%
\section[HsDecls]{Abstract syntax: global declarations}
-Definitions for: @TyDecl@ and @ConDecl@, @ClassDecl@,
+Definitions for: @TyDecl@ and @oCnDecl@, @ClassDecl@,
@InstDecl@, @DefaultDecl@ and @ForeignDecl@.
\begin{code}
module HsDecls (
HsDecl(..), TyClDecl(..), InstDecl(..), RuleDecl(..), RuleBndr(..),
- DefaultDecl(..), ForeignDecl(..), ForKind(..),
- ExtName(..), isDynamicExtName, extNameStatic,
+ DefaultDecl(..),
+ ForeignDecl(..), FoImport(..), FoExport(..), FoType(..),
ConDecl(..), ConDetails(..),
- BangType(..), getBangType,
+ BangType(..), getBangType, getBangStrictness, unbangedType,
DeprecDecl(..), DeprecTxt,
- hsDeclName, instDeclName, tyClDeclName, tyClDeclNames, tyClDeclSysNames,
+ hsDeclName, instDeclName,
+ tyClDeclName, tyClDeclNames, tyClDeclSysNames, tyClDeclTyVars,
isClassDecl, isSynDecl, isDataDecl, isIfaceSigDecl, countTyClDecls,
mkClassDeclSysNames, isIfaceRuleDecl, ifaceRuleDeclName,
getClassDeclSysNames, conDetailsTys
-- friends:
import HsBinds ( HsBinds, MonoBinds, Sig(..), FixitySig(..) )
import HsExpr ( HsExpr )
+import HsImpExp ( ppr_var )
import HsTypes
import PprCore ( pprCoreRule )
import HsCore ( UfExpr, UfBinder, HsIdInfo, pprHsIdInfo,
eq_ufBinders, eq_ufExpr, pprUfExpr
)
-import CoreSyn ( CoreRule(..) )
-import BasicTypes ( NewOrData(..) )
-import CallConv ( CallConv, pprCallConv )
+import CoreSyn ( CoreRule(..), RuleName )
+import BasicTypes ( NewOrData(..), StrictnessMark(..), Activation(..) )
+import ForeignCall ( CExportSpec, CCallSpec, DNCallSpec, CCallConv )
-- others:
import Name ( NamedThing )
import FunDeps ( pprFundeps )
import Class ( FunDep, DefMeth(..) )
-import CStrings ( CLabelString, pprCLabelString )
+import CStrings ( CLabelString )
import Outputable
+import Util ( eqListBy )
import SrcLoc ( SrcLoc )
+import FastString
+
+import Maybe ( isNothing, fromJust )
\end{code}
hsDeclName :: (NamedThing name, Outputable name, Outputable pat)
=> HsDecl name pat -> name
#endif
-hsDeclName (TyClD decl) = tyClDeclName decl
-hsDeclName (InstD decl) = instDeclName decl
-hsDeclName (ForD (ForeignDecl name _ _ _ _ _)) = name
-hsDeclName (FixD (FixitySig name _ _)) = name
+hsDeclName (TyClD decl) = tyClDeclName decl
+hsDeclName (InstD decl) = instDeclName decl
+hsDeclName (ForD decl) = forDeclName decl
+hsDeclName (FixD (FixitySig name _ _)) = name
-- Others don't make sense
#ifdef DEBUG
hsDeclName x = pprPanic "HsDecls.hsDeclName" (ppr x)
%* *
%************************************************************************
-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}
+-- TyClDecls are precisely the kind of declarations that can
+-- appear in interface files; or (internally) in GHC's interface
+-- for a module. That's why (despite the misnomer) IfaceSig and ForeignType
+-- are both in TyClDecl
+
data TyClDecl name pat
= 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.
+ tcdType :: HsType name, -- as a 'TyClDecl', but it's very convenient.
