tock-mirror/common/Metadata.hs

79 lines
2.2 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
data Meta = Meta {
metaFile :: Maybe String,
metaLine :: Int,
metaColumn :: Int
}
deriving (Typeable, Data, Ord, Eq)
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"
-- | 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 = case cast e of
Just m -> m
Nothing -> if null metaList then emptyMeta else head metaList
where
metaList = gmapQ (mkQ emptyMeta findMeta') e
findMeta' :: Meta -> Meta
findMeta' m = m