ltl2tgba.cc

// Copyright (C) 2007, 2008, 2009, 2010 Laboratoire de Recherche et
// Dveloppement de l'Epita (LRDE).
// Copyright (C) 2003, 2004, 2005, 2006, 2007 Laboratoire d'Informatique de
// Paris 6 (LIP6), dpartement Systmes Rpartis
// Coopratifs (SRC), Universit Pierre et Marie Curie.
//
// This file is part of Spot, a model checking library.
//
// Spot is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// Spot is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
// License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Spot; see the file COPYING.  If not, write to the Free
// Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
// 02111-1307, USA.

#include <iostream>
#include <iomanip>
#include <cassert>
#include <fstream>
#include <string>
#include <cstdlib>
#include "ltlvisit/contain.hh"
#include "ltlvisit/tostring.hh"
#include "ltlvisit/apcollect.hh"
#include "ltlast/allnodes.hh"
#include "ltlparse/public.hh"
#include "tgbaalgos/ltl2tgba_lacim.hh"
#include "tgbaalgos/ltl2tgba_fm.hh"
#include "tgbaalgos/ltl2taa.hh"
#include "tgba/bddprint.hh"
#include "tgbaalgos/save.hh"
#include "tgbaalgos/dotty.hh"
#include "tgbaalgos/lbtt.hh"
#include "tgba/tgbatba.hh"
#include "tgba/tgbasgba.hh"
#include "tgba/tgbaproduct.hh"
#include "tgba/futurecondcol.hh"
#include "tgbaalgos/reducerun.hh"
#include "tgbaparse/public.hh"
#include "neverparse/public.hh"
#include "tgbaalgos/dupexp.hh"
#include "tgbaalgos/minimize.hh"
#include "tgbaalgos/neverclaim.hh"
#include "tgbaalgos/reductgba_sim.hh"
#include "tgbaalgos/replayrun.hh"
#include "tgbaalgos/rundotdec.hh"
#include "tgbaalgos/sccfilter.hh"
#include "tgbaalgos/safety.hh"
#include "tgbaalgos/eltl2tgba_lacim.hh"
#include "tgbaalgos/gtec/gtec.hh"
#include "eltlparse/public.hh"
#include "misc/timer.hh"

#include "tgbaalgos/stats.hh"
#include "tgbaalgos/scc.hh"
#include "tgbaalgos/emptiness_stats.hh"

std::string
ltl_defs()
{
  std::string s = "\
X=(0 1 true	   \
   1 2 $0	   \
   accept 2)	   \
U=(0 0 $0	   \
   0 1 $1	   \
   accept 1)	   \
G=(0 0 $0)	   \
F=U(true, $0)	   \
W=G($0)|U($0, $1)  \
R=!U(!$0, !$1)     \
M=F($0)&R($0, $1)";
  return s;
}

void
syntax(char* prog)
{
  // Display the supplied name unless it appears to be a libtool wrapper.
  char* slash = strrchr(prog, '/');
  if (slash && (strncmp(slash + 1, "lt-", 3) == 0))
    prog = slash + 4;

  std::cerr << "Usage: "<< prog << " [-f|-l|-le|-taa] [OPTIONS...] formula"
	    << std::endl
            << "       "<< prog << " [-f|-l|-le|-taa] -F [OPTIONS...] file"
	    << std::endl
            << "       "<< prog << " -X [OPTIONS...] file" << std::endl
	    << std::endl

            << "Translate an LTL formula into an automaton, or read the "
	    << "automaton from a file." << std::endl
	    << "Optionally multiply this automaton by another"
	    << " automaton read from a file." << std::endl
            << "Output the result in various formats, or perform an emptiness "
            << "check." << std::endl
	    << std::endl

            << "Input options:" << std::endl
            << "  -F    read the formula from a file, not from the command line"
	    << std::endl
	    << "  -X    do not compute an automaton, read it from a file"
	    << std::endl
	    << "  -XN   do not compute an automaton, read it from a"
	    << " neverclaim file" << std::endl
	    << "  -Pfile  multiply the formula automaton with the automaton"
	    << " from `file'"
	    << std::endl
	    << std::endl

