%
+% (c) The University of Glasgow 2006
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[HsBinds]{Abstract syntax: top-level bindings and signatures}
Datatype for: @BindGroup@, @Bind@, @Sig@, @Bind@.
\begin{code}
+{-# OPTIONS -w #-}
+-- The above warning supression flag is a temporary kludge.
+-- While working on this module you are encouraged to remove it and fix
+-- any warnings in the module. See
+-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
+-- for details
+
module HsBinds where
#include "HsVersions.h"
GRHSs, pprPatBind )
import {-# SOURCE #-} HsPat ( LPat )
-import HsTypes ( LHsType, PostTcType )
-import PprCore ( {- instances -} )
-import Coercion ( Coercion )
-import Type ( Type, pprParendType )
-import Name ( Name )
-import NameSet ( NameSet, elemNameSet )
-import BasicTypes ( IPName, RecFlag(..), InlineSpec(..), Fixity )
+import HsTypes
+import PprCore ()
+import Coercion
+import Type
+import Name
+import NameSet
+import BasicTypes
import Outputable
-import SrcLoc ( Located(..), SrcSpan, unLoc )
-import Util ( sortLe )
-import Var ( TyVar, DictId, Id, Var )
-import Bag ( Bag, emptyBag, isEmptyBag, bagToList, unionBags, unionManyBags )
+import SrcLoc
+import Util
+import Var
+import Bag
\end{code}
%************************************************************************
Global bindings (where clauses)
\begin{code}
-data HsLocalBinds id -- Bindings in a 'let' expression
- -- or a 'where' clause
- = HsValBinds (HsValBinds id)
- | HsIPBinds (HsIPBinds id)
-
+-- During renaming, we need bindings where the left-hand sides
+-- have been renamed but the the right-hand sides have not.
+-- the ...LR datatypes are parametrized by two id types,
+-- one for the left and one for the right.
+-- Other than during renaming, these will be the same.
+
+type HsLocalBinds id = HsLocalBindsLR id id
+
+data HsLocalBindsLR idL idR -- Bindings in a 'let' expression
+ -- or a 'where' clause
+ = HsValBinds (HsValBindsLR idL idR)
+ | HsIPBinds (HsIPBinds idR)
| EmptyLocalBinds
-data HsValBinds id -- Value bindings (not implicit parameters)
- = ValBindsIn -- Before typechecking
- (LHsBinds id) [LSig id] -- Not dependency analysed
+type HsValBinds id = HsValBindsLR id id
+
+data HsValBindsLR idL idR -- Value bindings (not implicit parameters)
+ = ValBindsIn -- Before typechecking
+ (LHsBindsLR idL idR) [LSig idR] -- Not dependency analysed
-- Recursive by default
- | ValBindsOut -- After renaming
- [(RecFlag, LHsBinds id)] -- Dependency analysed
+ | ValBindsOut -- After renaming
+ [(RecFlag, LHsBinds idL)] -- Dependency analysed, later bindings
+ -- in the list may depend on earlier
+ -- ones.
[LSig Name]
type LHsBinds id = Bag (LHsBind id)
type DictBinds id = LHsBinds id -- Used for dictionary or method bindings
type LHsBind id = Located (HsBind id)
+type HsBind id = HsBindLR id id
+
+type LHsBindLR idL idR = Located (HsBindLR idL idR)
+type LHsBindsLR idL idR = Bag (LHsBindLR idL idR)
-data HsBind id
+data HsBindLR idL idR
= FunBind { -- FunBind is used for both functions f x = e
-- and variables f = \x -> e
-- Reason 1: Special case for type inference: see TcBinds.tcMonoBinds
-- parses as a pattern binding, just like
-- (f :: a -> a) = ...
- fun_id :: Located id,
+ fun_id :: Located idL,
fun_infix :: Bool, -- True => infix declaration
- fun_matches :: MatchGroup id, -- The payload
+ fun_matches :: MatchGroup idR, -- The payload
fun_co_fn :: HsWrapper, -- Coercion from the type of the MatchGroup to the type of
-- the Id. Example:
-- type Int -> forall a'. a' -> a'
-- Notice that the coercion captures the free a'.
- bind_fvs :: NameSet -- After the renamer, this contains a superset of the
+ bind_fvs :: NameSet, -- After the renamer, this contains a superset of the
-- Names of the other binders in this binding group that
-- are free in the RHS of the defn
-- Before renaming, and after typechecking,
-- the field is unused; it's just an error thunk
+
+ fun_tick :: Maybe (Int,[idR]) -- This is the (optional) module-local tick number.
