X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=GHC%2FErr.lhs;h=90142f400ff76b775eb2f5550cf26380adbda4c9;hb=7a97ec4b12e1fbec5505f82032cf4dc435b5a60c;hp=d3596ff80f25c041141b55c335e6bd20e7257902;hpb=e1550f94be21fa41bbc7bd13e19220d213133d9f;p=ghc-base.git diff --git a/GHC/Err.lhs b/GHC/Err.lhs index d3596ff..90142f4 100644 --- a/GHC/Err.lhs +++ b/GHC/Err.lhs @@ -1,61 +1,58 @@ -% ----------------------------------------------------------------------------- -% $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 @@ -63,71 +60,31 @@ undefined = error "Prelude.undefined" \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}