonym {tcdName = name, tcdLoc = loc}) = [(name,loc)]
+tyClDeclNames (IfaceSig {tcdName = name, tcdLoc = loc}) = [(name,loc)]
-tyClDeclNames (ClassDecl _ cls_name _ _ sigs _ _ loc)
+tyClDeclNames (ClassDecl {tcdName = cls_name, tcdSigs = sigs, tcdLoc = loc})
= (cls_name,loc) : [(n,loc) | ClassOpSig n _ _ loc <- sigs]
-tyClDeclNames (TyData _ _ tc_name _ cons _ _ loc _ _)
+tyClDeclNames (TyData {tcdName = tc_name, tcdCons = cons, tcdLoc = loc})
= (tc_name,loc) : conDeclsNames cons
-tyClDeclNames (IfaceSig name _ _ loc) = [(name,loc)]
-type ClassDeclSysNames name = [name]
- -- [tycon, datacon wrapper, datacon worker,
- -- superclass selector 1, ..., superclass selector n]
- -- They are kept in a list rather than a tuple to make the
- -- renamer easier.
+--------------------------------
+-- The "system names" are extra implicit names *bound* by the decl.
+-- They are kept in a list rather than a tuple
+-- to make the renamer easier.
+
+type ClassSysNames name = [name]
+-- For class decls they are:
+-- [tycon, datacon wrapper, datacon worker,
+-- superclass selector 1, ..., superclass selector n]
+
+type DataSysNames name = [name]
+-- For data decls they are
+-- [from, to]
+-- where from :: T -> Tring
+-- to :: Tring -> T
+
+tyClDeclSysNames :: TyClDecl name pat -> [(name, SrcLoc)]
+-- Similar to tyClDeclNames, but returns the "implicit"
+-- or "system" names of the declaration
+
+tyClDeclSysNames (ClassDecl {tcdSysNames = names, tcdLoc = loc})
+ = [(n,loc) | n <- names]
+tyClDeclSysNames (TyData {tcdCons = cons, tcdSysNames = names, tcdLoc = loc})
+ = [(n,loc) | n <- names] ++
+ [(wkr_name,loc) | ConDecl _ wkr_name _ _ _ loc <- cons]
+tyClDeclSysNames decl = []
+
mkClassDeclSysNames :: (name, name, name, [name]) -> [name]
getClassDeclSysNames :: [name] -> (name, name, name, [name])
\end{code}
\begin{code}
-instance Ord name => Eq (TyClDecl name pat) where
+instance (NamedThing name, Ord name) => Eq (TyClDecl name pat) where
-- Used only when building interface files
- (==) (IfaceSig n1 t1 i1 _)
- (IfaceSig n2 t2 i2 _) = n1==n2 && t1==t2 && i1==i2
-
- (==) (TyData nd1 cxt1 n1 tvs1 cons1 _ _ _ _ _)
- (TyData nd2 cxt2 n2 tvs2 cons2 _ _ _ _ _)
- = n1 == n2 &&
- nd1 == nd2 &&
- eqWithHsTyVars tvs1 tvs2 (\ env ->
- eq_hsContext env cxt1 cxt2 &&
- eqListBy (eq_ConDecl env) cons1 cons2
- )
-
- (==) (TySynonym n1 tvs1 ty1 _)
- (TySynonym n2 tvs2 ty2 _)
- = n1 == n2 &&
- eqWithHsTyVars tvs1 tvs2 (\ env -> eq_hsType env ty1 ty2)
-
- (==) (ClassDecl cxt1 n1 tvs1 fds1 sigs1 _ _ _ )
- (ClassDecl cxt2 n2 tvs2 fds2 sigs2 _ _ _ )
- = n1 == n2 &&
- eqWithHsTyVars tvs1 tvs2 (\ env ->
- eq_hsContext env cxt1 cxt2 &&
- eqListBy (eq_hsFD env) fds1 fds2 &&
- eqListBy (eq_cls_sig env) sigs1 sigs2
+ (==) d1@(IfaceSig {}) d2@(IfaceSig {})
+ = tcdName d1 == tcdName d2 &&
+ tcdType d1 == tcdType d2 &&
+ tcdIdInfo d1 == tcdIdInfo d2
+
+ (==) d1@(TyData {}) d2@(TyData {})
+ = tcdName d1 == tcdName d2 &&
+ tcdND d1 == tcdND d2 &&
+ eqWithHsTyVars (tcdTyVars d1) (tcdTyVars d2) (\ env ->
+ eq_hsContext env (tcdCtxt d1) (tcdCtxt d2) &&
+ eqListBy (eq_ConDecl env) (tcdCons d1) (tcdCons d2)
+ )
+
+ (==) d1@(TySynonym {}) d2@(TySynonym {})
+ = tcdName d1 == tcdName d2 &&
+ eqWithHsTyVars (tcdTyVars d1) (tcdTyVars d2) (\ env ->
+ eq_hsType env (tcdSynRhs d1) (tcdSynRhs d2)
+ )
+
+ (==) d1@(ClassDecl {}) d2@(ClassDecl {})
+ = tcdName d1 == tcdName d2 &&
+ eqWithHsTyVars (tcdTyVars d1) (tcdTyVars d2) (\ env ->
+ eq_hsContext env (tcdCtxt d1) (tcdCtxt d2) &&
+ eqListBy (eq_hsFD env) (tcdFDs d1) (tcdFDs d2) &&
+ eqListBy (eq_cls_sig env) (tcdSigs d1) (tcdSigs d2)
)
(==) _ _ = False -- default case
-
eq_hsFD env (ns1,ms1) (ns2,ms2)