	    << "Translation algorithm:" << std::endl
            << "  -f    use Couvreur's FM algorithm for LTL"
	    << "(default)"
	    << std::endl
            << "  -l    use Couvreur's LaCIM algorithm for LTL "
	    << std::endl
	    << "  -le   use Couvreur's LaCIM algorithm for ELTL"
	    << std::endl
            << "  -taa  use Tauriainen's TAA-based algorithm for LTL"
	    << std::endl
	    << std::endl

	    << "Options for Couvreur's FM algorithm (-f):" << std::endl
	    << "  -fr1  use -r1 (see below) at each step of FM" << std::endl
	    << "  -fr2  use -r2 (see below) at each step of FM" << std::endl
	    << "  -fr3  use -r3 (see below) at each step of FM" << std::endl
	    << "  -fr4  use -r4 (see below) at each step of FM" << std::endl
	    << "  -fr5  use -r5 (see below) at each step of FM" << std::endl
	    << "  -fr6  use -r6 (see below) at each step of FM" << std::endl
	    << "  -fr7  use -r7 (see below) at each step of FM" << std::endl
            << "  -L    fair-loop approximation (implies -f)" << std::endl
            << "  -p    branching postponement (implies -f)" << std::endl
            << "  -U[PROPS]  consider atomic properties of the formula as "
	    << "exclusive events, and" << std::endl
	    << "        PROPS as unobservables events (implies -f)"
	    << std::endl
            << "  -x    try to produce a more deterministic automaton "
	    << "(implies -f)" << std::endl
	    << "  -y    do not merge states with same symbolic representation "
	    << "(implies -f)" << std::endl
	    << std::endl

	    << "Options for Couvreur's LaCIM algorithm (-l or -le):"
	    << std::endl
	    << "  -a    display the acceptance_conditions BDD, not the "
	    << "reachability graph"
	    << std::endl
	    << "  -A    same as -a, but as a set" << std::endl
	    << "  -lo   pre-define standard LTL operators as automata "
	    << "(implies -le)" << std::endl
	    << "  -r    display the relation BDD, not the reachability graph"
	    << std::endl
	    << "  -R    same as -r, but as a set" << std::endl
	    << "  -R3b  symbolically prune unaccepting SCC from BDD relation"
	    << std::endl
	    << std::endl

	    << "Options for Tauriainen's TAA-based algorithm (-taa):"
	    << std::endl
	    << "  -c    enable language containment checks (implies -taa)"
	    << std::endl
	    << std::endl

	    << "Formula simplification (before translation):"
	    << std::endl
	    << "  -r1   reduce formula using basic rewriting" << std::endl
	    << "  -r2   reduce formula using class of eventuality and "
	    << "universality" << std::endl
	    << "  -r3   reduce formula using implication between "
	    << "sub-formulae" << std::endl
	    << "  -r4   reduce formula using all above rules" << std::endl
	    << "  -r5   reduce formula using tau03" << std::endl
	    << "  -r6   reduce formula using tau03+" << std::endl
	    << "  -r7   reduce formula using tau03+ and -r4" << std::endl
	    << "  -rd   display the reduced formula" << std::endl
	    << std::endl

	    << "Automaton degeneralization (after translation):"
	    << std::endl
            << "  -lS   move generalized acceptance conditions to states "
	    << "(SGBA)" << std::endl
	    << "  -D    degeneralize the automaton as a TBA" << std::endl
	    << "  -DS   degeneralize the automaton as an SBA" << std::endl
	    << std::endl


	    << "Automaton simplifications (after translation):"
	    << std::endl
	    << "  -R1q  merge states using direct simulation "
	    << "(use -L for more reduction)"
	    << std::endl
	    << "  -R1t  remove transitions using direct simulation "
	    << "(use -L for more reduction)"
	    << std::endl
	    << "  -R2q  merge states using delayed simulation" << std::endl
	    << "  -R2t  remove transitions using delayed simulation"
	    << std::endl
	    << "  -R3   use SCC to reduce the automata" << std::endl
	    << "  -R3f  clean more acceptance conditions than -R3" << std::endl
	    << "          "
	    << "(prefer -R3 over -R3f if you degeneralize with -D, -DS, or -N)"
	    << std::endl
	    << "  -Rd   display the simulation relation" << std::endl
	    << "  -RD   display the parity game (dot format)" << std::endl
            << "  -Rm   attempt to minimize the automata" << std::endl
	    << std::endl

