-- settings
:set editor gvim

-- :. <file>
-- source commands from <file>
:undef .
:def . readFile

-- os&shell-independent pwd, ls
:undef pwd
:def pwd \_->return "System.Directory.getCurrentDirectory >>= putStrLn"
:undef ls
:def ls \p->return $ "mapM_ putStrLn =<< System.Directory.getDirectoryContents "++if (null p) then show "." else show p

-- a strict readFile, to prevent dangling handles/locks
let readFileNow f = readFile f >>= \t->length t `seq` return t

-- :redir <var> <cmd>
-- execute <cmd>, redirecting stdout to <var>
let redir varcmd = let { file = "ghci.tmp" } in case span (not . Data.Char.isSpace) varcmd of { (var,_:cmd) -> return $ unlines [":set -fno-print-bind-result","h <- IO.openFile "++show file++" IO.WriteMode","sto <- GHC.Handle.hDuplicate IO.stdout","GHC.Handle.hDuplicateTo h IO.stdout","IO.hClose h",cmd,"GHC.Handle.hDuplicateTo sto IO.stdout",var++" <- readFileNow "++show file]; _ -> return "putStrLn \"usage: :redir <var> <cmd>\"" } 
:undef redir
:def redir redir

-- :grep <pat> <cmd>
-- filter lines matching <pat> from the output of <cmd>
let grep patcmd = case span (not . Data.Char.isSpace) patcmd of { (pat,_:cmd) -> return $ unlines [":redir out "++cmd,"putStrLn $ unlines $ (\"\":) $ filter (Data.Maybe.isJust . Text.Regex.matchRegex (Text.Regex.mkRegex "++show pat++")) $ lines out"]; _ -> return "putStrLn \"usage: :grep <pat> <cmd>\""}
:undef grep
:def grep grep

-- :find <id>
-- call editor (:set editor) on definition of <id>
let find id = return $ unlines [":redir out :info "++id,"let ls = filter (Data.List.isInfixOf \"-- Defined\") $ lines out","let match = Text.Regex.matchRegex (Text.Regex.mkRegex \"-- Defined at ([^<:]*):([^:]*):\") $ head ls",":cmd return $ case (ls,match) of { (_:_,Just [mod,line]) -> (\":e +\"++line++\" \"++mod); _ -> \"\" }"]
:undef find
:def find find