-- 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
+-- the \"namespace\" that the name came from, e.g. the namespace of value, type constructors or
-- data constructors
--
-- * 'RdrName.RdrName': see "RdrName#name_types"
mkSuperDictSelOcc, mkLocalOcc, mkMethodOcc, mkInstTyTcOcc,
mkInstTyCoOcc, mkEqPredCoOcc,
mkVectOcc, mkVectTyConOcc, mkVectDataConOcc, mkVectIsoOcc,
- mkPArrayTyConOcc, mkPArrayDataConOcc,
+ mkPDataTyConOcc, mkPDataDataConOcc,
mkPReprTyConOcc,
mkPADFunOcc,
occNameFS, occNameString, occNameSpace,
isVarOcc, isTvOcc, isTcOcc, isDataOcc, isDataSymOcc, isSymOcc, isValOcc,
- parenSymOcc, reportIfUnused,
+ parenSymOcc, startsWithUnderscore,
isTcClsNameSpace, isTvNameSpace, isDataConNameSpace, isVarNameSpace, isValNameSpace,
import Util
import Unique
import BasicTypes
-import StaticFlags
import UniqFM
import UniqSet
import FastString
-import FastTypes
import Outputable
import Binary
-
-import GHC.Exts
import Data.Char
\end{code}
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, so we can make a Unique using
+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 reprsenting the name space. This in turn makes it
easy to build an OccEnv.
\begin{code}
instance Uniquable OccName where
- getUnique (OccName ns fs)
- = mkUnique char (iBox (uniqueOfFS fs))
- where -- See notes above about this getUnique function
- char = case ns of
- VarName -> 'i'
- DataName -> 'd'
- TvName -> 'v'
- TcClsName -> 't'
+ -- 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
newtype OccEnv a = A (UniqFM a)
\begin{code}
-reportIfUnused :: OccName -> Bool
--- ^ Haskell 98 encourages compilers to suppress warnings about
--- unused names in a pattern if they start with @_@: this implements
--- that test
-reportIfUnused occ = case occNameString occ of
- ('_' : _) -> False
- _other -> True
+startsWithUnderscore :: OccName -> Bool
+-- ^ Haskell 98 encourages compilers to suppress warnings about unsed
+-- names in a pattern if they start with @_@: this implements that test
+startsWithUnderscore occ = case occNameString occ of
+ ('_' : _) -> True
+ _other -> False
\end{code}
Here's our convention for splitting up the interface file name space:
- d... dictionary identifiers
- (local variables, so no name-clash worries)
+ d... dictionary identifiers
+ (local variables, so no name-clash worries)
- \$f... dict-fun identifiers (from inst decls)
- \$dm... default methods
- \$p... superclass selectors
- \$w... workers
- :T... compiler-generated tycons for dictionaries
- :D... ...ditto data cons
- :Co... ...ditto coercions
- \$sf.. specialised version of f
+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
- in encoded form these appear as Zdfxxx etc
+ $f... Dict-fun identifiers (from inst decls)
+ $dmop Default method for 'op'
+ $pnC n'th superclass selector for class C
+ $wf Worker for functtoin 'f'
+ $sf.. Specialised version of f
+ T:C Tycon for dictionary for class C
+ D:C Data constructor for dictionary for class C
+ NTCo:T Coercion connecting newtype T with its representation type
+ TFCo:R Coercion connecting a data family to its respresentation type R
+
+In encoded form these appear as Zdfxxx etc
:... keywords (export:, letrec: etc.)
--- I THINK THIS IS WRONG!
