{-
(c) The University of Glasgow 2006
(c) The GRASP/AQUA Project, Glasgow University, 1992-1998
-}{-# LANGUAGE DeriveDataTypeable #-}{-# LANGUAGE BangPatterns #-}{-# LANGUAGE OverloadedStrings #-}-- |-- #name_types#-- GHC uses several kinds of name internally:---- * 'OccName.OccName' represents names as strings with just a little more information:-- the \"namespace\" that the name came from, e.g. the namespace of value, type constructors or-- data constructors---- * 'RdrName.RdrName': see "RdrName#name_types"---- * 'Name.Name': see "Name#name_types"---- * 'Id.Id': see "Id#name_types"---- * 'Var.Var': see "Var#name_types"moduleOccName(-- * The 'NameSpace' typeNameSpace ,-- AbstractnameSpacesRelated ,-- ** Construction-- $real_vs_source_data_constructorstcName ,clsName ,tcClsName ,dataName ,varName ,tvName ,srcDataName ,-- ** Pretty PrintingpprNameSpace ,pprNonVarNameSpace ,pprNameSpaceBrief ,-- * The 'OccName' typeOccName ,-- Abstract, instance of OutputablepprOccName ,-- ** ConstructionmkOccName ,mkOccNameFS ,mkVarOcc ,mkVarOccFS ,mkDataOcc ,mkDataOccFS ,mkTyVarOcc ,mkTyVarOccFS ,mkTcOcc ,mkTcOccFS ,mkClsOcc ,mkClsOccFS ,mkDFunOcc ,setOccNameSpace ,demoteOccName ,HasOccName (..),-- ** Derived 'OccName'sisDerivedOccName ,mkDataConWrapperOcc ,mkWorkerOcc ,mkMatcherOcc ,mkBuilderOcc ,mkDefaultMethodOcc ,isDefaultMethodOcc ,isTypeableBindOcc ,mkNewTyCoOcc ,mkClassOpAuxOcc ,mkCon2TagOcc ,mkTag2ConOcc ,mkMaxTagOcc ,mkClassDataConOcc ,mkDictOcc ,mkIPOcc ,mkSpecOcc ,mkForeignExportOcc ,mkRepEqOcc ,mkGenR ,mkGen1R ,mkDataTOcc ,mkDataCOcc ,mkDataConWorkerOcc ,mkSuperDictSelOcc ,mkSuperDictAuxOcc ,mkLocalOcc ,mkMethodOcc ,mkInstTyTcOcc ,mkInstTyCoOcc ,mkEqPredCoOcc ,mkRecFldSelOcc ,mkTyConRepOcc ,-- ** DeconstructionoccNameFS ,occNameString ,occNameSpace ,isVarOcc ,isTvOcc ,isTcOcc ,isDataOcc ,isDataSymOcc ,isSymOcc ,isValOcc ,parenSymOcc ,startsWithUnderscore ,isTcClsNameSpace ,isTvNameSpace ,isDataConNameSpace ,isVarNameSpace ,isValNameSpace ,-- * The 'OccEnv' typeOccEnv ,emptyOccEnv ,unitOccEnv ,extendOccEnv ,mapOccEnv ,lookupOccEnv ,mkOccEnv ,mkOccEnv_C ,extendOccEnvList ,elemOccEnv ,occEnvElts ,foldOccEnv ,plusOccEnv ,plusOccEnv_C ,extendOccEnv_C ,extendOccEnv_Acc ,filterOccEnv ,delListFromOccEnv ,delFromOccEnv ,alterOccEnv ,pprOccEnv ,-- * The 'OccSet' typeOccSet ,emptyOccSet ,unitOccSet ,mkOccSet ,extendOccSet ,extendOccSetList ,unionOccSets ,unionManyOccSets ,minusOccSet ,elemOccSet ,isEmptyOccSet ,intersectOccSet ,intersectsOccSet ,filterOccSet ,-- * Tidying upTidyOccEnv ,emptyTidyOccEnv ,initTidyOccEnv ,tidyOccName ,avoidClashesOccEnv ,-- FsEnvFastStringEnv ,emptyFsEnv ,lookupFsEnv ,extendFsEnv ,mkFsEnv )whereimportGhcPrelude importUtil importUnique importDynFlags importUniqFM importUniqSet importFastString importFastStringEnv importOutputable importLexeme importBinary importControl.DeepSeqimportData.CharimportData.Data{-
************************************************************************
* *
\subsection{Name space}
* *