}
| PatBind { -- The pattern is never a simple variable;
-- That case is done by FunBind
- pat_lhs :: LPat id,
- pat_rhs :: GRHSs id,
+ pat_lhs :: LPat idL,
+ pat_rhs :: GRHSs idR,
pat_rhs_ty :: PostTcType, -- Type of the GRHSs
bind_fvs :: NameSet -- Same as for FunBind
}
| VarBind { -- Dictionary binding and suchlike
- var_id :: id, -- All VarBinds are introduced by the type checker
- var_rhs :: LHsExpr id -- Located only for consistency
+ var_id :: idL, -- All VarBinds are introduced by the type checker
+ var_rhs :: LHsExpr idR -- Located only for consistency
}
| AbsBinds { -- Binds abstraction; TRANSLATION
- abs_tvs :: [TyVar],
+ abs_tvs :: [TyVar],
abs_dicts :: [DictId],
- abs_exports :: [([TyVar], id, id, [Prag])], -- (tvs, poly_id, mono_id, prags)
- abs_binds :: LHsBinds id -- The dictionary bindings and typechecked user bindings
+ -- AbsBinds only gets used when idL = idR after renaming,
+ -- but these need to be idL's for the collect... code in HsUtil to have
+ -- the right type
+ abs_exports :: [([TyVar], idL, idL, [LPrag])], -- (tvs, poly_id, mono_id, prags)
+ abs_binds :: LHsBinds idL -- The dictionary bindings and typechecked user bindings
-- mixed up together; you can tell the dict bindings because
-- they are all VarBinds
}
placeHolderNames = panic "placeHolderNames"
------------
-instance OutputableBndr id => Outputable (HsLocalBinds id) where
+instance (OutputableBndr idL, OutputableBndr idR) => Outputable (HsLocalBindsLR idL idR) where
ppr (HsValBinds bs) = ppr bs
ppr (HsIPBinds bs) = ppr bs
ppr EmptyLocalBinds = empty
-instance OutputableBndr id => Outputable (HsValBinds id) where
+instance (OutputableBndr idL, OutputableBndr idR) => Outputable (HsValBindsLR idL idR) where
ppr (ValBindsIn binds sigs)
= pprValBindsForUser binds sigs
-- 'where' include a list of HsBindGroups and we don't want
-- several groups of bindings each with braces around.
-- Sort by location before printing
-pprValBindsForUser :: (OutputableBndr id1, OutputableBndr id2)
- => LHsBinds id1 -> [LSig id2] -> SDoc
+pprValBindsForUser :: (OutputableBndr idL, OutputableBndr idR, OutputableBndr id2)
+ => LHsBindsLR idL idR -> [LSig id2] -> SDoc
pprValBindsForUser binds sigs
- = vcat (map snd (sort_by_loc decls))
+ = pprDeeperList vcat (map snd (sort_by_loc decls))
where
decls :: [(SrcSpan, SDoc)]
decls = [(loc, ppr sig) | L loc sig <- sigs] ++
- [(loc, ppr bind) | L loc bind <- bagToList binds]
+ [(loc, ppr bind) | L loc bind <- bagToList binds]
sort_by_loc decls = sortLe (\(l1,_) (l2,_) -> l1 <= l2) decls
-pprLHsBinds :: OutputableBndr id => LHsBinds id -> SDoc
+pprLHsBinds :: (OutputableBndr idL, OutputableBndr idR) => LHsBindsLR idL idR -> SDoc
pprLHsBinds binds
| isEmptyLHsBinds binds = empty
- | otherwise = lbrace <+> vcat (map ppr (bagToList binds)) <+> rbrace
+ | otherwise = lbrace <+> pprDeeperList vcat (map ppr (bagToList binds)) <+> rbrace
------------
-emptyLocalBinds :: HsLocalBinds a
+emptyLocalBinds :: HsLocalBindsLR a b
emptyLocalBinds = EmptyLocalBinds
-isEmptyLocalBinds :: HsLocalBinds a -> Bool
+isEmptyLocalBinds :: HsLocalBindsLR a b -> Bool
isEmptyLocalBinds (HsValBinds ds) = isEmptyValBinds ds
isEmptyLocalBinds (HsIPBinds ds) = isEmptyIPBinds ds
isEmptyLocalBinds EmptyLocalBinds = True
-isEmptyValBinds :: HsValBinds a -> Bool
+isEmptyValBinds :: HsValBindsLR a b -> Bool
isEmptyValBinds (ValBindsIn ds sigs) = isEmptyLHsBinds ds && null sigs
isEmptyValBinds (ValBindsOut ds sigs) = null ds && null sigs
-emptyValBindsIn, emptyValBindsOut :: HsValBinds a
+emptyValBindsIn, emptyValBindsOut :: HsValBindsLR a b
emptyValBindsIn = ValBindsIn emptyBag []
emptyValBindsOut = ValBindsOut [] []
-emptyLHsBinds :: LHsBinds id
+emptyLHsBinds :: LHsBindsLR idL idR
