From 968410ef256f49be0a3ba5de087f1ec776c3f395 Mon Sep 17 00:00:00 2001
From: Duncan Coutts <duncan@haskell.org>
Date: Sun, 30 Dec 2007 01:25:30 +0000
Subject: [PATCH] Refactor unlit code to improve error and line pragma handling
And to make it more like the original code that classified lines separately
from checking and transforming them.
---
Distribution/Simple/Hugs.hs | 10 +-
Distribution/Simple/PreProcess.hs | 2 +-
Distribution/Simple/PreProcess/Unlit.hs | 141 +++++++++++++++---------
3 files changed, 94 insertions(+), 59 deletions(-)
diff --git a/Distribution/Simple/Hugs.hs b/Distribution/Simple/Hugs.hs
index a83fd411c5..5bfccb0151 100644
--- a/Distribution/Simple/Hugs.hs
+++ b/Distribution/Simple/Hugs.hs
@@ -249,7 +249,9 @@ build pkg_descr lbi verbosity = do
readHaskellFile :: FilePath -> IO String
readHaskellFile file = do
text <- readFile file
- return $ if ".lhs" `isSuffixOf` file then unlit file text else text
+ if ".lhs" `isSuffixOf` file
+ then either return die (unlit file text)
+ else return text
-- ------------------------------------------------------------
-- * options in source files
@@ -265,11 +267,13 @@ getOptionsFromSource
)
getOptionsFromSource file = do
text <- readFile file
+ text' <- if ".lhs" `isSuffixOf` file
+ then either return die (unlit file text)
+ else return text
return $ foldr appendOptions ([],[],[]) $ map getOptions $
takeWhileJust $ map getPragma $
filter textLine $ map (dropWhile isSpace) $ lines $
- stripComments True $
- if ".lhs" `isSuffixOf` file then unlit file text else text
+ stripComments True text'
where textLine [] = False
textLine ('#':_) = False
textLine _ = True
diff --git a/Distribution/Simple/PreProcess.hs b/Distribution/Simple/PreProcess.hs
index 425e2f3cc5..b0fbdb7d26 100644
--- a/Distribution/Simple/PreProcess.hs
+++ b/Distribution/Simple/PreProcess.hs
@@ -268,7 +268,7 @@ ppUnlit =
platformIndependent = True,
runPreProcessor = mkSimplePreProcessor $ \inFile outFile _verbosity -> do
contents <- readFile inFile
- writeFile outFile (unlit inFile contents)
+ either (writeFile outFile) die (unlit inFile contents)
}
ppCpp :: BuildInfo -> LocalBuildInfo -> PreProcessor
diff --git a/Distribution/Simple/PreProcess/Unlit.hs b/Distribution/Simple/PreProcess/Unlit.hs
index bf56adb046..c947e839de 100644
--- a/Distribution/Simple/PreProcess/Unlit.hs
+++ b/Distribution/Simple/PreProcess/Unlit.hs
@@ -10,26 +10,70 @@
-- Remove the \"literal\" markups from a Haskell source file, including
-- \"@>@\", \"@\\begin{code}@\", \"@\\end{code}@\", and \"@#@\"
+-- This version is interesting because instead of striping comment lines, it
+-- turns them into "-- " style comments. This allows using haddock markup
+-- in literate scripts without having to use "> --" prefix.
+
module Distribution.Simple.PreProcess.Unlit (unlit,plain) where
import Data.Char
import Data.List
+data Classified = BirdTrack String | Blank String | Ordinary String
+ | Line !Int String | CPP String
+ | BeginCode | EndCode
+ -- output only:
+ | Error String | Comment String
+
-- | No unliteration.
plain :: String -> String -> String
plain _ hs = hs
+classify :: String -> Classified
+classify ('>':s) = BirdTrack s
+classify ('#':s) = case tokens s of
+ (line:file:_) | all isDigit line
+ && length file >= 2
+ && head file == '"'
+ && last file == '"'
+ -> Line (read line) (tail (init file))
+ _ -> CPP s
+ where tokens = unfoldr $ \str -> case lex str of
+ (t@(_:_), str'):_ -> Just (t, str')
+ _ -> Nothing
+classify ('\\':s)
+ | s `isPrefixOf` "begin{code}" = BeginCode
+ | s `isPrefixOf` "end{code}" = EndCode
+classify s | all isSpace s = Blank s
+classify s = Ordinary s
+
+unclassify :: Classified -> String
+unclassify (BirdTrack s) = ' ':s
+unclassify (Blank s) = s
+unclassify (Ordinary s) = s
+unclassify (Line n file) = "# " ++ show n ++ " " ++ show file
+unclassify (CPP s) = '#':s
+unclassify (Comment s) = "-- " ++ s
+
-- | 'unlit' takes a filename (for error reports), and transforms the
-- given string, to eliminate the literate comments from the program text.