************************************************************************
-}dataNameSpace =VarName -- Variables, including "real" data constructors|DataName -- "Source" data constructors|TvName -- Type variables|TcClsName -- Type constructors and classes; Haskell has them-- in the same name space for now.deriving(Eq,Ord)-- Note [Data Constructors]-- see also: Note [Data Constructor Naming] in DataCon.hs---- $real_vs_source_data_constructors-- There are two forms of data constructor:---- [Source data constructors] The data constructors mentioned in Haskell source code---- [Real data constructors] The data constructors of the representation type, which may not be the same as the source type---- For example:---- > data T = T !(Int, Int)---- The source datacon has type @(Int, Int) -> T@-- The real datacon has type @Int -> Int -> T@---- GHC chooses a representation based on the strictness etc.tcName,clsName,tcClsName::NameSpace dataName,srcDataName::NameSpace tvName,varName::NameSpace -- Though type constructors and classes are in the same name space now,-- the NameSpace type is abstract, so we can easily separate them latertcName =TcClsName -- Type constructorsclsName =TcClsName -- ClassestcClsName =TcClsName -- Not sure which!dataName =DataName srcDataName =DataName -- Haskell-source data constructors should be-- in the Data name spacetvName =TvName varName =VarName isDataConNameSpace::NameSpace ->BoolisDataConNameSpace DataName =TrueisDataConNameSpace_=FalseisTcClsNameSpace::NameSpace ->BoolisTcClsNameSpace TcClsName =TrueisTcClsNameSpace_=FalseisTvNameSpace::NameSpace ->BoolisTvNameSpace TvName =TrueisTvNameSpace_=FalseisVarNameSpace::NameSpace ->Bool-- Variables or type variables, but not constructorsisVarNameSpace TvName =TrueisVarNameSpaceVarName =TrueisVarNameSpace_=FalseisValNameSpace::NameSpace ->BoolisValNameSpace DataName =TrueisValNameSpaceVarName =TrueisValNameSpace_=FalsepprNameSpace::NameSpace ->SDoc pprNameSpace DataName =text "data constructor"pprNameSpaceVarName =text "variable"pprNameSpaceTvName =text "type variable"pprNameSpaceTcClsName =text "type constructor or class"pprNonVarNameSpace::NameSpace ->SDoc pprNonVarNameSpace VarName =empty pprNonVarNameSpacens =pprNameSpace ns pprNameSpaceBrief::NameSpace ->SDoc pprNameSpaceBrief DataName =char 'd'pprNameSpaceBriefVarName =char 'v'pprNameSpaceBriefTvName =text "tv"pprNameSpaceBriefTcClsName =text "tc"-- demoteNameSpace lowers the NameSpace if possible. We can not know-- in advance, since a TvName can appear in an HsTyVar.-- See Note [Demotion] in RnEnvdemoteNameSpace::NameSpace ->MaybeNameSpace demoteNameSpace VarName =NothingdemoteNameSpaceDataName =NothingdemoteNameSpaceTvName =NothingdemoteNameSpaceTcClsName =JustDataName {-
************************************************************************
* *
\subsection[Name-pieces-datatypes]{The @OccName@ datatypes}
* *
************************************************************************
-}-- | Occurrence Name---- In this context that means:-- "classified (i.e. as a type name, value name, etc) but not qualified-- and not yet resolved"dataOccName =OccName {occNameSpace ::!NameSpace ,occNameFS ::!FastString }instanceEqOccName where(OccName sp1 s1 )== (OccName sp2 s2 )=s1 ==s2 &&sp1 ==sp2 instanceOrdOccName where-- Compares lexicographically, *not* by Unique of the stringcompare (OccName sp1 s1 )(OccName sp2 s2 )=(s1 `compare`s2 )`thenCmp `(sp1 `compare`sp2 )instanceDataOccName where-- don't traverse?toConstr _=abstractConstr "OccName"gunfold __=error"gunfold"dataTypeOf _=mkNoRepType"OccName"instanceHasOccName OccName whereoccName =idinstanceNFDataOccName wherernf x =x `seq`(){-
************************************************************************
* *
\subsection{Printing}
* *
