{- this module coordinates the whole shebang.

Parses input and plucks out data and newtype declarations and

processor commands.

The commands are combined with the parsed data, and if any data is missing,

derive goes hunting for it, looking in

the path variable DERIVEPATH. Derive searches recusively though modules

imported until all the types needed are found, or it runs out of links,

which causes an error -}

module ChaseImports where

import RuleUtils (Tag)

import DataP

import CommandP

import ParseLib2

import System

import List

import Monad

import GenUtil

--GHC version

try x = catch (x >>= return . Right) (return . Left)

-- Parser - extract data and newtypes from code

type ToDo = [([Tag],Data)]

parser :: String -> ToDo

parser = sanitycheck . papply p (0,0) . \s -> ((0,0),s)

where

p = parse . skipUntilOff $ statement +++ command

statement = do d <- datadecl +++ newtypedecl

ts <- opt local

return (ts,d)

sanitycheck [] = error "***Error: no DrIFT directives found\n"

sanitycheck [(x,_)] = x

sanitycheck ((x,_):_) = error "***Error: ambiguous DriFT directives?"

-------Go Hunting for files, recursively ----------------------------------

chaseImports :: String -> ToDo -> IO ToDo

chaseImports txt dats = do

(left,found) <- chaseImports' txt dats

if (not . null) left then error ("can't find type " ++ show left)

else return found

chaseImports' :: String -> ToDo -> IO (ToDo,ToDo)

chaseImports' text dats =

case papply (parse header) (0,-1) ((0,0),text) of

[] -> return (dats,[])

(modnames:_) -> foldM action (dats,[]) (fst modnames)

where

action :: (ToDo,ToDo) -> FilePath -> IO (ToDo,ToDo)

action (dats,done) m | null dats = return ([],done)

| otherwise = do

mp <- ioM $ getEnv "DERIVEPATH"

let paths = maybe [] breakPaths mp

c <- findModule paths m

let (found,rest) = scanModule dats c

return (rest, done ++ found) -- finished

-- only one level of imports is now supported for more speed!

-- break DERIVEPATH into it's components

breakPaths :: String -> [String]

breakPaths x = case break (==':') x of

(p,(_:pp)) -> p: breakPaths pp

(p,[]) -> [p]

-- search though paths, using try

findModule :: [String] -> String -> IO String

findModule paths modname = let

action p = try $ do

h <- readFile p

return (h,p)

fnames = combine paths hiracle_modname

hiracle_modname = map (\x -> if x == '.' then '/' else x) modname

isLeft (Left _ ) = True

isLeft _ = False

in do

hh <- mapM action fnames

let (h,p) = case dropWhile (isLeft) hh of

((Right h):_) -> h

_ -> error ("can't find module " ++ modname)

return h

-- generate filepaths by combining module names with different suffixes.

-- Note : Dedicated Hugs-only users may wish to remove ".hi" from the list of

-- file types to search.

combine :: [String] -> String -> [FilePath]

combine paths modname = [p++'/':f| f <- toFile modname, p <- ("." :paths)]

where

toFile :: String -> [String]

toFile l = [l++".hs",l++".lhs",l++".hi"]

-- pluck out the bits of interest

scanModule :: ToDo -> String -> (ToDo,ToDo)

scanModule dats txt = let

newDats = filter isData . parse $ txt

parse l = map snd . parser $ l

in (resolve newDats dats ([],[]))

-- update what's still missing

resolve :: [Data] -> ToDo -> (ToDo,ToDo) -> (ToDo,ToDo)

resolve _ [] acc = acc

resolve parsed (tv:tt) p@(local, imports) =

case tv of

(tags, TypeName t) -> case filter ((== t) . name) parsed of

[x] -> resolve parsed tt ((tags, x) : local, imports)

_ -> resolve parsed tt (local, tv : imports)

_ -> resolve parsed tt p

-- utils -- this should be the sort of thing automatically generated !!

isData D{} = True

isData _ = False