+ tcdIdInfo :: [HsIdInfo name],
tcdLoc :: SrcLoc
}
+ | ForeignType { tcdName :: name, -- See remarks about IfaceSig above
+ tcdExtName :: Maybe FastString,
+ tcdFoType :: FoType,
+ tcdLoc :: SrcLoc }
+
| TyData { tcdND :: NewOrData,
tcdCtxt :: HsContext name, -- context
tcdName :: name, -- type constructor
-- For record fields, the first one counts as the SrcLoc
-- We use the equality to filter out duplicate field names
-tyClDeclNames (TySynonym {tcdName = name, tcdLoc = loc}) = [(name,loc)]
-tyClDeclNames (IfaceSig {tcdName = name, tcdLoc = loc}) = [(name,loc)]
+tyClDeclNames (TySynonym {tcdName = name, tcdLoc = loc}) = [(name,loc)]
+tyClDeclNames (IfaceSig {tcdName = name, tcdLoc = loc}) = [(name,loc)]
+tyClDeclNames (ForeignType {tcdName = name, tcdLoc = loc}) = [(name,loc)]
tyClDeclNames (ClassDecl {tcdName = cls_name, tcdSigs = sigs, tcdLoc = loc})
= (cls_name,loc) : [(n,loc) | ClassOpSig n _ _ loc <- sigs]
= (tc_name,loc) : conDeclsNames cons
+tyClDeclTyVars (TySynonym {tcdTyVars = tvs}) = tvs
+tyClDeclTyVars (TyData {tcdTyVars = tvs}) = tvs
+tyClDeclTyVars (ClassDecl {tcdTyVars = tvs}) = tvs
+tyClDeclTyVars (ForeignType {}) = []
+tyClDeclTyVars (IfaceSig {}) = []
+
+
--------------------------------
-- The "system names" are extra implicit names *bound* by the decl.
-- They are kept in a list rather than a tuple
-- Similar to tyClDeclNames, but returns the "implicit"
-- or "system" names of the declaration
-tyClDeclSysNames (ClassDecl {tcdSysNames = names, tcdLoc = loc, tcdSigs = sigs})
+tyClDeclSysNames (ClassDecl {tcdSysNames = names, tcdLoc = loc})
= [(n,loc) | n <- names]
tyClDeclSysNames (TyData {tcdCons = cons, tcdSysNames = names, tcdLoc = loc})
= [(n,loc) | n <- names] ++
tcdType d1 == tcdType d2 &&
tcdIdInfo d1 == tcdIdInfo d2
+ (==) d1@(ForeignType {}) d2@(ForeignType {})
+ = tcdName d1 == tcdName d2 &&
+ tcdFoType d1 == tcdFoType d2
+
(==) d1@(TyData {}) d2@(TyData {})
= tcdName d1 == tcdName d2 &&
tcdND d1 == tcdND d2 &&
=> Outputable (TyClDecl name pat) where
ppr (IfaceSig {tcdName = var, tcdType = ty, tcdIdInfo = info})
- = hsep [ppr var, dcolon, ppr ty, pprHsIdInfo info]
+ = getPprStyle $ \ sty ->
+ hsep [ if ifaceStyle sty then ppr var else ppr_var var,
+ dcolon, ppr ty, pprHsIdInfo info
+ ]
+
+ ppr (ForeignType {tcdName = tycon})
+ = hsep [ptext SLIT("foreign import type dotnet"), ppr tycon]
ppr (TySynonym {tcdName = tycon, tcdTyVars = tyvars, tcdSynRhs = mono_ty})
= hang (ptext SLIT("type") <+> pp_decl_head [] 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_tydecl (ptext keyword <+> pp_decl_head context tycon tyvars)
(pp_condecls condecls ncons)
derivings
where
where
top_matter = ptext SLIT("class") <+> pp_decl_head context clas tyvars <+> pprFundeps fds
ppr_sig sig = ppr sig <> semi
+
pp_methods = getPprStyle $ \ sty ->
- if ifaceStyle sty then empty else ppr methods
+ if ifaceStyle sty || isNothing methods
+ then empty
+ else ppr (fromJust methods)
pp_decl_head :: Outputable name => HsContext name -> name -> [HsTyVarBndr name] -> SDoc
pp_decl_head context thing tyvars = hsep [pprHsContext context, ppr thing, interppSP tyvars]
pp_condecls [] ncons = ptext SLIT("{- abstract with") <+> int ncons <+> ptext SLIT("constructors -}")
-pp_condecls (c:cs) ncons = sep (ppr c : map (\ c -> ptext SLIT("|") <+> ppr c) cs)
+pp_condecls (c:cs) ncons = equals <+> sep (ppr c : map (\ c -> ptext SLIT("|") <+> ppr c) cs)
pp_tydecl pp_head pp_decl_rhs derivings
= hang pp_head 4 (sep [
\end{code}
\begin{code}
-data BangType name
- = Banged (HsType name) -- HsType: to allow Haskell extensions
- | Unbanged (HsType name) -- (MonoType only needed for straight Haskell)
- | Unpacked (HsType name) -- Field is strict and to be unpacked if poss.