************************************************************************
-}instanceOutputable OccName whereppr =pprOccName instanceOutputableBndr OccName wherepprBndr _=ppr pprInfixOcc n =pprInfixVar (isSymOcc n )(ppr n )pprPrefixOcc n =pprPrefixVar (isSymOcc n )(ppr n )pprOccName::OccName ->SDoc pprOccName (OccName sp occ )=getPprStyle $\sty ->ifcodeStyle sty thenztext (zEncodeFS occ )elsepp_occ <> pp_debug sty wherepp_debug sty |debugStyle sty =braces (pprNameSpaceBrief sp )|otherwise=empty pp_occ =sdocWithDynFlags $\dflags ->ifgopt Opt_SuppressUniques dflags thentext (strip_th_unique (unpackFS occ ))elseftext occ -- See Note [Suppressing uniques in OccNames]strip_th_unique ('[':c :_)|isAlphaNumc =[]strip_th_unique(c :cs )=c :strip_th_unique cs strip_th_unique[]=[]{-
Note [Suppressing uniques in OccNames]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This is a hack to de-wobblify the OccNames that contain uniques from
Template Haskell that have been turned into a string in the OccName.
See Note [Unique OccNames from Template Haskell] in Convert.hs
************************************************************************
* *
\subsection{Construction}
* *
************************************************************************
-}mkOccName::NameSpace ->String->OccName mkOccName occ_sp str =OccName occ_sp (mkFastString str )mkOccNameFS::NameSpace ->FastString ->OccName mkOccNameFS occ_sp fs =OccName occ_sp fs mkVarOcc::String->OccName mkVarOcc s =mkOccName varName s mkVarOccFS::FastString ->OccName mkVarOccFS fs =mkOccNameFS varName fs mkDataOcc::String->OccName mkDataOcc =mkOccName dataName mkDataOccFS::FastString ->OccName mkDataOccFS =mkOccNameFS dataName mkTyVarOcc::String->OccName mkTyVarOcc =mkOccName tvName mkTyVarOccFS::FastString ->OccName mkTyVarOccFS fs =mkOccNameFS tvName fs mkTcOcc::String->OccName mkTcOcc =mkOccName tcName mkTcOccFS::FastString ->OccName mkTcOccFS =mkOccNameFS tcName mkClsOcc::String->OccName mkClsOcc =mkOccName clsName mkClsOccFS::FastString ->OccName mkClsOccFS =mkOccNameFS clsName -- demoteOccName lowers the Namespace of OccName.-- see Note [Demotion]demoteOccName::OccName ->MaybeOccName demoteOccName (OccName space name )=dospace' <-demoteNameSpace space return$OccName space' name -- Name spaces are related if there is a chance to mean the one when one writes-- the other, i.e. variables <-> data constructors and type variables <-> type constructorsnameSpacesRelated::NameSpace ->NameSpace ->BoolnameSpacesRelated ns1 ns2 =ns1 ==ns2 ||otherNameSpace ns1 ==ns2 otherNameSpace::NameSpace ->NameSpace otherNameSpace VarName =DataName otherNameSpaceDataName =VarName otherNameSpaceTvName =TcClsName otherNameSpaceTcClsName =TvName {- | Other names in the compiler add additional information to an OccName.
This class provides a consistent way to access the underlying OccName. -}classHasOccName name whereoccName ::name ->OccName {-
************************************************************************
* *
 Environments
* *
************************************************************************
OccEnvs are used mainly for the envts in ModIfaces.
Note [The Unique of an OccName]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
They are efficient, because FastStrings have unique Int# keys. We assume
this key is less than 2^24, and indeed FastStrings are allocated keys
sequentially starting at 0.
So we can make a Unique using
 mkUnique ns key :: Unique
where 'ns' is a Char representing the name space. This in turn makes it
easy to build an OccEnv.