= eqListBy (eq_hsVar env) ns1 ns2 && eqListBy (eq_hsVar env) ms1 ms2
-- This is used for comparing declarations before putting
-- them into interface files, and the name of the default
-- method isn't relevant
- Nothing `eq_dm` Nothing = True
- (Just NoDefMeth) `eq_dm` (Just NoDefMeth) = True
- (Just GenDefMeth) `eq_dm` (Just GenDefMeth) = True
- (Just (DefMeth _)) `eq_dm` (Just (DefMeth _)) = True
- dm1 `eq_dm` dm2 = False
+ NoDefMeth `eq_dm` NoDefMeth = True
+ GenDefMeth `eq_dm` GenDefMeth = True
+ DefMeth _ `eq_dm` DefMeth _ = True
+ dm1 `eq_dm` dm2 = False
\end{code}
countTyClDecls :: [TyClDecl name pat] -> (Int, Int, Int, Int, Int)
-- class, data, newtype, synonym decls
countTyClDecls decls
- = (length [() | ClassDecl _ _ _ _ _ _ _ _ <- decls],
- length [() | TyData DataType _ _ _ _ _ _ _ _ _ <- decls],
- length [() | TyData NewType _ _ _ _ _ _ _ _ _ <- decls],
- length [() | TySynonym _ _ _ _ <- decls],
- length [() | IfaceSig _ _ _ _ <- decls])
+ = (length [() | ClassDecl {} <- decls],
+ length [() | TySynonym {} <- decls],
+ length [() | IfaceSig {} <- decls],
+ length [() | TyData {tcdND = DataType} <- decls],
+ length [() | TyData {tcdND = NewType} <- decls])
\end{code}
\begin{code}
-instance (Outputable name, Outputable pat)
+instance (NamedThing name, Outputable name, Outputable pat)
=> Outputable (TyClDecl name pat) where
- ppr (IfaceSig var ty info _) = hsep [ppr var, dcolon, ppr ty, pprHsIdInfo info]
+ ppr (IfaceSig {tcdName = var, tcdType = ty, tcdIdInfo = info})
+ = hsep [ppr var, dcolon, ppr ty, pprHsIdInfo info]
- ppr (TySynonym tycon tyvars mono_ty src_loc)
+ ppr (TySynonym {tcdName = tycon, tcdTyVars = tyvars, tcdSynRhs = mono_ty})
= hang (ptext SLIT("type") <+> pp_decl_head [] tycon tyvars <+> equals)
4 (ppr mono_ty)
- ppr (TyData new_or_data context tycon tyvars condecls ncons
- derivings src_loc gen_conv1 gen_conv2) -- The generic names are not printed out ATM
- = pp_tydecl
- (ptext keyword <+> pp_decl_head context tycon tyvars <+> equals)
+ ppr (TyData {tcdND = new_or_data, tcdCtxt = context, tcdName = tycon,
+ tcdTyVars = tyvars, tcdCons = condecls, tcdNCons = ncons,
+ tcdDerivs = derivings})
+ = pp_tydecl (ptext keyword <+> pp_decl_head context tycon tyvars <+> equals)
(pp_condecls condecls ncons)
derivings
where
NewType -> SLIT("newtype")
DataType -> SLIT("data")
- ppr (ClassDecl context clas tyvars fds sigs methods _ src_loc)
+ ppr (ClassDecl {tcdCtxt = context, tcdName = clas, tcdTyVars = tyvars, tcdFDs = fds,
+ tcdSigs = sigs, tcdMeths = methods})
| null sigs -- No "where" part
= top_matter
\end{code}
\begin{code}
+conDetailsTys :: ConDetails name -> [HsType name]
+conDetailsTys (VanillaCon btys) = map getBangType btys
+conDetailsTys (InfixCon bty1 bty2) = [getBangType bty1, getBangType bty2]
+conDetailsTys (RecCon fields) = [getBangType bty | (_, bty) <- fields]
+
+
eq_ConDecl env (ConDecl n1 _ tvs1 cxt1 cds1 _)
(ConDecl n2 _ tvs2 cxt2 cds2 _)
= n1 == n2 &&
= RuleBndr name
| RuleBndrSig name (HsType name)
-instance Ord name => Eq (RuleDecl name pat) where
+instance (NamedThing name, Ord name) => Eq (RuleDecl name pat) where
-- Works for IfaceRules only; used when comparing interface file versions
(IfaceRule n1 bs1 f1 es1 rhs1 _) == (IfaceRule n2 bs2 f2 es2 rhs2 _)
= n1==n2 && f1 == f2 &&
eq_ufBinders emptyEqHsEnv bs1 bs2 (\env ->
eqListBy (eq_ufExpr env) (rhs1:es1) (rhs2:es2))
-instance (Outputable name, Outputable pat)
+instance (NamedThing name, Outputable name, Outputable pat)
=> Outputable (RuleDecl name pat) where
ppr (HsRule name tvs ns lhs rhs loc)
= sep [text "{-# RULES" <+> doubleQuotes (ptext name),
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