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|
-- Compiler Toolkit: basic error management
--
-- Author : Manuel M. T. Chakravarty
-- Created: 20 February 95
--
-- Version $Revision: 1.16 $ from $Date: 1999/09/22 09:36:31 $
--
-- Copyright (c) [1995..1999] Manuel M. T. Chakravarty
--
-- This library is free software; you can redistribute it and/or
-- modify it under the terms of the GNU Library General Public
-- License as published by the Free Software Foundation; either
-- version 2 of the License, or (at your option) any later version.
--
-- This library is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-- Library General Public License for more details.
--
--- DESCRIPTION ---------------------------------------------------------------
--
-- This modules exports some auxilliary routines for error handling.
--
--- DOCU ----------------------------------------------------------------------
--
-- language: Haskell 98
--
-- * the single lines of error messages shouldn't be to long as file name
-- and position are prepended at each line
--
--- TODO ----------------------------------------------------------------------
--
-- * `errorAtPos' should be removed when we can handle multiple error messages
-- in the lexer and parser.
--
module Errors (-- handling of internal error
--
interr, todo,
--
-- errors in the compiled program
--
ErrorLvl(..), Error, makeError, errorLvl, showError, errorAtPos)
where
import Config (assertEnabled)
import Common (Position)
import Utils (indentMultilineString)
-- internal errors
-- ---------------
-- raise a fatal internal error; message may have multiple lines (EXPORTED)
--
interr :: String -> a
interr msg = error ("INTERNAL COMPILER ERROR:\n"
++ indentMultilineString 2 msg
++ "\n")
-- raise a error due to a implementation restriction; message may have multiple
-- lines (EXPORTED)
--
todo :: String -> a
todo msg = error ("Feature not yet implemented:\n"
++ indentMultilineString 2 msg
++ "\n")
-- errors in the compiled program
-- ------------------------------
-- the higher the level of an error, the more critical it is (EXPORTED)
--
data ErrorLvl = WarningErr -- does not affect compilation
| ErrorErr -- cannot generate code
| FatalErr -- abort immediately
deriving (Eq, Ord)
data Error = Error ErrorLvl Position [String] -- (EXPORTED ABSTRACTLY)
-- note that the equality to on errors takes into account only the error level
-- and position (not the error text)
--
-- note that these comparisions are expensive (the positions contain the file
-- names as strings)
--
instance Eq Error where
(Error lvl1 pos1 _) == (Error lvl2 pos2 _) = lvl1 == lvl2 && pos1 == pos2
instance Ord Error where
(Error lvl1 pos1 _) < (Error lvl2 pos2 _) = pos1 < pos2
|| (pos1 == pos2 && lvl1 < lvl2)
e1 <= e2 = e1 < e2 || e1 == e2
-- produce an `Error', given its level, position, and a list of lines of
-- the error message that must not be empty (EXPORTED)
--
makeError :: ErrorLvl -> Position -> [String] -> Error
makeError = Error
-- inquire the error level (EXPORTED)
--
errorLvl :: Error -> ErrorLvl
errorLvl (Error lvl _ _) = lvl
-- converts an error into a string using a fixed format (EXPORTED)
--
-- * the list of lines of the error message must not be empty
--
-- * the format is
--
-- <fname>:<row>: (column <col>) [<err lvl>]
-- >>> <line_1>
-- <line_2>
-- ...
-- <line_n>
--
showError :: Error -> String
showError (Error lvl (fname, row, col) (l:ls)) =
let
prefix = fname ++ ":" ++ show (row::Int) ++ ": "
++ "(column "
++ show (col::Int)
++ ") ["
++ showErrorLvl lvl
++ "] "
showErrorLvl WarningErr = "WARNING"
showErrorLvl ErrorErr = "ERROR"
showErrorLvl FatalErr = "FATAL"
in
prefix ++ "\n"
++ " >>> " ++ l ++ "\n"
++ (indentMultilineString 2 . unlines) ls
showError (Error _ _ [] ) = interr "Errors: showError:\
\ Empty error message!"
errorAtPos :: Position -> [String] -> a
errorAtPos pos msg = (error . showError . makeError ErrorErr pos) msg
|