-}instanceUniquable OccName where-- See Note [The Unique of an OccName]getUnique (OccName VarName fs )=mkVarOccUnique fs getUnique(OccName DataName fs )=mkDataOccUnique fs getUnique(OccName TvName fs )=mkTvOccUnique fs getUnique(OccName TcClsName fs )=mkTcOccUnique fs newtypeOccEnv a =A (UniqFM a )derivingDataemptyOccEnv::OccEnv a unitOccEnv::OccName ->a ->OccEnv a extendOccEnv::OccEnv a ->OccName ->a ->OccEnv a extendOccEnvList::OccEnv a ->[(OccName ,a )]->OccEnv a lookupOccEnv::OccEnv a ->OccName ->Maybea mkOccEnv::[(OccName ,a )]->OccEnv a mkOccEnv_C::(a ->a ->a )->[(OccName ,a )]->OccEnv a elemOccEnv::OccName ->OccEnv a ->BoolfoldOccEnv::(a ->b ->b )->b ->OccEnv a ->b occEnvElts::OccEnv a ->[a ]extendOccEnv_C::(a ->a ->a )->OccEnv a ->OccName ->a ->OccEnv a extendOccEnv_Acc::(a ->b ->b )->(a ->b )->OccEnv b ->OccName ->a ->OccEnv b plusOccEnv::OccEnv a ->OccEnv a ->OccEnv a plusOccEnv_C::(a ->a ->a )->OccEnv a ->OccEnv a ->OccEnv a mapOccEnv::(a ->b )->OccEnv a ->OccEnv b delFromOccEnv::OccEnv a ->OccName ->OccEnv a delListFromOccEnv::OccEnv a ->[OccName ]->OccEnv a filterOccEnv::(elt ->Bool)->OccEnv elt ->OccEnv elt alterOccEnv::(Maybeelt ->Maybeelt )->OccEnv elt ->OccName ->OccEnv elt emptyOccEnv =A emptyUFM unitOccEnv x y =A $unitUFM x y extendOccEnv (A x )y z =A $addToUFM x y z extendOccEnvList (A x )l =A $addListToUFM x l lookupOccEnv (A x )y =lookupUFM x y mkOccEnv l =A $listToUFM l elemOccEnv x (A y )=elemUFM x y foldOccEnv a b (A c )=foldUFM a b c occEnvElts (A x )=eltsUFM x plusOccEnv (A x )(A y )=A $plusUFM x y plusOccEnv_C f (A x )(A y )=A $plusUFM_C f x y extendOccEnv_C f (A x )y z =A $addToUFM_C f x y z extendOccEnv_Acc f g (A x )y z =A $addToUFM_Acc f g x y z mapOccEnv f (A x )=A $mapUFM f x mkOccEnv_C comb l =A $addListToUFM_C comb emptyUFM l delFromOccEnv (A x )y =A $delFromUFM x y delListFromOccEnv (A x )y =A $delListFromUFM x y filterOccEnv x (A y )=A $filterUFM x y alterOccEnv fn (A y )k =A $alterUFM fn y k instanceOutputable a =>Outputable (OccEnv a )whereppr x =pprOccEnv ppr x pprOccEnv::(a ->SDoc )->OccEnv a ->SDoc pprOccEnv ppr_elt (A env )=pprUniqFM ppr_elt env typeOccSet =UniqSet OccName emptyOccSet::OccSet unitOccSet::OccName ->OccSet mkOccSet::[OccName ]->OccSet extendOccSet::OccSet ->OccName ->OccSet extendOccSetList::OccSet ->[OccName ]->OccSet unionOccSets::OccSet ->OccSet ->OccSet unionManyOccSets::[OccSet ]->OccSet minusOccSet::OccSet ->OccSet ->OccSet elemOccSet::OccName ->OccSet ->BoolisEmptyOccSet::OccSet ->BoolintersectOccSet::OccSet ->OccSet ->OccSet intersectsOccSet::OccSet ->OccSet ->BoolfilterOccSet::(OccName ->Bool)->OccSet ->OccSet emptyOccSet =emptyUniqSet unitOccSet =unitUniqSet mkOccSet =mkUniqSet extendOccSet =addOneToUniqSet extendOccSetList =addListToUniqSet unionOccSets =unionUniqSets unionManyOccSets =unionManyUniqSets minusOccSet =minusUniqSet elemOccSet =elementOfUniqSet isEmptyOccSet =isEmptyUniqSet intersectOccSet =intersectUniqSets intersectsOccSet s1 s2 =not(isEmptyOccSet (s1 `intersectOccSet `s2 ))filterOccSet =filterUniqSet {-