-
-getBangType (Banged ty) = ty
-getBangType (Unbanged ty) = ty
-getBangType (Unpacked ty) = ty
-
-eq_btype env (Banged t1) (Banged t2) = eq_hsType env t1 t2
-eq_btype env (Unbanged t1) (Unbanged t2) = eq_hsType env t1 t2
-eq_btype env (Unpacked t1) (Unpacked t2) = eq_hsType env t1 t2
-eq_btype env _ _ = False
+data BangType name = BangType StrictnessMark (HsType name)
+
+getBangType (BangType _ ty) = ty
+getBangStrictness (BangType s _) = s
+
+unbangedType ty = BangType NotMarkedStrict ty
+
+eq_btype env (BangType s1 t1) (BangType s2 t2) = s1==s2 && eq_hsType env t1 t2
\end{code}
\begin{code}
ppr_con_details con (InfixCon ty1 ty2)
= hsep [ppr_bang ty1, ppr con, ppr_bang ty2]
+-- ConDecls generated by MkIface.ifaceTyCls always have a VanillaCon, even
+-- if the constructor is an infix one. This is because in an interface file
+-- we don't distinguish between the two. Hence when printing these for the
+-- user, we need to parenthesise infix constructor names.
ppr_con_details con (VanillaCon tys)
- = ppr con <+> hsep (map (ppr_bang) tys)
+ = getPprStyle $ \ sty ->
+ hsep ((if ifaceStyle sty then ppr con else ppr_var con)
+ : map (ppr_bang) tys)
ppr_con_details con (RecCon fields)
- = ppr con <+> braces (hsep (punctuate comma (map ppr_field fields)))
+ = ppr con <+> braces (sep (punctuate comma (map ppr_field fields)))
where
ppr_field (ns, ty) = hsep (map (ppr) ns) <+>
dcolon <+>
instance Outputable name => Outputable (BangType name) where
ppr = ppr_bang
-ppr_bang (Banged ty) = ptext SLIT("!") <> pprParendHsType ty
-ppr_bang (Unbanged ty) = pprParendHsType ty
-ppr_bang (Unpacked ty) = ptext SLIT("! !") <> pprParendHsType ty
+ppr_bang (BangType s ty) = ppr s <> pprParendHsType ty
\end{code}
%************************************************************************
\begin{code}
-data ForeignDecl name =
- ForeignDecl
- name
- ForKind
- (HsType name)
- ExtName
- CallConv
- SrcLoc
-
-instance (Outputable name)
- => Outputable (ForeignDecl name) where
-
- ppr (ForeignDecl nm imp_exp ty ext_name cconv src_loc)
- = ptext SLIT("foreign") <+> ppr_imp_exp <+> pprCallConv cconv <+>
- ppr ext_name <+> ppr_unsafe <+> ppr nm <+> dcolon <+> ppr ty
- where
- (ppr_imp_exp, ppr_unsafe) =
- case imp_exp of
- FoLabel -> (ptext SLIT("label"), empty)
- FoExport -> (ptext SLIT("export"), empty)
- FoImport us
- | us -> (ptext SLIT("import"), ptext SLIT("unsafe"))
- | otherwise -> (ptext SLIT("import"), empty)
-
-data ForKind
- = FoLabel
- | FoExport
- | FoImport Bool -- True => unsafe call.
-
-data ExtName
- = Dynamic
- | ExtName CLabelString -- The external name of the foreign thing,
- (Maybe CLabelString) -- and optionally its DLL or module name
- -- Both of these are completely unencoded;
- -- we just print them as they are
-
-isDynamicExtName :: ExtName -> Bool
-isDynamicExtName Dynamic = True
-isDynamicExtName _ = False
-
-extNameStatic :: ExtName -> CLabelString
-extNameStatic (ExtName f _) = f
-extNameStatic Dynamic = panic "staticExtName: Dynamic - shouldn't ever happen."
