[project @ 2003-07-23 13:08:22 by simonpj]

[ghc-hetmet.git] / ghc / compiler / coreSyn / CoreSyn.lhs

diff --git a/ghc/compiler/coreSyn/CoreSyn.lhs b/ghc/compiler/coreSyn/CoreSyn.lhs
index 12f750f..4c70bb3 100644 (file)
--- a/ghc/compiler/coreSyn/CoreSyn.lhs
+++ b/ghc/compiler/coreSyn/CoreSyn.lhs
@@ -79,7 +79,8 @@ data Expr b   -- "b" for the type of binders,
   | Lam   b (Expr b)
   | Let   (Bind b) (Expr b)
   | Case  (Expr b) b [Alt b]   -- Binder gets bound to value of scrutinee
-                               -- DEFAULT case must be *first*, if it occurs at all
+       -- Invariant: the list of alternatives is ALWAYS EXHAUSTIVE
+       -- Invariant: the DEFAULT case must be *first*, if it occurs at all
   | Note  Note (Expr b)
   | Type  Type                 -- This should only show up at the top
                                -- level of an Arg
@@ -109,6 +110,8 @@ data Note
   | InlineMe           -- Instructs simplifer to treat the enclosed expression
                        -- as very small, and inline it at its call sites
 
+  | CoreNote String     -- A generic core annotation, propagated but not used by GHC
+
 -- NOTE: we also treat expressions wrapped in InlineMe as
 -- 'cheap' and 'dupable' (in the sense of exprIsCheap, exprIsDupable)
 -- What this means is that we obediently inline even things that don't
@@ -549,6 +552,7 @@ seqExprs [] = ()
 seqExprs (e:es) = seqExpr e `seq` seqExprs es
 
 seqNote (Coerce t1 t2) = seqType t1 `seq` seqType t2
+seqNote (CoreNote s)   = s `seq` ()
 seqNote other         = ()
 
 seqBndr b = b `seq` ()