************************************************************************
* *
\subsection{Predicates and taking them apart}
* *
************************************************************************
-}occNameString::OccName ->StringoccNameString (OccName _s )=unpackFS s setOccNameSpace::NameSpace ->OccName ->OccName setOccNameSpace sp (OccName _occ )=OccName sp occ isVarOcc,isTvOcc,isTcOcc,isDataOcc::OccName ->BoolisVarOcc (OccName VarName _)=TrueisVarOcc_=FalseisTvOcc (OccName TvName _)=TrueisTvOcc_=FalseisTcOcc (OccName TcClsName _)=TrueisTcOcc_=False-- | /Value/ 'OccNames's are those that are either in-- the variable or data constructor namespacesisValOcc::OccName ->BoolisValOcc (OccName VarName _)=TrueisValOcc(OccName DataName _)=TrueisValOcc_=FalseisDataOcc (OccName DataName _)=TrueisDataOcc_=False-- | Test if the 'OccName' is a data constructor that starts with-- a symbol (e.g. @:@, or @[]@)isDataSymOcc::OccName ->BoolisDataSymOcc (OccName DataName s )=isLexConSym s isDataSymOcc_=False-- Pretty inefficient!-- | Test if the 'OccName' is that for any operator (whether-- it is a data constructor or variable or whatever)isSymOcc::OccName ->BoolisSymOcc (OccName DataName s )=isLexConSym s isSymOcc(OccName TcClsName s )=isLexSym s isSymOcc(OccName VarName s )=isLexSym s isSymOcc(OccName TvName s )=isLexSym s -- Pretty inefficient!parenSymOcc::OccName ->SDoc ->SDoc -- ^ Wrap parens around an operatorparenSymOcc occ doc |isSymOcc occ =parens doc |otherwise=doc startsWithUnderscore::OccName ->Bool-- ^ Haskell 98 encourages compilers to suppress warnings about unsed-- names in a pattern if they start with @_@: this implements that teststartsWithUnderscore occ =headFS (occNameFSocc )=='_'{-
************************************************************************
* *
\subsection{Making system names}
* *
************************************************************************
Here's our convention for splitting up the interface file name space:
 d... dictionary identifiers
 (local variables, so no name-clash worries)
All of these other OccNames contain a mixture of alphabetic
and symbolic characters, and hence cannot possibly clash with
a user-written type or function name
 $f... Dict-fun identifiers (from inst decls)
 $dmop Default method for 'op'
 $pnC n'th superclass selector for class C
 $wf Worker for function 'f'
 $sf.. Specialised version of f
 D:C Data constructor for dictionary for class C
 NTCo:T Coercion connecting newtype T with its representation type
 TFCo:R Coercion connecting a data family to its representation type R
In encoded form these appear as Zdfxxx etc
 :... keywords (export:, letrec: etc.)
--- I THINK THIS IS WRONG!
This knowledge is encoded in the following functions.
@mk_deriv@ generates an @OccName@ from the prefix and a string.
NB: The string must already be encoded!
