tock-mirror/common/Metadata.hs
Neil Brown c97d1d00c8 Changed the error type from String to ErrorReport throughout the code
ErrorReport is of type (Maybe Meta, String), thereby adding an optional code position to error messages.

Die has been changed so that die and dieP are now implemented in terms of dieReport (:: ErrorReport -> m a).  This involved changing less code than changing die to be of type ErrorReport -> m a.  All that had to be changed directly was that Die instances now implement dieReport instead of die.

Any bits of code that "caught" errors has been changed so that it handles ErrorReport instead of String.  This ErrorReport is eventually, in Main, passed to dieIO, which will soon be changed to read the file in and provide the context.  Accordingly, MonadIO m has been added as a constraint to dieIO, and dieInternal has been changed to no longer use dieIO (because really we can't add the MonadIO constraint to dieInternal).

Various error messages have been changed.  Notably, all instances of fail in ParseOccam have been changed to use die or, wherever possible, dieP.  A similar thing has been done in EvalConstants and EvalLiterals.
2007-09-18 10:17:38 +00:00

86 lines
2.5 KiB
Haskell

{-
Tock: a compiler for parallel languages
Copyright (C) 2007 University of Kent
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 2 of the License, or (at your
option) any later version.
This program 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
General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program. If not, see <http://www.gnu.org/licenses/>.
-}
-- | Metadata -- i.e. source position.
module Metadata where
{-! global : Haskell2Xml !-}
import Data.Generics
import Text.Printf
import Text.Read
import Utils
data Meta = Meta {
metaFile :: Maybe String,
metaLine :: Int,
metaColumn :: Int
}
deriving (Typeable, Data)
emptyMeta :: Meta
emptyMeta = Meta {
metaFile = Nothing,
metaLine = 0,
metaColumn = 0
}
instance Show Meta where
show m =
case metaFile m of
Just s -> s ++ ":" ++ show (metaLine m) ++ ":" ++ show (metaColumn m)
Nothing -> "no source position"
--emptyMeta is equal to any meta tag:
instance Eq Meta where
(==) a b =
if ((metaFile a == Nothing) && (metaLine a == 0) && (metaColumn a == 0)) then True else
if ((metaFile b == Nothing) && (metaLine b == 0) && (metaColumn b == 0)) then True else
((metaFile a == metaFile b) && (metaLine a == metaLine b) && (metaColumn a == metaColumn b))
-- | Encode a Meta as the prefix of a string.
packMeta :: Meta -> String -> String
packMeta m s
= case metaFile m of
Nothing -> s
Just fn -> printf "~%d\0%d\0%s\0%s"
(metaLine m) (metaColumn m) fn s
-- | Extract a Meta (encoded by packMeta) from a String.
unpackMeta :: String -> (Maybe Meta, String)
unpackMeta ('~':s) = (Just m, rest)
where
(ls, _:s') = break (== '\0') s
(cs, _:s'') = break (== '\0') s'
(fn, _:rest) = break (== '\0') s''
m = emptyMeta {
metaFile = Just fn,
metaLine = read ls,
metaColumn = read cs
}
unpackMeta s = (Nothing, s)
-- | Find the first Meta value in some part of the AST.
findMeta :: (Data t, Typeable t) => t -> Meta
findMeta e = if null metaList then emptyMeta else head metaList
where
metaList = gmapQ (mkQ emptyMeta findMeta') e
findMeta' :: Meta -> Meta
findMeta' m = m