-
-instance Outputable ExtName where
- ppr Dynamic = ptext SLIT("dynamic")
- ppr (ExtName nm mb_mod) =
- case mb_mod of { Nothing -> empty; Just m -> doubleQuotes (ptext m) } <+>
- doubleQuotes (pprCLabelString nm)
+data ForeignDecl name
+ = ForeignImport name (HsType name) FoImport SrcLoc
+ | ForeignExport name (HsType name) FoExport SrcLoc
+
+forDeclName (ForeignImport n _ _ _) = n
+forDeclName (ForeignExport n _ _ _) = n
+
+data FoImport
+ = LblImport CLabelString -- foreign label
+ | CImport CCallSpec -- foreign import
+ | CDynImport CCallConv -- foreign export dynamic
+ | DNImport DNCallSpec -- foreign import dotnet
+
+data FoExport = CExport CExportSpec
+
+data FoType = DNType -- In due course we'll add subtype stuff
+ deriving( Eq ) -- Used for equality instance for TyClDecl
+
+instance Outputable name => Outputable (ForeignDecl name) where
+ ppr (ForeignImport nm ty (LblImport lbl) src_loc)
+ = ptext SLIT("foreign label") <+> ppr lbl <+> ppr nm <+> dcolon <+> ppr ty
+ ppr (ForeignImport nm ty decl src_loc)
+ = ptext SLIT("foreign import") <+> ppr decl <+> ppr nm <+> dcolon <+> ppr ty
+ ppr (ForeignExport nm ty decl src_loc)
+ = ptext SLIT("foreign export") <+> ppr decl <+> ppr nm <+> dcolon <+> ppr ty
+
+instance Outputable FoImport where
+ ppr (CImport d) = ppr d
+ ppr (CDynImport conv) = text "dynamic" <+> ppr conv
+ ppr (DNImport d) = ptext SLIT("dotnet") <+> ppr d
+ ppr (LblImport l) = ptext SLIT("label") <+> ppr l
+
+instance Outputable FoExport where
+ ppr (CExport d) = ppr d
+
+instance Outputable FoType where
+ ppr DNType = ptext SLIT("type dotnet")
\end{code}
+
%************************************************************************
%* *
\subsection{Transformation rules}
\begin{code}
data RuleDecl name pat
= HsRule -- Source rule
- FAST_STRING -- Rule name
+ RuleName -- Rule name
+ Activation
[name] -- Forall'd tyvars, filled in by the renamer with
-- tyvars mentioned in sigs; then filled out by typechecker
[RuleBndr name] -- Forall'd term vars
SrcLoc
| IfaceRule -- One that's come in from an interface file; pre-typecheck
- FAST_STRING
+ RuleName
+ Activation
[UfBinder name] -- Tyvars and term vars
name -- Head of lhs
[UfExpr name] -- Args of LHS
name -- Head of LHS
CoreRule
-isIfaceRuleDecl (HsRule _ _ _ _ _ _) = False
-isIfaceRuleDecl other = True
+isIfaceRuleDecl :: RuleDecl name pat -> Bool
+isIfaceRuleDecl (HsRule _ _ _ _ _ _ _) = False
+isIfaceRuleDecl other = True
ifaceRuleDeclName :: RuleDecl name pat -> name
-ifaceRuleDeclName (IfaceRule _ _ n _ _ _) = n
-ifaceRuleDeclName (IfaceRuleOut n r) = n
-ifaceRuleDeclName (HsRule fs _ _ _ _ _) = pprPanic "ifaceRuleDeclName" (ppr fs)
+ifaceRuleDeclName (IfaceRule _ _ _ n _ _ _) = n
+ifaceRuleDeclName (IfaceRuleOut n r) = n
+ifaceRuleDeclName (HsRule fs _ _ _ _ _ _) = pprPanic "ifaceRuleDeclName" (ppr fs)
data RuleBndr name
= RuleBndr name
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 &&
+ (IfaceRule n1 a1 bs1 f1 es1 rhs1 _) == (IfaceRule n2 a2 bs2 f2 es2 rhs2 _)
+ = n1==n2 && f1 == f2 && a1==a2 &&
eq_ufBinders emptyEqHsEnv bs1 bs2 (\env ->
eqListBy (eq_ufExpr env) (rhs1:es1) (rhs2:es2))
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),
+ ppr (HsRule name act tvs ns lhs rhs loc)
+ = sep [text "{-# RULES" <+> doubleQuotes (ptext name) <+> ppr act,
pp_forall, ppr lhs, equals <+> ppr rhs,
text "#-}" ]
where
fsep (map ppr tvs ++ map ppr ns)
<> dot
- ppr (IfaceRule name tpl_vars fn tpl_args rhs loc)
- = hsep [ doubleQuotes (ptext name),
+ ppr (IfaceRule name act tpl_vars fn tpl_args rhs loc)
+ = hsep [ doubleQuotes (ptext name), ppr act,
ptext SLIT("__forall") <+> braces (interppSP tpl_vars),
ppr fn <+> sep (map (pprUfExpr parens) tpl_args),
ptext SLIT("=") <+> ppr rhs
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