-}-- | Build an 'OccName' derived from another 'OccName'.---- Note that the pieces of the name are passed in as a @[FastString]@ so that-- the whole name can be constructed with a single 'concatFS', minimizing-- unnecessary intermediate allocations.mk_deriv::NameSpace ->FastString -- ^ A prefix which distinguishes one sort of-- derived name from another->[FastString ]-- ^ The name we are deriving from in pieces which-- will be concatenated.->OccName mk_deriv occ_sp sys_prefix str =mkOccNameFS occ_sp (concatFS $sys_prefix :str )isDerivedOccName::OccName ->Bool-- ^ Test for definitions internally generated by GHC. This predicte-- is used to suppress printing of internal definitions in some debug printsisDerivedOccName occ =caseoccNameString occ of'$':c :_|isAlphaNumc ->True-- E.g. $wfooc :':':_|isAlphaNumc ->True-- E.g. N:blah newtype coercions_other ->FalseisDefaultMethodOcc::OccName ->BoolisDefaultMethodOcc occ =caseoccNameString occ of'$':'d':'m':_->True_->False-- | Is an 'OccName' one of a Typeable @TyCon@ or @Module@ binding?-- This is needed as these bindings are renamed differently.-- See Note [Grand plan for Typeable] in TcTypeable.isTypeableBindOcc::OccName ->BoolisTypeableBindOcc occ =caseoccNameString occ of'$':'t':'c':_->True-- mkTyConRepOcc'$':'t':'r':_->True-- Module binding_->FalsemkDataConWrapperOcc,mkWorkerOcc,mkMatcherOcc,mkBuilderOcc,mkDefaultMethodOcc,mkClassDataConOcc,mkDictOcc,mkIPOcc,mkSpecOcc,mkForeignExportOcc,mkRepEqOcc,mkGenR,mkGen1R,mkDataConWorkerOcc,mkNewTyCoOcc,mkInstTyCoOcc,mkEqPredCoOcc,mkClassOpAuxOcc,mkCon2TagOcc,mkTag2ConOcc,mkMaxTagOcc,mkTyConRepOcc::OccName ->OccName -- These derived variables have a prefix that no Haskell value could havemkDataConWrapperOcc =mk_simple_deriv varName "$W"mkWorkerOcc =mk_simple_deriv varName "$w"mkMatcherOcc =mk_simple_deriv varName "$m"mkBuilderOcc =mk_simple_deriv varName "$b"mkDefaultMethodOcc =mk_simple_deriv varName "$dm"mkClassOpAuxOcc =mk_simple_deriv varName "$c"mkDictOcc =mk_simple_deriv varName "$d"mkIPOcc =mk_simple_deriv varName "$i"mkSpecOcc =mk_simple_deriv varName "$s"mkForeignExportOcc =mk_simple_deriv varName "$f"mkRepEqOcc =mk_simple_deriv tvName "$r"-- In RULES involving CoerciblemkClassDataConOcc =mk_simple_deriv dataName "C:"-- Data con for a classmkNewTyCoOcc =mk_simple_deriv tcName "N:"-- Coercion for newtypesmkInstTyCoOcc =mk_simple_deriv tcName "D:"-- Coercion for type functionsmkEqPredCoOcc =mk_simple_deriv tcName "$co"-- Used in derived instancesmkCon2TagOcc =mk_simple_deriv varName "$con2tag_"mkTag2ConOcc =mk_simple_deriv varName "$tag2con_"mkMaxTagOcc =mk_simple_deriv varName "$maxtag_"-- TyConRepName stuff; see Note [Grand plan for Typeable] in TcTypeablemkTyConRepOcc occ =mk_simple_deriv varName prefix occ whereprefix |isDataOcc occ ="$tc'"|otherwise="$tc"-- Generic deriving mechanismmkGenR =mk_simple_deriv tcName "Rep_"mkGen1R =mk_simple_deriv tcName "Rep1_"-- Overloaded record field selectorsmkRecFldSelOcc::String->OccName mkRecFldSelOcc s =mk_deriv varName "$sel"[fsLit s ]mk_simple_deriv::NameSpace ->FastString ->OccName ->OccName mk_simple_deriv sp px occ =mk_deriv sp px [occNameFSocc ]-- Data constructor workers are made by setting the name space-- of the data constructor OccName (which should be a DataName)-- to VarNamemkDataConWorkerOcc datacon_occ =setOccNameSpace varName datacon_occ mkSuperDictAuxOcc::Int->OccName ->OccName mkSuperDictAuxOcc index cls_tc_occ =mk_deriv varName "$cp"[fsLit $showindex ,occNameFScls_tc_occ ]mkSuperDictSelOcc::Int-- ^ Index of superclass, e.g. 3->OccName -- ^ Class, e.g. @Ord@->OccName -- ^ Derived 'Occname', e.g. @$p3Ord@mkSuperDictSelOcc index cls_tc_occ =mk_deriv varName "$p"[fsLit $showindex ,occNameFScls_tc_occ ]mkLocalOcc::Unique -- ^ Unique to combine with the 'OccName'->OccName -- ^ Local name, e.g. @sat@->OccName -- ^ Nice unique version, e.g. @$L23sat@mkLocalOcc uniq occ =mk_deriv varName "$L"[fsLit $showuniq ,occNameFSocc ]-- The Unique might print with characters-- that need encoding (e.g. 