            << "Automaton conversion:"
            << "  -M    convert into a deterministic minimal monitor "
	    << "(implies -R3 or R3b)" << std::endl
	    << std::endl

	    << "Options for performing emptiness checks:" << std::endl
	    << "  -e[ALGO]  run emptiness check, expect and compute an "
	    << "accepting run" << std::endl
	    << "  -E[ALGO]  run emptiness check, expect no accepting run"
	    << std::endl
	    << "  -C    compute an accepting run (Counterexample) if it exists"
	    << std::endl
	    << "  -CR   compute and replay an accepting run (implies -C)"
	    << std::endl
	    << "  -g    graph the accepting run on the automaton (requires -e)"
	    << std::endl
	    << "  -G    graph the accepting run seen as an automaton "
	    << " (requires -e)" << std::endl
	    << "  -m    try to reduce accepting runs, in a second pass"
	    << std::endl
	    << "Where ALGO should be one of:" << std::endl
	    << "  Cou99(OPTIONS) (the default)" << std::endl
	    << "  CVWY90(OPTIONS)" << std::endl
	    << "  GV04(OPTIONS)" << std::endl
	    << "  SE05(OPTIONS)" << std::endl
	    << "  Tau03(OPTIONS)" << std::endl
	    << "  Tau03_opt(OPTIONS)" << std::endl
	    << std::endl

	    << "If no emptiness check is run, the automaton will be output "
	    << "in dot format" << std::endl << "by default.  This can be "
	    << "changed with the following options." << std::endl
	    << std::endl

	    << "Output options (if no emptiness check):" << std::endl
	    << "  -b    output the automaton in the format of spot"
            << std::endl
            << "  -FC   dump the automaton showing future conditions on states"
	    << std::endl
	    << "  -k    display statistics on the automaton (size and SCCs)"
	    << std::endl
	    << "  -ks   display statistics on the automaton (size only)"
	    << std::endl
	    << "  -K    dump the graph of SCCs in dot format" << std::endl
	    << "  -KV   verbosely dump the graph of SCCs in dot format"
	    << std::endl
	    << "  -N    output the never clain for Spin (implies -D)"
	    << std::endl
	    << "  -NN   output the never clain for Spin, with commented states"
	    << " (implies -D)" << std::endl
	    << "  -O    tell whether the automaton is a safety automaton"
	    << std::endl
	    << "  -t    output automaton in LBTT's format" << std::endl
	    << std::endl

	    << "Miscellaneous options:" << std::endl
	    << "  -0    produce minimal output dedicated to the paper"
	    << std::endl
	    << "  -d    turn on traces during parsing" << std::endl
	    << "  -s    convert to explicit automata, and number states "
	    << "in DFS order" << std::endl
	    << "  -S    convert to explicit automata, and number states "
	    << "in BFS order" << std::endl
            << "  -T    time the different phases of the translation"
	    << std::endl
	    << "  -v    display the BDD variables used by the automaton"
	    << std::endl;
  exit(2);
}

int
main(int argc, char** argv)
{
  int exit_code = 0;

