[project @ 2001-02-20 09:40:43 by simonpj]

[ghc-hetmet.git] / ghc / compiler / prelude / PrelNames.lhs

diff --git a/ghc/compiler/prelude/PrelNames.lhs b/ghc/compiler/prelude/PrelNames.lhs
index 91530c6..cf2e96d 100644 (file)
--- a/ghc/compiler/prelude/PrelNames.lhs
+++ b/ghc/compiler/prelude/PrelNames.lhs
@@ -22,6 +22,8 @@ module PrelNames (
        knownKeyNames, 
         mkTupNameStr, mkTupConRdrName,
 
+       SyntaxMap, vanillaSyntaxMap, SyntaxList, syntaxList, 
+
        ------------------------------------------------------------
        -- Goups of classes and types
        needsDataDeclCtxtClassKeys, cCallishClassKeys, noDictClassKeys,
@@ -109,6 +111,7 @@ knownKeyNames
        -- ClassOps 
        fromIntName,
        fromIntegerName,
+       negateName,
        geName,
        minusName,
        enumFromName,
@@ -376,6 +379,7 @@ numClassName          = clsQual pREL_NUM_Name SLIT("Num") numClassKey
 fromIntName      = varQual pREL_NUM_Name SLIT("fromInt") fromIntClassOpKey
 fromIntegerName   = varQual pREL_NUM_Name SLIT("fromInteger") fromIntegerClassOpKey
 minusName        = varQual pREL_NUM_Name SLIT("-") minusClassOpKey
+negateName       = varQual pREL_NUM_Name SLIT("negate") negateClassOpKey
 plusIntegerName   = varQual pREL_NUM_Name SLIT("plusInteger") plusIntegerIdKey
 timesIntegerName  = varQual pREL_NUM_Name SLIT("timesInteger") timesIntegerIdKey
 integerTyConName  = tcQual  pREL_NUM_Name SLIT("Integer") integerTyConKey
@@ -814,6 +818,7 @@ enumFromToClassOpKey              = mkPreludeMiscIdUnique 107
 enumFromThenToClassOpKey      = mkPreludeMiscIdUnique 108
 eqClassOpKey                 = mkPreludeMiscIdUnique 109
 geClassOpKey                 = mkPreludeMiscIdUnique 110
+negateClassOpKey             = mkPreludeMiscIdUnique 111
 failMClassOpKey                      = mkPreludeMiscIdUnique 112
 thenMClassOpKey                      = mkPreludeMiscIdUnique 113 -- (>>=)
        -- Just a place holder for  unbound variables  produced by the renamer:
@@ -873,6 +878,49 @@ cCallishTyKeys =
 
 %************************************************************************
 %*                                                                     *
+\subsection{Re-bindable desugaring names}
+%*                                                                     *
+%************************************************************************
+
+Haskell 98 says that when you say "3" you get the "fromInt" from the
+Standard Prelude, regardless of what is in scope.   However, to experiment
+with having a language that is less coupled to the standard prelude, we're
+trying a non-standard extension that instead gives you whatever "Prelude.fromInt"
+happens to be in scope.  Then you can
+       import Prelude ()
+       import MyPrelude as Prelude
+to get the desired effect.
+
+The SyntaxNames record gives all the names you can rebind in this way.
+This record of names needs to go through the renamer to map RdrNames to
+Names (i.e. look up the names in the in-scope environment), to suck in
+their type signatures from interface file(s).
+
+\begin{code}
+type SyntaxList = [(Name, RdrName)]
+  -- Maps a Name, which identifies the standard built-in thing
+  -- to a RdrName for the re-mapped version of the built-in thing
+
+syntaxList :: SyntaxList
+syntaxList =[ (fromIntName,            mkUnqual varName SLIT("fromInt"))
+            , (fromIntegerName,        mkUnqual varName SLIT("fromInteger"))
+            ,  (fromRationalName,      mkUnqual varName SLIT("fromRational"))
+            ,  (negateName,            mkUnqual varName SLIT("negate"))
+            ,  (minusName,             mkUnqual varName SLIT("-"))
+                       -- For now that's all.  We may add booleans and lists later.
+           ]
+
+
+type SyntaxMap = Name -> Name
+  -- Maps a standard built-in name, such as PrelNum.fromInt
+  -- to its re-mapped version, such as MyPrelude.fromInt
+
+vanillaSyntaxMap name = name
+\end{code}
+
+
+%************************************************************************
+%*                                                                     *
 \subsection[Class-std-groups]{Standard groups of Prelude classes}
 %*                                                                     *
 %************************************************************************