-----------------------------------------------------------------------------
-- |
-- Module : CppIfdef
-- Copyright : 1999-2004 Malcolm Wallace
-- Licence : LGPL
--
-- Maintainer : Malcolm Wallace <Malcolm.Wallace@cs.york.ac.uk>
-- Stability : experimental
-- Portability : All
--
-- Perform a cpp.first-pass, gathering \#define's and evaluating \#ifdef's.
-- and \#include's.
-----------------------------------------------------------------------------
module Language.Preprocessor.Cpphs.CppIfdef
( cppIfdef -- :: FilePath -> [(String,String)] -> [String] -> Options
-- -> String -> [(Posn,String)]
) where
import Language.Preprocessor.Cpphs.SymTab
import Text.ParserCombinators.HuttonMeijer
-- import HashDefine
import Language.Preprocessor.Cpphs.Position (Posn,newfile,newline,newlines
,cppline,newpos)
import Language.Preprocessor.Cpphs.ReadFirst (readFirst)
import Language.Preprocessor.Cpphs.Tokenise (linesCpp,reslash)
import Language.Preprocessor.Cpphs.Options (BoolOptions(..))
import Language.Preprocessor.Cpphs.HashDefine(HashDefine(..),parseHashDefine
,expandMacro)
import Language.Preprocessor.Cpphs.MacroPass (preDefine,defineMacro)
import Char (isDigit)
import Numeric (readHex,readOct,readDec)
import System.IO.Unsafe (unsafePerformIO)
import IO (hPutStrLn,stderr)
-- | Run a first pass of cpp, evaluating \#ifdef's and processing \#include's,
-- whilst taking account of \#define's and \#undef's as we encounter them.
cppIfdef :: FilePath -- ^ File for error reports
-> [(String,String)] -- ^ Pre-defined symbols and their values
-> [String] -- ^ Search path for \#includes
-> BoolOptions -- ^ Options controlling output style
-> String -- ^ The input file content
-> [(Posn,String)] -- ^ The file after processing (in lines)
cppIfdef fp syms search options =
cpp posn defs search options Keep . (cppline posn:) . linesCpp
where
posn = newfile fp
defs = preDefine options syms
-- Previous versions had a very simple symbol table mapping strings
-- to strings. Now the #ifdef pass uses a more elaborate table, in
-- particular to deal with parameterised macros in conditionals.
-- | Internal state for whether lines are being kept or dropped.
-- In @Drop n b@, @n@ is the depth of nesting, @b@ is whether
-- we have already succeeded in keeping some lines in a chain of
-- @elif@'s
data KeepState = Keep | Drop Int Bool
-- | Return just the list of lines that the real cpp would decide to keep.
cpp :: Posn -> SymTab HashDefine -> [String] -> BoolOptions -> KeepState
-> [String] -> [(Posn,String)]
cpp _ _ _ _ _ [] = []
cpp p syms path options Keep (l@('#':x):xs) =
let ws = words x
cmd = head ws
line = tail ws
sym = head (tail ws)
rest = tail (tail ws)
def = defineMacro options (sym++" "++ maybe "1" id (un rest))
un v = if null v then Nothing else Just (unwords v)
keepIf p = if p then Keep else (Drop 1 False)
skipn syms' retain ud xs' =
let n = 1 + length (filter (=='\n') l) in
(if macros options && retain then ((p,reslash l):)
else (replicate n (p,"") ++)) $
cpp (newlines n p) syms' path options ud xs'
in case cmd of
"define" -> skipn (insertST def syms) True Keep xs
"undef" -> skipn (deleteST sym syms) True Keep xs
"ifndef" -> skipn syms False (keepIf (not (definedST sym syms))) xs
"ifdef" -> skipn syms False (keepIf (definedST sym syms)) xs
"if" -> skipn syms False
(keepIf (gatherDefined p syms (unwords line))) xs
"else" -> skipn syms False (Drop 1 False) xs
"elif" -> skipn syms False (Drop 1 True) xs
"endif" -> skipn syms False Keep xs
"pragma" -> skipn syms True Keep xs
('!':_) -> skipn syms False Keep xs -- \#!runhs scripts
"include"-> let (inc,content) =
unsafePerformIO (readFirst (file syms (unwords line))
p path
(warnings options))
in
cpp p syms path options Keep (("#line 1 "++show inc)
: linesCpp content
++ cppline (newline p): xs)
"warning"-> if warnings options then unsafePerformIO $ do
hPutStrLn stderr (l++"\nin "++show p)
return $ skipn syms False Keep xs
else skipn syms False Keep xs