  bool debug_opt = false;
  bool paper_opt = false;
  enum { NoDegen, DegenTBA, DegenSBA } degeneralize_opt = NoDegen;
  enum { TransitionLabeled, StateLabeled } labeling_opt = TransitionLabeled;
  enum { TransFM, TransLaCIM, TransLaCIM_ELTL, TransLaCIM_ELTL_ops, TransTAA }
    translation = TransFM;
  int fm_red = spot::ltl::Reduce_None;
  bool fm_exprop_opt = false;
  bool fm_symb_merge_opt = true;
  bool file_opt = false;
  int output = 0;
  int formula_index = 0;
  const char* echeck_algo = 0;
  spot::emptiness_check_instantiator* echeck_inst = 0;
  enum { NoneDup, BFS, DFS } dupexp = NoneDup;
  bool expect_counter_example = false;
  bool accepting_run = false;
  bool accepting_run_replay = false;
  bool from_file = false;
  bool read_neverclaim = false;
  int reduc_aut = spot::Reduce_None;
  int redopt = spot::ltl::Reduce_None;
  bool scc_filter_all = false;
  bool symbolic_scc_pruning = false;
  bool display_reduce_form = false;
  bool display_rel_sim = false;
  bool display_parity_game = false;
  bool post_branching = false;
  bool fair_loop_approx = false;
  bool graph_run_opt = false;
  bool graph_run_tgba_opt = false;
  bool opt_reduce = false;
  bool opt_minimize = false;
  bool opt_monitor = false;
  bool containment = false;
  bool show_fc = false;
  bool spin_comments = false;
  spot::ltl::environment& env(spot::ltl::default_environment::instance());
  spot::ltl::atomic_prop_set* unobservables = 0;
  spot::tgba_explicit_string* system = 0;
  spot::tgba* product = 0;
  spot::tgba* product_to_free = 0;
  spot::bdd_dict* dict = new spot::bdd_dict();
  spot::timer_map tm;
  bool use_timer = false;

  for (;;)
    {
      if (argc < formula_index + 2)
	syntax(argv[0]);

      ++formula_index;

      if (!strcmp(argv[formula_index], "-0"))
	{
	  paper_opt = true;
	}
      else if (!strcmp(argv[formula_index], "-a"))
	{
	  output = 2;
	}
      else if (!strcmp(argv[formula_index], "-A"))
	{
	  output = 4;
	}
      else if (!strcmp(argv[formula_index], "-b"))
	{
	  output = 7;
	}
      else if (!strcmp(argv[formula_index], "-c"))
	{
	  containment = true;
	  translation = TransTAA;
	}
      else if (!strcmp(argv[formula_index], "-C"))
	{
	  accepting_run = true;
	}
      else if (!strcmp(argv[formula_index], "-CR"))
	{
	  accepting_run = true;
	  accepting_run_replay = true;
	}
      else if (!strcmp(argv[formula_index], "-d"))
	{
	  debug_opt = true;
	}
      else if (!strcmp(argv[formula_index], "-D"))
	{
	  degeneralize_opt = DegenTBA;
	}
      else if (!strcmp(argv[formula_index], "-DS"))
	{
	  degeneralize_opt = DegenSBA;
	}
      else if (!strncmp(argv[formula_index], "-e", 2))
        {
	  echeck_algo = 2 + argv[formula_index];
	  if (!*echeck_algo)
	    echeck_algo = "Cou99";

	  const char* err;
	  echeck_inst =
	    spot::emptiness_check_instantiator::construct(echeck_algo, &err);
	  if (!echeck_inst)
	    {
	      std::cerr << "Failed to parse argument of -e near `"
			<< err <<  "'" << std::endl;
	      exit(2);
	    }
          expect_counter_example = true;
          output = -1;
        }
      else if (!strncmp(argv[formula_index], "-E", 2))
        {
	  const char* echeck_algo = 2 + argv[formula_index];
	  if (!*echeck_algo)
	    echeck_algo = "Cou99";

