[project @ 2002-01-23 11:11:13 by simonmar]

Revert to running command-line statements in the context of the
current thread, so that ^C exceptions get delivered to the right
place.

Now that a deadlock generates an exception this is not so bad, but it
would be nice to do it the "right" way so I've left the old code in a
comment for now.

diff --git a/ghc/compiler/compMan/CompManager.lhs b/ghc/compiler/compMan/CompManager.lhs
index b79d4de..7eb2c91 100644 (file)
--- a/ghc/compiler/compMan/CompManager.lhs
+++ b/ghc/compiler/compMan/CompManager.lhs
@@ -309,10 +309,22 @@ cmRunStmt cmstate@CmState{ hst=hst, hit=hit, pcs=pcs, pls=pls, ic=icontext }
                             return (cmstate{ pcs=new_pcs, pls=new_pls, ic=new_ic }, 
                                     CmRunOk names)
 
--- We run the statement in a "sandbox", which amounts to calling into
--- the RTS to request a new main thread.  The main benefit is that
--- there's no danger that exceptions raised by the expression can
--- affect the interpreter.
+
+-- We run the statement in a "sandbox" to protect the rest of the
+-- system from anything the expression might do.  For now, this
+-- consists of just wrapping it in an exception handler, but see below
+-- for another version.
+
+sandboxIO :: IO a -> IO (Either Int (Either Exception a))
+sandboxIO thing = do
+  r <- Exception.try thing
+  return (Right r)
+
+{-
+-- This version of sandboxIO runs the expression in a completely new
+-- RTS main thread.  It is disabled for now because ^C exceptions
+-- won't be delivered to the new thread, instead they'll be delivered
+-- to the (blocked) GHCi main thread.
 
 sandboxIO :: IO a -> IO (Either Int (Either Exception a))
 sandboxIO thing = do
@@ -331,6 +343,7 @@ sandboxIO thing = do
 foreign import "rts_evalStableIO"  {- safe -}
   rts_evalStableIO :: StablePtr (IO a) -> Ptr (StablePtr a) -> IO CInt
   -- more informative than the C type!
+-}
 #endif
 
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