(*****************************************************************************
 * su4sml --- an SML repository for managing (Secure)UML/OCL models
 *             http://projects.brucker.ch/su4sml/
 *                                                                            
 * polyml.sml --- interactive eval 
 * This file is part of su4sml.
 *
 * Copyright (c) 2005-2007, ETH Zurich, Switzerland
 *
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 *       with the distribution.
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 *
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 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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 ******************************************************************************)
(* $Id$ *)

structure CompilerExt : COMPILER_EXT = 
struct

exception EvalNotSupported
fun drop_last [] = []
  | drop_last [x] = []
  | drop_last (x :: xs) = x :: drop_last xs;

fun eval verbose txt =
    let 
	fun eval_fh (print, err) verbose txt =
	    let
		val in_buffer = ref (SML90.explode txt);
		val out_buffer = ref ([]: string list);
		fun output () = SML90.implode (drop_last (rev (! out_buffer)));
		    
		fun get () =
		    (case ! in_buffer of
			 [] => ""
		       | c :: cs => (in_buffer := cs; c));
		fun put s = out_buffer := s :: ! out_buffer;
		    
		fun exec () =
		    (case ! in_buffer of
			 [] => ()
		       | _ => (PolyML.compiler (get, put) (); exec ()));
	    in
		exec () handle exn => (err (output ()); raise exn);
		if verbose then print (output ()) else ()
	    end
    in	
	eval_fh (fn s => print (s^"\n"), fn s => Logger.error (s^"\n")) verbose txt
    end

fun exnHistory _ = []

end