[project @ 1997-11-13 17:08:31 by simonm]

[ghc-hetmet.git] / ghc / lib / ghc / GHCmain.lhs

diff --git a/ghc/lib/ghc/GHCmain.lhs b/ghc/lib/ghc/GHCmain.lhs
index 3926ba9..0a67a1d 100644 (file)
--- a/ghc/lib/ghc/GHCmain.lhs
+++ b/ghc/lib/ghc/GHCmain.lhs
@@ -1,33 +1,19 @@
-\section[GHCmain]{Module @GHCmain@}
+%
+% (c) The AQUA Project, Glasgow University, 1994-1997
+%
 
-This is the mainPrimIO that must be used for Haskell~1.3.
+\section[GHCmain]{Module @GHCmain@}
 
 \begin{code}
-module GHCmain( mainPrimIO ) where
+module GHCmain( mainIO ) where
 
 import Prelude
-import qualified Main  -- for type of "Main.main"
-import IOBase
-import STBase
+import {-# SOURCE #-} qualified Main   -- for type of "Main.main"
 \end{code}
 
 \begin{code}
-mainPrimIO = ST $ \ s ->
-    case Main.main   of { IO (ST main_guts) ->
-    case main_guts s of { (result, s2@(S# _)) ->
-    case result   of
-      Right ()  -> ( (), s2 )
-      Left  err -> error ("I/O error: "++showsPrec 0 err "\n")
-    }}
+mainIO :: IO ()                -- It must be of type (IO t) because that's what
+                       -- the RTS expects.  GHC doesn't check this, so
+                       -- make sure this type signature stays!
+mainIO = catch Main.main (\err -> error ("I/O error: "++showsPrec 0 err "\n"))
 \end{code}
-
-OLD COMMENT:
-
-Nota Bene!  @mainIO@ is written as an explicit function, rather than
-by saying: @mainIO = requestToIO main@ so that the code generator
-recognises @mainIO@ as a {\em function} (hence HNF, hence not
-updatable), rather than a zero-arity CAF (hence updatable).  If it is
-updated, then we have a mega-space leak, because the entire action
-(@requestToIO main@) is retained indefinitely.
-
-(This doesn't waste work because @mainIO@ is only used once.)