-% -----------------------------------------------------------------------------
-% $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 #-}
+{-# OPTIONS_GHC -fno-implicit-prelude #-}
+-----------------------------------------------------------------------------
+-- |
+-- 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
, patError
, recSelError
, recConError
- , recUpdError -- :: String -> a
+ , runtimeError -- :: Addr# -> a -- Addr# points to UTF8 encoded C string
- , absentErr, parError -- :: a
- , seqError -- :: a
+ , absentErr -- :: a
+ , divZeroError -- :: a
- , errorCString -- :: Addr# -> a -- Arg is a ptr to C string
, error -- :: String -> a
, assertError -- :: String -> Bool -> a -> a
, undefined -- :: a
) where
+#ifndef __HADDOCK__
import GHC.Base
import GHC.List ( span )
import GHC.Exception
+#endif
\end{code}
%*********************************************************
%*********************************************************
\begin{code}
--- error stops execution and displays an error message
+-- | 'error' stops execution and displays an error message.
error :: String -> 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
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}
\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"))
+recSelError, recConError, irrefutPatError, runtimeError,
+ nonExhaustiveGuardsError, patError, noMethodBindingError
+ :: Addr# -> a -- All take a UTF8-encoded C string
+
+recSelError s = throw (RecSelError (unpackCStringUtf8# s)) -- No location info unfortunately
+runtimeError s = error (unpackCStringUtf8# s) -- No location info unfortunately
+
nonExhaustiveGuardsError s = throw (PatternMatchFail (untangle s "Non-exhaustive guards in"))
+irrefutPatError s = throw (PatternMatchFail (untangle s "Irrefutable pattern failed for pattern"))
+recConError s = throw (RecConError (untangle s "Missing field in record construction"))
+noMethodBindingError s = throw (NoMethodError (untangle s "No instance nor default method for class operation"))
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 :: Addr# -> Bool -> a -> a
assertError str pred v
| pred = v
| otherwise = throw (AssertionFailed (untangle str "Assertion failed"))
-
\end{code}
location message details
\begin{code}
-untangle :: String -> String -> String
+untangle :: Addr# -> String -> String
untangle coded message
= location
++ ": "
++ details
++ "\n"
where
+ coded_str = unpackCStringUtf8# coded
+
(location, details)
- = case (span not_bar coded) of { (loc, rest) ->
+ = case (span not_bar coded_str) of { (loc, rest) ->
case rest of
('|':det) -> (loc, ' ' : det)
_ -> (loc, "")
}
not_bar c = c /= '|'
\end{code}
+
+Divide by zero. We put it here because it is needed relatively early
+in the libraries before the Exception type has been defined yet.
+
+\begin{code}
+{-# NOINLINE divZeroError #-}
+divZeroError :: a
+divZeroError = throw (ArithException DivideByZero)
+\end{code}
+
projects / ghc-base.git / blobdiff