[project @ 1998-12-02 13:17:09 by simonm]

[ghc-hetmet.git] / ghc / lib / std / Prelude.lhs

diff --git a/ghc/lib/std/Prelude.lhs b/ghc/lib/std/Prelude.lhs
index 1ba96bb..bf7cbd1 100644 (file)
--- a/ghc/lib/std/Prelude.lhs
+++ b/ghc/lib/std/Prelude.lhs
@@ -68,58 +68,23 @@ import PrelBase
 import PrelList
 import PrelRead
 import PrelNum
+import PrelNumExtra
 import PrelTup
 import PrelMaybe
 import PrelEither
 import PrelBounded
+import PrelConc
 import Monad
 import Maybe
-import PrelErr   ( error, seqError )
-import IO  ( IO, FilePath, IOError,
-            fail, userError, catch,
-            putChar, putStr, putStrLn, print,
-            getChar, getLine, getContents, interact,
-            readFile, writeFile, appendFile, readIO, readLn
-          )
-
-{- Declared elsewhere:
-PrelBase: infixr 9 .
-PrelNum:  infixr 8 ^, ^^, **
-PrelBase: infixl *
-PrelNum:  infixl 7 /, %, `quot`, `rem`, `div`, `mod`
-PrelBase: infixl 6 +, -
-PrelBase: infixr 5 :, ++
-PrelBase: infix  4 ==, /=, <. <=, >=, >
-PrelBase: infixr 3 &&
-PrelBase: infixr 2 ||
-PrelBase: infixl >>, >>=
-PrelBase: infixr $
--}
-infixr 0 `seq`
-
+import PrelErr   ( error )
+import IO
 
 -- These can't conveniently be defined in PrelBase because they use numbers,
 -- or I/O, so here's a convenient place to do them.
 
-strict      :: Eval a => (a -> b) -> a -> b
+strict      :: (a -> b) -> a -> b
 strict f x  = x `seq` f x
 
-
--- "seq" is defined a bit wierdly (see below)
---
--- The reason for the strange "0# -> parError" case is that
--- it fools the compiler into thinking that seq is non-strict in
--- its second argument (even if it inlines seq at the call site).
--- If it thinks seq is strict in "y", then it often evaluates
--- "y" before "x", which is totally wrong.  
---
--- Just before converting from Core to STG there's a bit of magic
--- that recognises the seq# and eliminates the duff case.
-
-{-# INLINE seq  #-}
-seq :: Eval a => a -> b -> b
-seq  x y = case (seq#  x) of { 0# -> seqError; _ -> y }
-
 -- It is expected that compilers will recognize this and insert error
 -- messages which are more appropriate to the context in which undefined 
 -- appears.