	  const char* err;
	  echeck_inst =
	    spot::emptiness_check_instantiator::construct(echeck_algo, &err);
	  if (!echeck_inst)
	    {
	      std::cerr << "Failed to parse argument of -e near `"
			<< err <<  "'" << std::endl;
	      exit(2);
	    }
          expect_counter_example = false;
          output = -1;
        }
      else if (!strcmp(argv[formula_index], "-f"))
	{
	  translation = TransFM;
	}
      else if (!strcmp(argv[formula_index], "-fr1"))
	{
	  translation = TransFM;
	  fm_red |= spot::ltl::Reduce_Basics;
	}
      else if (!strcmp(argv[formula_index], "-fr2"))
	{
	  translation = TransFM;
	  fm_red |= spot::ltl::Reduce_Eventuality_And_Universality;
	}
      else if (!strcmp(argv[formula_index], "-fr3"))
	{
	  translation = TransFM;
	  fm_red |= spot::ltl::Reduce_Syntactic_Implications;
	}
      else if (!strcmp(argv[formula_index], "-fr4"))
	{
	  translation = TransFM;
 	  fm_red |= spot::ltl::Reduce_Basics
	    | spot::ltl::Reduce_Eventuality_And_Universality
	    | spot::ltl::Reduce_Syntactic_Implications;
	}
      else if (!strcmp(argv[formula_index], "-fr5"))
	{
	  translation = TransFM;
	  fm_red |= spot::ltl::Reduce_Containment_Checks;
	}
      else if (!strcmp(argv[formula_index], "-fr6"))
	{
	  translation = TransFM;
	  fm_red |= spot::ltl::Reduce_Containment_Checks_Stronger;
	}
      else if (!strcmp(argv[formula_index], "-fr7"))
	{
	  translation = TransFM;
	  fm_red |= spot::ltl::Reduce_All;
	}
      else if (!strcmp(argv[formula_index], "-F"))
	{
	  file_opt = true;
	}
      else if (!strcmp(argv[formula_index], "-FC"))
	{
	  show_fc = true;
	}
      else if (!strcmp(argv[formula_index], "-g"))
	{
	  accepting_run = true;
	  graph_run_opt = true;
	}
      else if (!strcmp(argv[formula_index], "-G"))
	{
	  accepting_run = true;
	  graph_run_tgba_opt = true;
	}
      else if (!strcmp(argv[formula_index], "-k"))
	{
	  output = 9;
	}
      else if (!strcmp(argv[formula_index], "-ks"))
	{
	  output = 12;
	}
      else if (!strcmp(argv[formula_index], "-K"))
	{
	  output = 10;
	}
      else if (!strcmp(argv[formula_index], "-KV"))
	{
	  output = 11;
	}
      else if (!strcmp(argv[formula_index], "-l"))
	{
	  translation = TransLaCIM;
	}
      else if (!strcmp(argv[formula_index], "-le"))
	{
	  /* -lo is documented to imply -le, so do not overwrite it. */
	  if (translation != TransLaCIM_ELTL_ops)
	    translation = TransLaCIM_ELTL;
	}
      else if (!strcmp(argv[formula_index], "-lo"))
	{
	  translation = TransLaCIM_ELTL_ops;
	}
      else if (!strcmp(argv[formula_index], "-L"))
	{
	  fair_loop_approx = true;
	  translation = TransFM;
	}
      else if (!strcmp(argv[formula_index], "-lS"))
	{
	  labeling_opt = StateLabeled;
	}
      else if (!strcmp(argv[formula_index], "-m"))
	{
	  opt_reduce = true;
	}
      else if (!strcmp(argv[formula_index], "-N"))
	{
	  degeneralize_opt = DegenSBA;
	  output = 8;
	}
      else if (!strcmp(argv[formula_index], "-NN"))
	{
	  degeneralize_opt = DegenSBA;
	  output = 8;
	  spin_comments = true;
	}
      else if (!strcmp(argv[formula_index], "-O"))
	{
	  output = 13;
	}
      else if (!strcmp(argv[formula_index], "-p"))
	{
	  post_branching = true;
	  translation = TransFM;
	}
      else if (!strncmp(argv[formula_index], "-P", 2))
	{
	  tm.start("reading -P's argument");

	  spot::tgba_parse_error_list pel;
	  system = spot::tgba_parse(argv[formula_index] + 2,
				    pel, dict, env, env, debug_opt);
	  if (spot::format_tgba_parse_errors(std::cerr,
					     argv[formula_index] + 2, pel))
	    return 2;
	  system->merge_transitions();

