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+%
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
+%
+\section[PrelInfo]{The @PrelInfo@ interface to the compiler's prelude knowledge}
+
+\begin{code}
+module PrelInfo (
+	module MkId,
+
+	ghcPrimExports,
+	wiredInThings, basicKnownKeyNames,
+	primOpId,
+	
+	-- Random other things
+	maybeCharLikeCon, maybeIntLikeCon,
+
+	-- Class categories
+	isNumericClass, isStandardClass
+
+    ) where
+
+#include "HsVersions.h"
+
+import PrelNames	( basicKnownKeyNames, 
+			  hasKey, charDataConKey, intDataConKey,
+			  numericClassKeys, standardClassKeys )
+
+import PrimOp		( PrimOp, allThePrimOps, primOpOcc, primOpTag, maxPrimOpTag )
+import DataCon		( DataCon )
+import Id		( Id, idName )
+import MkId		( mkPrimOpId, wiredInIds )
+import MkId		-- All of it, for re-export
+import Name		( nameOccName )
+import TysPrim		( primTyCons )
+import TysWiredIn	( wiredInTyCons )
+import HscTypes 	( TyThing(..), implicitTyThings, GenAvailInfo(..), RdrAvailInfo )
+import Class	 	( Class, classKey )
+import Type		( funTyCon )
+import TyCon		( tyConName )
+import Util		( isIn )
+
+import Array		( Array, array, (!) )
+\end{code}
+
+%************************************************************************
+%*									*
+\subsection[builtinNameInfo]{Lookup built-in names}
+%*									*
+%************************************************************************
+
+We have two ``builtin name funs,'' one to look up @TyCons@ and
+@Classes@, the other to look up values.
+
+\begin{code}
+wiredInThings :: [TyThing]
+wiredInThings		
+  = concat
+    [		-- Wired in TyCons and their implicit Ids
+	  tycon_things
+	, concatMap implicitTyThings tycon_things
+
+		-- Wired in Ids
+	, map AnId wiredInIds
+
+		-- PrimOps
+	, map (AnId . mkPrimOpId) allThePrimOps
+    ]
+  where
+    tycon_things = map ATyCon ([funTyCon] ++ primTyCons ++ wiredInTyCons)
+\end{code}
+
+We let a lot of "non-standard" values be visible, so that we can make
+sense of them in interface pragmas. It's cool, though they all have
+"non-standard" names, so they won't get past the parser in user code.
+
+%************************************************************************
+%*									*
+		PrimOpIds
+%*									*
+%************************************************************************
+
+\begin{code}
+primOpIds :: Array Int Id	-- Indexed by PrimOp tag
+primOpIds = array (1,maxPrimOpTag) [ (primOpTag op, mkPrimOpId op) 
+				   | op <- allThePrimOps]
+
+primOpId :: PrimOp -> Id
+primOpId op = primOpIds ! primOpTag op
+\end{code}
+
+
+%************************************************************************
+%*									*
+\subsection{Export lists for pseudo-modules (GHC.Prim)}
+%*									*
+%************************************************************************
+
+GHC.Prim "exports" all the primops and primitive types, some 
+wired-in Ids.
+
+\begin{code}
+ghcPrimExports :: [RdrAvailInfo]
+ghcPrimExports
+ = map (Avail . nameOccName . idName) ghcPrimIds ++
+   map (Avail . primOpOcc) allThePrimOps ++
+   [ AvailTC occ [occ] |
+     n <- funTyCon : primTyCons, let occ = nameOccName (tyConName n) 
+   ]
+\end{code}
+
+
+%************************************************************************
+%*									*
+\subsection{Built-in keys}
+%*									*
+%************************************************************************
+
+ToDo: make it do the ``like'' part properly (as in 0.26 and before).
+
+\begin{code}
+maybeCharLikeCon, maybeIntLikeCon :: DataCon -> Bool
+maybeCharLikeCon con = con `hasKey` charDataConKey
+maybeIntLikeCon  con = con `hasKey` intDataConKey
+\end{code}
+
+
+%************************************************************************
+%*									*
+\subsection{Class predicates}
+%*									*
+%************************************************************************
+
+\begin{code}
+isNumericClass, isStandardClass :: Class -> Bool
+
+isNumericClass     clas = classKey clas `is_elem` numericClassKeys
+isStandardClass    clas = classKey clas `is_elem` standardClassKeys
+is_elem = isIn "is_X_Class"
+\end{code}