"error" -> error (l++"\nin "++show p)
"line" | all isDigit sym
-> (if locations options then ((p,l):) else id) $
cpp (newpos (read sym) (un rest) p)
syms path options Keep xs
n | all isDigit n
-> (if locations options then ((p,l):) else id) $
cpp (newpos (read n) (un (tail ws)) p)
syms path options Keep xs
| otherwise
-> if warnings options then unsafePerformIO $ do
hPutStrLn stderr ("Warning: unknown directive #"++n
++"\nin "++show p)
return $
((p,l): cpp (newline p) syms path options Keep xs)
else
((p,l): cpp (newline p) syms path options Keep xs)
cpp p syms path options (Drop n b) (('#':x):xs) =
let ws = words x
cmd = head ws
delse | n==1 && b = Drop 1 b
| n==1 = Keep
| otherwise = Drop n b
dend | n==1 = Keep
| otherwise = Drop (n-1) b
delif s | n==1 && not b && gatherDefined p syms s
= Keep
| otherwise = Drop n b
skipn ud xs' =
let n' = 1 + length (filter (=='\n') x) in
replicate n' (p,"")
++ cpp (newlines n' p) syms path options ud xs'
in
if cmd == "ifndef" ||
cmd == "if" ||
cmd == "ifdef" then skipn (Drop (n+1) b) xs
else if cmd == "elif" then skipn (delif (unwords (tail ws))) xs
else if cmd == "else" then skipn delse xs
else if cmd == "endif" then skipn dend xs
else skipn (Drop n b) xs
-- define, undef, include, error, warning, pragma, line
cpp p syms path options Keep (x:xs) =
let p' = newline p in seq p' $
(p,x): cpp p' syms path options Keep xs
cpp p syms path options d@(Drop _ _) (_:xs) =
let p' = newline p in seq p' $
(p,""): cpp p' syms path options d xs
----
gatherDefined :: Posn -> SymTab HashDefine -> String -> Bool
gatherDefined p st inp =
case papply (parseBoolExp st) inp of
[] -> error ("Cannot parse #if directive in file "++show p)
[(b,_)] -> b
_ -> error ("Ambiguous parse for #if directive in file "++show p)
parseBoolExp :: SymTab HashDefine -> Parser Bool
parseBoolExp st =
do a <- parseExp1 st
skip (string "||")
b <- first (skip (parseBoolExp st))
return (a || b)
+++
parseExp1 st
parseExp1 :: SymTab HashDefine -> Parser Bool
parseExp1 st =
do a <- parseExp0 st
skip (string "&&")
b <- first (skip (parseExp1 st))
return (a && b)
+++
parseExp0 st
parseExp0 :: SymTab HashDefine -> Parser Bool
parseExp0 st =
do skip (string "defined")
sym <- parens parseSym
return (definedST sym st)
+++
do parens (parseBoolExp st)
+++
do skip (char '!')
a <- parseExp0 st
return (not a)
+++
do sym1 <- parseSymOrCall st
op <- parseOp st
sym2 <- parseSymOrCall st
return (op (safeRead sym1) (safeRead sym2))
+++
do sym <- parseSymOrCall st
case safeRead sym of
0 -> return False
_ -> return True
where
safeRead s =
case s of
'0':'x':s' -> number readHex s'
'0':'o':s' -> number readOct s'
_ -> number readDec s
number rd s =
case rd s of
[] -> 0 :: Integer
((n,_):_) -> n :: Integer
parseOp :: SymTab HashDefine -> Parser (Integer -> Integer -> Bool)
parseOp _ =
do skip (string ">=")
return (>=)
+++
do skip (char '>')
return (>)
+++
do skip (string "<=")
return (<=)
+++
do skip (char '<')
return (<)
+++
do skip (string "==")
return (==)
+++
do skip (string "!=")
return (/=)
parseSymOrCall :: SymTab HashDefine -> Parser String
parseSymOrCall st =
do sym <- skip parseSym
args <- parens (parseSymOrCall st `sepby` skip (char ','))
return (convert sym args)
+++
do sym <- skip parseSym
return (convert sym [])
where
convert sym args =
case lookupST sym st of
Nothing -> sym
Just (a@SymbolReplacement{}) -> recursivelyExpand st (replacement a)
Just (a@MacroExpansion{}) -> expandMacro a args False
recursivelyExpand :: SymTab HashDefine -> String -> String
recursivelyExpand st inp =
case papply (parseSymOrCall st) inp of
[(b,_)] -> b
_ -> inp
parseSym :: Parser String
parseSym = many1 (alphanum+++char '\''+++char '`')
parens p = bracket (skip (char '(')) (skip p) (skip (char ')'))
-- | Determine filename in \#include
file :: SymTab HashDefine -> String -> String
file st name =
case name of
('"':ns) -> init ns
('<':ns) -> init ns
_ -> let ex = recursivelyExpand st name in
if ex == name then name else file st ex