emptyLHsBinds = emptyBag
-isEmptyLHsBinds :: LHsBinds id -> Bool
+isEmptyLHsBinds :: LHsBindsLR idL idR -> Bool
isEmptyLHsBinds = isEmptyBag
------------
in (fm,gm)
\begin{code}
-instance OutputableBndr id => Outputable (HsBind id) where
+instance (OutputableBndr idL, OutputableBndr idR) => Outputable (HsBindLR idL idR) where
ppr mbind = ppr_monobind mbind
-ppr_monobind :: OutputableBndr id => HsBind id -> SDoc
+ppr_monobind :: (OutputableBndr idL, OutputableBndr idR) => HsBindLR idL idR -> SDoc
ppr_monobind (PatBind { pat_lhs = pat, pat_rhs = grhss }) = pprPatBind pat grhss
ppr_monobind (VarBind { var_id = var, var_rhs = rhs }) = ppr var <+> equals <+> pprExpr (unLoc rhs)
-ppr_monobind (FunBind { fun_id = fun, fun_matches = matches }) = pprFunBind (unLoc fun) matches
- -- ToDo: print infix if appropriate
+ppr_monobind (FunBind { fun_id = fun, fun_infix = inf,
+ fun_matches = matches,
+ fun_tick = tick }) =
+ (case tick of
+ Nothing -> empty
+ Just t -> text "-- tick id = " <> ppr t
+ ) $$ pprFunBind (unLoc fun) inf matches
ppr_monobind (AbsBinds { abs_tvs = tyvars, abs_dicts = dictvars,
abs_exports = exports, abs_binds = val_binds })
(LHsExpr id)
instance (OutputableBndr id) => Outputable (HsIPBinds id) where
- ppr (IPBinds bs ds) = vcat (map ppr bs)
+ ppr (IPBinds bs ds) = pprDeeperList vcat (map ppr bs)
$$ pprLHsBinds ds
instance (OutputableBndr id) => Outputable (IPBind id) where
| WpCo Coercion -- A cast: [] `cast` co
-- Guaranteedn not the identity coercion
- | WpApp Var -- [] x; the xi are dicts or coercions
- | WpTyApp Type -- [] t
- | WpLam Id -- \x. []; the xi are dicts or coercions
- | WpTyLam TyVar -- \a. []
+ | WpApp Var -- [] d the 'd' is a type-class dictionary
+ | WpTyApp Type -- [] t the 't' is a type or corecion
+ | WpLam Id -- \d. [] the 'd' is a type-class dictionary
+ | WpTyLam TyVar -- \a. [] the 'a' is a type or coercion variable
-- Non-empty bindings, so that the identity coercion
-- is always exactly WpHole
ppr co_fn = pprHsWrapper (ptext SLIT("<>")) co_fn
pprHsWrapper :: SDoc -> HsWrapper -> SDoc
-pprHsWrapper it WpHole = it
-pprHsWrapper it (WpCompose f1 f2) = pprHsWrapper (pprHsWrapper it f2) f1
-pprHsWrapper it (WpCo co) = it <+> ptext SLIT("`cast`") <+> pprParendType co
-pprHsWrapper it (WpApp id) = it <+> ppr id
-pprHsWrapper it (WpTyApp ty) = it <+> ptext SLIT("@") <+> pprParendType ty
-pprHsWrapper it (WpLam id) = ptext SLIT("\\") <> pprBndr LambdaBind id <> dot <+> it
-pprHsWrapper it (WpTyLam tv) = ptext SLIT("/\\") <> pprBndr LambdaBind tv <> dot <+> it
-pprHsWrapper it (WpLet binds) = sep [ptext SLIT("let") <+> braces (ppr binds), it]
+pprHsWrapper it wrap =
+ let
+ help it WpHole = it
+ help it (WpCompose f1 f2) = help (help it f2) f1
+ help it (WpCo co) = sep [it, nest 2 (ptext SLIT("`cast`") <+> pprParendType co)]
+ help it (WpApp id) = sep [it, nest 2 (ppr id)]
+ help it (WpTyApp ty) = sep [it, ptext SLIT("@") <+> pprParendType ty]
+ help it (WpLam id) = sep [ptext SLIT("\\") <> pprBndr LambdaBind id <> dot, it]
+ help it (WpTyLam tv) = sep [ptext SLIT("/\\") <> pprBndr LambdaBind tv <> dot, it]
+ help it (WpLet binds) = sep [ptext SLIT("let") <+> braces (ppr binds), it]
+ in
+ -- in debug mode, print the wrapper
+ -- otherwise just print what's inside
+ getPprStyle (\ s -> if debugStyle s then (help it wrap) else it)
(<.>) :: HsWrapper -> HsWrapper -> HsWrapper
WpHole <.> c = c
\begin{code}
type LSig name = Located (Sig name)
-data Sig name
- = TypeSig (Located name) -- A bog-std type signature
+data Sig name -- Signatures and pragmas
+ = -- An ordinary type signature
+ -- f :: Num a => a -> a
+ TypeSig (Located name) -- A bog-std type signature
(LHsType name)
- | SpecSig (Located name) -- Specialise a function or datatype ...