'z'!)-- | Derive a name for the representation type constructor of a-- @data@\/@newtype@ instance.mkInstTyTcOcc::String-- ^ Family name, e.g. @Map@->OccSet -- ^ avoid these Occs->OccName -- ^ @R:Map@mkInstTyTcOcc str =chooseUniqueOcc tcName ('R':':':str )mkDFunOcc::String-- ^ Typically the class and type glommed together e.g. @OrdMaybe@.-- Only used in debug mode, for extra clarity->Bool-- ^ Is this a hs-boot instance DFun?->OccSet -- ^ avoid these Occs->OccName -- ^ E.g. @$f3OrdMaybe@-- In hs-boot files we make dict funs like $fx7ClsTy, which get bound to the real-- thing when we compile the mother module. Reason: we don't know exactly-- what the mother module will call it.mkDFunOcc info_str is_boot set =chooseUniqueOcc VarName (prefix ++info_str )set whereprefix |is_boot ="$fx"|otherwise="$f"mkDataTOcc,mkDataCOcc::OccName -- ^ TyCon or data con string->OccSet -- ^ avoid these Occs->OccName -- ^ E.g. @$f3OrdMaybe@-- data T = MkT ... deriving( Data ) needs definitions for-- $tT :: Data.Generics.Basics.DataType-- $cMkT :: Data.Generics.Basics.ConstrmkDataTOcc occ =chooseUniqueOcc VarName ("$t"++occNameString occ )mkDataCOcc occ =chooseUniqueOcc VarName ("$c"++occNameString occ ){-
Sometimes we need to pick an OccName that has not already been used,
given a set of in-use OccNames.
-}chooseUniqueOcc::NameSpace ->String->OccSet ->OccName chooseUniqueOcc ns str set =loop (mkOccName ns str )(0::Int)whereloop occ n |occ `elemOccSet `set =loop (mkOccName ns (str ++shown ))(n +1)|otherwise=occ {-
We used to add a '$m' to indicate a method, but that gives rise to bad
error messages from the type checker when we print the function name or pattern
of an instance-decl binding. Why? Because the binding is zapped
to use the method name in place of the selector name.
(See TcClassDcl.tcMethodBind)
The way it is now, -ddump-xx output may look confusing, but
you can always say -dppr-debug to get the uniques.
However, we *do* have to zap the first character to be lower case,
because overloaded constructors (blarg) generate methods too.
And convert to VarName space
e.g. a call to constructor MkFoo where
 data (Ord a) => Foo a = MkFoo a
If this is necessary, we do it by prefixing '$m'. These
guys never show up in error messages. What a hack.
-}mkMethodOcc::OccName ->OccName mkMethodOcc occ @(OccName VarName _)=occ mkMethodOccocc =mk_simple_deriv varName "$m"occ {-
************************************************************************
* *
\subsection{Tidying them up}
* *
************************************************************************
Before we print chunks of code we like to rename it so that
we don't have to print lots of silly uniques in it. But we mustn't
accidentally introduce name clashes! So the idea is that we leave the
OccName alone unless it accidentally clashes with one that is already
in scope; if so, we tack on '1' at the end and try again, then '2', and
so on till we find a unique one.
There's a wrinkle for operators. Consider '>>='. We can't use '>>=1'
because that isn't a single lexeme. So we encode it to 'lle' and *then*
tack on the '1', if necessary.
Note [TidyOccEnv]
~~~~~~~~~~~~~~~~~
type TidyOccEnv = UniqFM Int
* Domain = The OccName's FastString. These FastStrings are "taken";
 make sure that we don't re-use
* Int, n = A plausible starting point for new guesses
 There is no guarantee that "FSn" is available;
 you must look that up in the TidyOccEnv. But
 it's a good place to start looking.
* When looking for a renaming for "foo2" we strip off the "2" and start
 with "foo". Otherwise if we tidy twice we get silly names like foo23.
