-% -----------------------------------------------------------------------------
-% $Id: Err.lhs,v 1.2 2001/07/31 13:11:07 simonmar Exp $
-%
-% (c) The University of Glasgow, 1994-2000
-%
-
-\section[GHC.Err]{Module @GHC.Err@}
-
-The GHC.Err module defines the code for the wired-in error functions,
-which have a special type in the compiler (with "open tyvars").
-
-We cannot define these functions in a module where they might be used
-(e.g., GHC.Base), because the magical wired-in type will get confused
-with what the typechecker figures out.
-
\begin{code}
-{-# OPTIONS -fno-implicit-prelude #-}
-module GHC.Err
+{-# LANGUAGE CPP, NoImplicitPrelude #-}
+{-# OPTIONS_HADDOCK hide #-}
+
+-----------------------------------------------------------------------------
+-- |
+-- Module : GHC.Err
+-- Copyright : (c) The University of Glasgow, 1994-2002
+-- License : see libraries/base/LICENSE
+--
+-- Maintainer : cvs-ghc@haskell.org
+-- Stability : internal
+-- Portability : non-portable (GHC extensions)
+--
+-- The "GHC.Err" module defines the code for the wired-in error functions,
+-- which have a special type in the compiler (with \"open tyvars\").
+--
+-- We cannot define these functions in a module where they might be used
+-- (e.g., "GHC.Base"), because the magical wired-in type will get confused
+-- with what the typechecker figures out.
+--
+-----------------------------------------------------------------------------
+
+-- #hide
+module GHC.Err
(
- irrefutPatError
- , noMethodBindingError
- , nonExhaustiveGuardsError
- , patError
- , recSelError
- , recConError
- , recUpdError -- :: String -> a
-
- , absentErr, parError -- :: a
- , seqError -- :: a
-
- , errorCString -- :: Addr# -> a -- Arg is a ptr to C string
- , error -- :: String -> a
- , assertError -- :: String -> Bool -> a -> a
-
- , undefined -- :: a
+ absentErr -- :: a
+ , divZeroError -- :: a
+ , overflowError -- :: a
+
+ , error -- :: String -> a
+
+ , undefined -- :: a
) where
-import GHC.Base
-import GHC.List ( span )
+#ifndef __HADDOCK__
+import GHC.Types
import GHC.Exception
+#endif
\end{code}
%*********************************************************
-%* *
+%* *
\subsection{Error-ish functions}
-%* *
+%* *
%*********************************************************
\begin{code}
--- error stops execution and displays an error message
-error :: String -> a
+-- | 'error' stops execution and displays an error message.
+error :: [Char] -> a
error s = throw (ErrorCall s)
-errorCString :: Addr# -> a
-errorCString s = error (unpackCString s)
-
+-- | A special case of 'error'.
-- It is expected that compilers will recognize this and insert error
--- messages which are more appropriate to the context in which undefined
+-- messages which are more appropriate to the context in which 'undefined'
-- appears.
undefined :: a
\end{code}
%*********************************************************
-%* *
+%* *
\subsection{Compiler generated errors + local utils}
-%* *
+%* *
%*********************************************************
Used for compiler-generated error message;
encoding saves bytes of string junk.
\begin{code}
-absentErr, parError, seqError :: a
+absentErr :: a
absentErr = error "Oops! The program has entered an `absent' argument!\n"
-parError = error "Oops! Entered GHCerr.parError (a GHC bug -- please report it!)\n"
-seqError = error "Oops! Entered seqError (a GHC bug -- please report it!)\n"
-
\end{code}
+Divide by zero and arithmetic overflow.
+We put them here because they are needed relatively early
+in the libraries before the Exception type has been defined yet.
+
\begin{code}
-irrefutPatError
- , noMethodBindingError
- , nonExhaustiveGuardsError
- , patError
- , recSelError
- , recConError
- , recUpdError :: String -> a
-
-noMethodBindingError s = throw (NoMethodError (untangle s "No instance nor default method for class operation"))
-irrefutPatError s = throw (PatternMatchFail (untangle s "Irrefutable pattern failed for pattern"))
-nonExhaustiveGuardsError s = throw (PatternMatchFail (untangle s "Non-exhaustive guards in"))
-patError s = throw (PatternMatchFail (untangle s "Non-exhaustive patterns in"))
-recSelError s = throw (RecSelError (untangle s "Missing field in record selection"))
-recConError s = throw (RecConError (untangle s "Missing field in record construction"))
-recUpdError s = throw (RecUpdError (untangle s "Record doesn't contain field(s) to be updated"))
-
-
-assertError :: String -> Bool -> a -> a
-assertError str pred v
- | pred = v
- | otherwise = throw (AssertionFailed (untangle str "Assertion failed"))
+{-# NOINLINE divZeroError #-}
+divZeroError :: a
+divZeroError = throw DivideByZero
+{-# NOINLINE overflowError #-}
+overflowError :: a
+overflowError = throw Overflow
\end{code}
-
-(untangle coded message) expects "coded" to be of the form
-
- "location|details"
-
-It prints
-
- location message details
-
-\begin{code}
-untangle :: String -> String -> String
-untangle coded message
- = location
- ++ ": "
- ++ message
- ++ details
- ++ "\n"
- where
- (location, details)
- = case (span not_bar coded) of { (loc, rest) ->
- case rest of
- ('|':det) -> (loc, ' ' : det)
- _ -> (loc, "")
- }
- not_bar c = c /= '|'
-\end{code}
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