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|
-----------------------------------------------------------------------------
-- |
-- Module : Position
-- Copyright : 2000-2004 Malcolm Wallace
-- Licence : LGPL
--
-- Maintainer : Malcolm Wallace <Malcolm.Wallace@cs.york.ac.uk>
-- Stability : experimental
-- Portability : All
--
-- Simple file position information, with recursive inclusion points.
-----------------------------------------------------------------------------
module Position
( Posn(..)
, newfile
, addcol, newline, tab, newlines, newpos
, cppline
, filename, lineno, directory
) where
-- | Source positions contain a filename, line, column, and an
-- inclusion point, which is itself another source position,
-- recursively.
data Posn = Pn String !Int !Int (Maybe Posn)
deriving (Eq)
instance Show Posn where
showsPrec _ (Pn f l c i) = showString f .
showString " at line " . shows l .
showString " col " . shows c .
( case i of
Nothing -> id
Just p -> showString "\n used by " .
shows p )
-- | Constructor
newfile :: String -> Posn
newfile name = Pn name 1 1 Nothing
-- | Updates
addcol :: Int -> Posn -> Posn
addcol n (Pn f r c i) = Pn f r (c+n) i
newline, tab :: Posn -> Posn
newline (Pn f r _ i) = Pn f (r+1) 1 i
tab (Pn f r c i) = Pn f r (((c`div`8)+1)*8) i
newlines :: Int -> Posn -> Posn
newlines n (Pn f r _ i) = Pn f (r+n) 1 i
newpos :: Int -> Maybe String -> Posn -> Posn
newpos r Nothing (Pn f _ c i) = Pn f r c i
newpos r (Just ('"':f)) (Pn _ _ c i) = Pn (init f) r c i
newpos r (Just f) (Pn _ _ c i) = Pn f r c i
-- | Projections
lineno :: Posn -> Int
filename :: Posn -> String
directory :: Posn -> FilePath
lineno (Pn _ r _ _) = r
filename (Pn f _ _ _) = f
directory (Pn f _ _ _) = dirname f
-- | cpp-style printing
cppline :: Posn -> String
cppline (Pn f r _ _) = "#line "++show r++" "++show f
-- Strip non-directory suffix from file name (analogous to the shell
-- command of the same name).
dirname :: String -> String
dirname = reverse . safetail . dropWhile (not.(`elem`"\\/")) . reverse
where safetail [] = []
safetail (_:x) = x
|
