X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Fprelude%2FPrelInfo.lhs;h=dbeb6de00be4e6e0aa93edb108b32f289a85f1b4;hb=eb5ba64de7cbef6c541d87e3afb644c1115ce103;hp=31457b2b630e113fd28ab1b40f7480a777eadfa6;hpb=0065d5ab628975892cea1ec7303f968c3338cbe1;p=ghc-hetmet.git

diff --git a/compiler/prelude/PrelInfo.lhs b/compiler/prelude/PrelInfo.lhs
index 31457b2..dbeb6de 100644
--- a/compiler/prelude/PrelInfo.lhs
+++ b/compiler/prelude/PrelInfo.lhs
@@ -28,7 +28,6 @@ import PrelNames	( basicKnownKeyNames,
 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 )
@@ -39,7 +38,7 @@ import Type		( funTyCon )
 import TyCon		( tyConName )
 import Util		( isIn )
 
-import Array		( Array, array, (!) )
+import Data.Array
 \end{code}
 
 %************************************************************************
@@ -48,11 +47,30 @@ import Array		( Array, array, (!) )
 %*									*
 %************************************************************************
 
-We have two ``builtin name funs,'' one to look up @TyCons@ and
-@Classes@, the other to look up values.
+Notes about wired in things
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+* Wired-in things are Ids\/TyCons that are completely known to the compiler.
+  They are global values in GHC, (e.g.  listTyCon :: TyCon).
+
+* A wired in Name contains the thing itself inside the Name: 
+	see Name.wiredInNameTyThing_maybe
+  (E.g. listTyConName contains listTyCon. 
+
+* The name cache is initialised with (the names of) all wired-in things
+
+* The type checker sees if the Name is wired in before looking up 
+  the name in the type environment.  So the type envt itself contains
+  no wired in things.
+
+* MkIface prunes out wired-in things before putting them in an interface file.
+  So interface files never contain wired-in things.
+
 
 \begin{code}
 wiredInThings :: [TyThing]
+-- This list is used only to initialise HscMain.knownKeyNames
+-- to ensure that when you say "Prelude.map" in your source code, you
+-- get a Name with the correct known key
 wiredInThings		
   = concat
     [		-- Wired in TyCons and their implicit Ids
@@ -135,5 +153,7 @@ isNumericClass, isStandardClass :: Class -> Bool
 
 isNumericClass     clas = classKey clas `is_elem` numericClassKeys
 isStandardClass    clas = classKey clas `is_elem` standardClassKeys
+
+is_elem :: Eq a => a -> [a] -> Bool
 is_elem = isIn "is_X_Class"
 \end{code}