- (LHsType name) -- ... to these types
- InlineSpec
+ -- An ordinary fixity declaration
+ -- infixl *** 8
+ | FixSig (FixitySig name) -- Fixity declaration
+ -- An inline pragma
+ -- {#- INLINE f #-}
| InlineSig (Located name) -- Function name
InlineSpec
+ -- A specialisation pragma
+ -- {-# SPECIALISE f :: Int -> Int #-}
+ | SpecSig (Located name) -- Specialise a function or datatype ...
+ (LHsType name) -- ... to these types
+ InlineSpec
+
+ -- A specialisation pragma for instance declarations only
+ -- {-# SPECIALISE instance Eq [Int] #-}
| SpecInstSig (LHsType name) -- (Class tys); should be a specialisation of the
-- current instance decl
- | FixSig (FixitySig name) -- Fixity declaration
type LFixitySig name = Located (FixitySig name)
data FixitySig name = FixitySig (Located name) Fixity
-- A Prag conveys pragmas from the type checker to the desugarer
+type LPrag = Located Prag
data Prag
= InlinePrag
InlineSpec
(HsExpr Id) -- An expression, of the given specialised type, which
PostTcType -- specialises the polymorphic function
[Id] -- Dicts mentioned free in the expression
+ -- Apr07: I think this is pretty useless
+ -- see Note [Const rule dicts] in DsBinds
InlineSpec -- Inlining spec for the specialised function
isInlinePrag (InlinePrag _) = True
isInlinePrag prag = False
-isSpecPrag (SpecPrag _ _ _ _) = True
-isSpecPrag prag = False
+isSpecPrag (SpecPrag {}) = True
+isSpecPrag prag = False
\end{code}
\begin{code}
Just n -> n `elemNameSet` ns
sigName :: LSig name -> Maybe name
-sigName (L _ sig) = f sig
- where
- f (TypeSig n _) = Just (unLoc n)
- f (SpecSig n _ _) = Just (unLoc n)
- f (InlineSig n _) = Just (unLoc n)
- f (FixSig (FixitySig n _)) = Just (unLoc n)
- f other = Nothing
+sigName (L _ sig) = sigNameNoLoc sig
+
+sigNameNoLoc :: Sig name -> Maybe name
+sigNameNoLoc (TypeSig n _) = Just (unLoc n)
+sigNameNoLoc (SpecSig n _ _) = Just (unLoc n)
+sigNameNoLoc (InlineSig n _) = Just (unLoc n)
+sigNameNoLoc (FixSig (FixitySig n _)) = Just (unLoc n)
+sigNameNoLoc other = Nothing
isFixityLSig :: LSig name -> Bool
isFixityLSig (L _ (FixSig {})) = True
pprSpec :: (Outputable id, Outputable ty) => id -> ty -> InlineSpec -> SDoc
pprSpec var ty inl = sep [ptext SLIT("SPECIALIZE") <+> ppr inl <+> pprVarSig var ty]
-pprPrag :: Outputable id => id -> Prag -> SDoc
-pprPrag var (InlinePrag inl) = ppr inl <+> ppr var
-pprPrag var (SpecPrag expr ty _ inl) = pprSpec var ty inl
+pprPrag :: Outputable id => id -> LPrag -> SDoc
+pprPrag var (L _ (InlinePrag inl)) = ppr inl <+> ppr var
+pprPrag var (L _ (SpecPrag expr ty _ inl)) = pprSpec var ty inl
\end{code}
+
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