 However, if it started with digits at the end, we always make a name
 with digits at the end, rather than shortening "foo2" to just "foo",
 even if "foo" is unused. Reasons:
 - Plain "foo" might be used later
 - We use trailing digits to subtly indicate a unification variable
 in typechecker error message; see TypeRep.tidyTyVarBndr
We have to take care though! Consider a machine-generated module (#10370)
 module Foo where
 a1 = e1
 a2 = e2
 ...
 a2000 = e2000
Then "a1", "a2" etc are all marked taken. But now if we come across "a7" again,
we have to do a linear search to find a free one, "a2001". That might just be
acceptable once. But if we now come across "a8" again, we don't want to repeat
that search.
So we use the TidyOccEnv mapping for "a" (not "a7" or "a8") as our base for
starting the search; and we make sure to update the starting point for "a"
after we allocate a new one.
Note [Tidying multiple names at once]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Consider
 > :t (id,id,id)
Every id contributes a type variable to the type signature, and all of them are
"a". If we tidy them one by one, we get
 (id,id,id) :: (a2 -> a2, a1 -> a1, a -> a)
which is a bit unfortunate, as it unfairly renames only one of them. What we
would like to see is
 (id,id,id) :: (a3 -> a3, a2 -> a2, a1 -> a1)
To achieve this, the function avoidClashesOccEnv can be used to prepare the
TidyEnv, by “blocking” every name that occurs twice in the map. This way, none
of the "a"s will get the privilege of keeping this name, and all of them will
get a suitable number by tidyOccName.
This prepared TidyEnv can then be used with tidyOccName. See tidyTyCoVarBndrs
for an example where this is used.
This is #12382.
-}typeTidyOccEnv =UniqFM Int-- The in-scope OccNames-- See Note [TidyOccEnv]emptyTidyOccEnv::TidyOccEnv emptyTidyOccEnv =emptyUFM initTidyOccEnv::[OccName ]->TidyOccEnv -- Initialise with names to avoid!initTidyOccEnv =foldl'add emptyUFM whereadd env (OccName _fs )=addToUFM env fs 1-- see Note [Tidying multiple names at once]avoidClashesOccEnv::TidyOccEnv ->[OccName ]->TidyOccEnv avoidClashesOccEnv env occs =go env emptyUFM occs wherego env _[]=env goenv seenOnce ((OccName _fs ):occs )|fs `elemUFM `env =go env seenOnce occs |fs `elemUFM `seenOnce =go (addToUFM env fs 1)seenOnce occs |otherwise=go env (addToUFM seenOnce fs ())occs tidyOccName::TidyOccEnv ->OccName ->(TidyOccEnv ,OccName )tidyOccName env occ @(OccName occ_sp fs )|not(fs `elemUFM `env )=-- Desired OccName is free, so use it,-- and record in 'env' that it's no longer available(addToUFM env fs 1,occ )|otherwise=caselookupUFM env base1 ofNothing->(addToUFM env base1 2,OccName occ_sp base1 )Justn ->find 1n wherebase::String-- Drop trailing digits (see Note [TidyOccEnv])base =dropWhileEndLE isDigit(unpackFS fs )base1 =mkFastString (base ++"1")find !k !n =caselookupUFM env new_fs ofJust{}->find (k +1::Int)(n +k )-- By using n+k, the n argument to find goes-- 1, add 1, add 2, add 3, etc which-- moves at quadratic speed through a dense patchNothing->(new_env ,OccName occ_sp new_fs )wherenew_fs =mkFastString (base ++shown )new_env =addToUFM (addToUFM env new_fs 1)base1 (n +1)-- Update: base1, so that next time we'll start where we left off-- new_fs, so that we know it is taken-- If they are the same (n==1), the former wins-- See Note [TidyOccEnv]{-
************************************************************************
* *
 Binary instance
 Here rather than BinIface because OccName is abstract
* *
************************************************************************
-}instanceBinary NameSpace whereput_ bh VarName =doputByte bh 0put_bh DataName =doputByte bh 1put_bh TvName =doputByte bh 2put_bh TcClsName =doputByte bh 3get bh =doh <-getByte bh caseh of0->doreturnVarName 1->doreturnDataName 2->doreturnTvName _->doreturnTcClsName instanceBinary OccName whereput_ bh (OccName aa ab )=doput_ bh aa put_ bh ab get bh =doaa <-get bh ab <-get bh return(OccName aa ab )