structure Convert = struct    fun manglefilename s = s     (* Lexer of stream *)    fun createLexerStream (is : BasicIO.instream) =	Lexing.createLexer (fn buff => fn n => Nonstdio.buff_input is buff 0 n)     fun parseFile lexbuf = Parser.Seq Scanner.Token lexbuf     val quiet = ref false    fun chat s = if !quiet then ()		 else (print s; print "\n")      local 	open Parser Substring	val hasStruc = List.exists (fn STRUCTURE => true | _ => false)  	val hasSig   = List.exists (fn SIGNATURE => true | _ => false)  	val sign     = all "signature"	val stru     = all "structure"	val ends     = all "\nend\n"	val isComment = isPrefix "(*"	val allWS    = foldl (fn (c,res) => res andalso Char.isSpace c) true    in 	fun roll (s :: sl) = if isComment s then s :: ends :: sl			     else if allWS s then s :: roll sl				  else ends :: s :: sl	  | roll _         = [ends]  	fun ending rollback sl =	    if not rollback then ends :: sl	    else roll sl 	fun toSub rollback seq subs =	    let fun getSub x y = slice(subs,x,SOME(y-x))		fun loop (SIGNATURE :: ts) acc = loop ts (sign :: acc)		  | loop (STRUCTURE :: ts) acc = loop ts (stru :: acc)		  | loop (MLSTUFF(x,y) :: ts) acc = loop ts (getSub x y :: acc)		  | loop (COMMENT(x,y) :: ts) acc = loop ts (getSub x y :: acc)		  | loop _ acc = acc	    in  rev(ending rollback (loop seq []))	    end		fun unitname filename = Path.base(Path.file filename) 	fun addStruc withsig seq filename =	    let val dev = TextIO.openIn filename		val s   = all (TextIO.inputAll dev)	    in  if hasStruc seq then string s		else let val cont = toSub false seq s			 val unit = unitname filename			 val sign = if withsig then [" :> ",unit," = \nstruct\n"]				    else [" = \nstruct\n"]			 val beg = all(String.concat("structure "::unit::sign))		     in  concat(beg :: cont)		     end	    end  	fun addSig rollback seq filename =	    let val dev = TextIO.openIn filename		val s   = all (TextIO.inputAll dev)	    in  if hasSig seq then string s		else let val cont = toSub rollback seq s			 val unit = unitname filename			 val beg  = all("signature "^unit^" = \nsig\n")		     in  concat(beg :: cont)		     end	    end	    end     fun read filename =	let	val is     = BasicIO.open_in filename	    val lexbuf = createLexerStream is	    val seq    = parseFile lexbuf	    val _      = BasicIO.close_in is	in  seq	end     fun write outdir filename content =	let val filen = Path.concat(outdir, Path.file filename)	    val dev   = TextIO.openOut filen 	in  TextIO.output(dev, content)	    ; TextIO.closeOut dev	end     fun dostuff doit filename outdir =	let val seq = read filename	    val cont = doit seq filename	in  write outdir filename cont	end     fun hasSig filename =	let val b = Path.base filename	    val s = Path.joinBaseExt{base = b, ext = SOME"sig"}	in  FileSys.access(s,[])	end     fun processfile rollback outdir filename = 	(case Path.ext filename of	     SOME"sig" => dostuff (addSig rollback) filename outdir	   | SOME"sml" => dostuff (addStruc (hasSig filename)) filename outdir	   | SOME"mlp" => dostuff (addStruc (hasSig filename)) filename outdir	   | _         => print("Don't know how to handle "^filename^"\n"))	handle Fail msg => app print ["Error processing file: ", filename,				      "\n", msg, "\n"]	     | OS.SysErr (msg, err) =>	          let val msg = case err of 		                    SOME e => OS.errorMsg e				  | NONE   => msg		  in		      app print ["OS Error processing file: ",				 filename, "\n", msg, "\n"]		  end     fun getOpt option def ls =	let fun get (opt :: (rest as arg :: xs)) =		if opt = option then (arg, xs)		else let val (res, ls) = get rest		     in  (res, opt :: ls)		     end	      | get ls = (def, ls)	in  get ls	end     fun main args =	let fun eq x y = x = y	    val (rb, args) = List.partition (eq "-rollback") args	    val rollback = not (null rb)	    val (q, args)  = List.partition (eq "-q") args	    val _ = quiet := not (null q)	    fun outdir ("-D" :: d :: ls) = (d, ls)	      | outdir (s :: ls)         = let val (d,ls) = outdir ls					   in  (d, s::ls)					   end	      | outdir []                = (".",[])	    val (dir, files) = getOpt "-D" "." args	in  app (processfile rollback dir) files	end     val _ = 	case CommandLine.arguments() of	    [] => print "usage: convert [-rollback] [-D outdir] files\n"	  | args => main args end