mkInstTyCoOcc, mkEqPredCoOcc,
mkCon2TagOcc, mkTag2ConOcc, mkMaxTagOcc,
mkVectOcc, mkVectTyConOcc, mkVectDataConOcc, mkVectIsoOcc,
- mkPArrayTyConOcc, mkPArrayDataConOcc, mkPReprTyConOcc, mkPADFunOcc
+ mkPDataTyConOcc, mkPDataDataConOcc, mkPReprTyConOcc, mkPADFunOcc
:: OccName -> OccName
-- These derived variables have a prefix that no Haskell value could have
mkWorkerOcc = mk_simple_deriv varName "$w"
mkDefaultMethodOcc = mk_simple_deriv varName "$dm"
mkDerivedTyConOcc = mk_simple_deriv tcName ":" -- The : prefix makes sure it classifies
-mkClassTyConOcc = mk_simple_deriv tcName ":T" -- as a tycon/datacon
-mkClassDataConOcc = mk_simple_deriv dataName ":D" -- We go straight to the "real" data con
+mkClassTyConOcc = mk_simple_deriv tcName "T:" -- as a tycon/datacon
+mkClassDataConOcc = mk_simple_deriv dataName "D:" -- We go straight to the "real" data con
-- for datacons from classes
mkDictOcc = mk_simple_deriv varName "$d"
mkIPOcc = mk_simple_deriv varName "$i"
mkSpecOcc = mk_simple_deriv varName "$s"
mkForeignExportOcc = mk_simple_deriv varName "$f"
-mkNewTyCoOcc = mk_simple_deriv tcName ":Co"
-mkInstTyCoOcc = mk_simple_deriv tcName ":CoF" -- derived from rep ty
+mkNewTyCoOcc = mk_simple_deriv tcName "NTCo:" -- Coercion for newtypes
+mkInstTyCoOcc = mk_simple_deriv tcName "TFCo:" -- Coercion for type functions
mkEqPredCoOcc = mk_simple_deriv tcName "$co"
-- used in derived instances
mkVectTyConOcc = mk_simple_deriv tcName ":V_"
mkVectDataConOcc = mk_simple_deriv dataName ":VD_"
mkVectIsoOcc = mk_simple_deriv varName "$VI_"
-mkPArrayTyConOcc = mk_simple_deriv tcName ":VP_"
-mkPArrayDataConOcc = mk_simple_deriv dataName ":VPD_"
+mkPDataTyConOcc = mk_simple_deriv tcName ":VP_"
+mkPDataDataConOcc = mk_simple_deriv dataName ":VPD_"
mkPReprTyConOcc = mk_simple_deriv tcName ":VR_"
mkPADFunOcc = mk_simple_deriv varName "$PA_"
\begin{code}
-- | Derive a name for the representation type constructor of a
-- @data@\/@newtype@ instance.
-mkInstTyTcOcc :: Int -- ^ DFun Index
- -> OccName -- ^ Family name, e.g. @Map@
- -> OccName -- ^ Nice unique version, e.g. @:R23Map@
-mkInstTyTcOcc index occ
- = mk_deriv tcName (":R" ++ show index) (occNameString occ)
+mkInstTyTcOcc :: String -- ^ Family name, e.g. @Map@
+ -> OccSet -- ^ avoid these Occs
+ -> OccName -- ^ @R:Map@
+mkInstTyTcOcc str set =
+ chooseUniqueOcc tcName ('R' : ':' : str) set
\end{code}
\begin{code}
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?
- -> Int -- ^ Unique index
+ -> OccSet -- ^ avoid these Occs
-> OccName -- ^ E.g. @$f3OrdMaybe@
-- In hs-boot files we make dict funs like $fx7ClsTy, which get bound to the real
-- thing when we compile the mother module. Reason: we don't know exactly
-- what the mother module will call it.
-mkDFunOcc info_str is_boot index
- = mk_deriv VarName prefix string
+mkDFunOcc info_str is_boot set
+ = chooseUniqueOcc VarName (prefix ++ info_str) set
where
prefix | is_boot = "$fx"
| otherwise = "$f"
- string | opt_PprStyle_Debug = show index ++ info_str
- | otherwise = show index
+\end{code}
+
+Sometimes we need to pick an OccName that has not already been used,
+given a set of in-use OccNames.
+
+\begin{code}
+chooseUniqueOcc :: NameSpace -> String -> OccSet -> OccName
+chooseUniqueOcc ns str set = loop (mkOccName ns str) (0::Int)
+ where
+ loop occ n
+ | occ `elemOccSet` set = loop (mkOccName ns (str ++ show n)) (n+1)
+ | otherwise = occ
\end{code}
We used to add a '$m' to indicate a method, but that gives rise to bad
projects / ghc-hetmet.git / blobdiff