-unlit :: FilePath -> String -> String
-unlit file lhs = (unlines . classify file) (inlines lhs)
+unlit :: FilePath -> String -> Either String String
+unlit file = either (Left . unlines
+ . map unclassify)
+ Right
+ . checkErrors
+ . reclassify
+ . map classify
+ . inlines
-
-isBirdTrack = isPrefixOf ">"
-isCpp = isPrefixOf "#"
-isCodeStart = isPrefixOf "\\begin{code}"
-isCodeEnd = isPrefixOf "\\end{code}"
-isEmptyLine = all isSpace
+ where checkErrors ls = case [ e | Error e <- ls ] of
+ [] -> Left ls
+ (message:_) -> Right (f ++ ":" ++ show n ++ ": " ++ message)
+ where (f, n) = errorPos file 1 ls
+ errorPos f n [] = (f, n)
+ errorPos f n (Error _:_) = (f, n)
+ errorPos _ _ (Line n' f':ls) = errorPos f' n' ls
+ errorPos f n (_ :ls) = errorPos f (n+1) ls
-- Here we model a state machine, with each state represented by
-- a local function. We only have four states (well, five,
@@ -40,57 +84,44 @@ isEmptyLine = all isSpace
-- Each state represents the type of line that was last read
-- i.e. are we in a comment section, or a latex-code section,
-- or a bird-code section, etc?
-classify :: String -> [String] -> [String]
-classify file [] = []
-classify file lines = blank lines 1 -- begin in blank state
+reclassify :: [Classified] -> [Classified]
+reclassify = blank -- begin in blank state
where
- err n msg = error ("In file "++file++" at line "++show n++": "++msg++".")
- dropBird _ ('>':' ':x) = x
- dropBird _ ('>':x) = x
- dropBird n _ = err n "expecting '>' at start of line"
- mkComment x = "-- " ++ x
-
- transition classification [] _ _ = [classification]
- -- First case guarantee that xs is never null,
- -- so state functions can assume that too.
- transition classification xs n state = classification : state xs (n+1)
-
- latex (x:xs) n
- | isCodeEnd x = transition "" xs n comment
- | isCodeStart x = err n "\\begin{code} in code section"
- | otherwise = transition x xs n latex
-
- blank (x:xs) n
- | isCodeEnd x = err n "\\end{code} without \\begin{code}"
- | isCodeStart x = transition "" xs n latex
- | isCpp x = transition x xs n blank
- | isBirdTrack x = transition (dropBird n x) xs n bird
- | isEmptyLine x = transition "" xs n blank
- | otherwise = transition (mkComment x) xs n comment
+ latex [] = []
+ latex (EndCode :ls) = Blank "" : comment ls
+ latex (BeginCode :_ ) = [Error "\\begin{code} in code section"]
+ latex (BirdTrack l:ls) = Ordinary ('>':l) : bird ls
+ latex ( l:ls) = l : latex ls
- bird (x:xs) n
- | isCodeEnd x = err n "\\end{code} without \\begin{code}"
- | isCodeStart x = transition "" xs n latex
- | isCpp x = transition x xs n bird
- | isBirdTrack x = transition (dropBird n x) xs n bird
- | isEmptyLine x = transition "" xs n blank
- | otherwise = err n "program line before comment line"
+ blank [] = []
+ blank (EndCode :_ ) = [Error "\\end{code} without \\begin{code}"]
+ blank (BeginCode :ls) = Blank "" : latex ls
+ blank (BirdTrack l:ls) = BirdTrack l : bird ls
+ blank (Ordinary l:ls) = Comment l : comment ls
+ blank ( l:ls) = l : blank ls
- comment (x:xs) n
- | isCodeEnd x = err n "\\end{code} without \\begin{code}"
- | isCodeStart x = transition "" xs n latex
- | isCpp x = transition x xs n comment
- | isBirdTrack x = err n "comment line before program line"
- -- special case here: a truly empty line will terminate
- -- a comment section (and send us into the "blank" state)
- -- but a line containing whitespace will be treated as a
- -- comment (prefixed with "-- "), unless it is followed by
- -- a program line, in which case it is really blank.
- | null x = transition "" xs n blank
- | isEmptyLine x && null xs = transition (mkComment x) xs n comment
- | isEmptyLine x && isBirdTrack (head xs) = transition "" xs n blank
- | otherwise = transition (mkComment x) xs n comment
+ bird [] = []
+ bird (EndCode :_ ) = [Error "\\end{code} without \\begin{code}"]
+ bird (BeginCode :ls) = Blank "" : latex ls
+ bird (Blank l :ls) = Blank l : blank ls
+ bird (Ordinary _:_ ) = [Error "program line before comment line"]
+ bird ( l:ls) = l : bird ls
+ comment [] = []
+ comment (EndCode :_ ) = [Error "\\end{code} without \\begin{code}"]
+ comment (BeginCode :ls) = Blank "" : latex ls
+ comment (CPP l :ls) = CPP l : comment ls
+ comment (BirdTrack _:_ ) = [Error "comment line before program line"]
+ -- special case here: a truly empty line will terminate
+ -- a comment section (and send us into the "blank" state)
+ comment (Blank "" :ls) = Blank "" : blank ls
+ -- but a line containing whitespace will be treated as a
+ -- comment (prefixed with "-- "), unless it is followed by
+ -- a program line, in which case it is really blank.
+ comment (Blank l:ls@(BirdTrack _:_)) = Blank l : blank ls
+ comment (Blank l:ls) = Comment l : comment ls
+ comment (Line n f :ls) = Line n f : comment ls
+ comment (Ordinary l:ls) = Comment l : comment ls
-- Re-implementation of 'lines', for better efficiency (but decreased laziness).
-- Also, importantly, accepts non-standard DOS and Mac line ending characters.
--
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