	  tm.stop("reading -P's argument");
	}
      else if (!strcmp(argv[formula_index], "-r"))
	{
	  output = 1;
	}
      else if (!strcmp(argv[formula_index], "-r1"))
	{
	  redopt |= spot::ltl::Reduce_Basics;
	}
      else if (!strcmp(argv[formula_index], "-r2"))
	{
	  redopt |= spot::ltl::Reduce_Eventuality_And_Universality;
	}
      else if (!strcmp(argv[formula_index], "-r3"))
	{
	  redopt |= spot::ltl::Reduce_Syntactic_Implications;
	}
      else if (!strcmp(argv[formula_index], "-r4"))
	{
 	  redopt |= spot::ltl::Reduce_Basics
	    | spot::ltl::Reduce_Eventuality_And_Universality
	    | spot::ltl::Reduce_Syntactic_Implications;
	}
      else if (!strcmp(argv[formula_index], "-r5"))
	{
	  redopt |= spot::ltl::Reduce_Containment_Checks;
	}
      else if (!strcmp(argv[formula_index], "-r6"))
	{
	  redopt |= spot::ltl::Reduce_Containment_Checks_Stronger;
	}
      else if (!strcmp(argv[formula_index], "-r7"))
	{
	  redopt |= spot::ltl::Reduce_All;
	}
      else if (!strcmp(argv[formula_index], "-R"))
	{
	  output = 3;
	}
      else if (!strcmp(argv[formula_index], "-R1q"))
	{
	  reduc_aut |= spot::Reduce_quotient_Dir_Sim;
	}
      else if (!strcmp(argv[formula_index], "-R1t"))
	{
	  reduc_aut |= spot::Reduce_transition_Dir_Sim;
	}
      else if (!strcmp(argv[formula_index], "-R2q"))
	{
	  reduc_aut |= spot::Reduce_quotient_Del_Sim;
	}
      else if (!strcmp(argv[formula_index], "-R2t"))
	{
	  reduc_aut |= spot::Reduce_transition_Del_Sim;
	}
      else if (!strcmp(argv[formula_index], "-R3"))
	{
	  reduc_aut |= spot::Reduce_Scc;
	}
      else if (!strcmp(argv[formula_index], "-R3f"))
	{
	  reduc_aut |= spot::Reduce_Scc;
	  scc_filter_all = true;
	}
      else if (!strcmp(argv[formula_index], "-R3b"))
	{
	  symbolic_scc_pruning = true;
	}
      else if (!strcmp(argv[formula_index], "-rd"))
	{
	  display_reduce_form = true;
	}
      else if (!strcmp(argv[formula_index], "-Rd"))
	{
	  display_rel_sim = true;
	}
      else if (!strcmp(argv[formula_index], "-RD"))
	{
	  display_parity_game = true;
	}
      else if (!strcmp(argv[formula_index], "-Rm"))
        {
          opt_minimize = true;
        }
      else if (!strcmp(argv[formula_index], "-M"))
        {
          opt_monitor = true;
        }
      else if (!strcmp(argv[formula_index], "-s"))
	{
	  dupexp = DFS;
	}
      else if (!strcmp(argv[formula_index], "-S"))
	{
	  dupexp = BFS;
	}
      else if (!strcmp(argv[formula_index], "-t"))
	{
	  output = 6;
	}
      else if (!strcmp(argv[formula_index], "-T"))
	{
	  use_timer = true;
	}
      else if (!strcmp(argv[formula_index], "-taa"))
	{
	  translation = TransTAA;
	}
      else if (!strncmp(argv[formula_index], "-U", 2))
	{
	  unobservables = new spot::ltl::atomic_prop_set;
	  translation = TransFM;
	  // Parse -U's argument.
	  const char* tok = strtok(argv[formula_index] + 2, ", \t;");
	  while (tok)
	    {
	      unobservables->insert
		(static_cast<spot::ltl::atomic_prop*>(env.require(tok)));
	      tok = strtok(0, ", \t;");
	    }
	}
      else if (!strcmp(argv[formula_index], "-v"))
	{
	  output = 5;
	}
      else if (!strcmp(argv[formula_index], "-x"))
	{
	  translation = TransFM;
	  fm_exprop_opt = true;
	}
      else if (!strcmp(argv[formula_index], "-X"))
	{
	  from_file = true;
	}
      else if (!strcmp(argv[formula_index], "-XN"))
	{
	  from_file = true;
	  read_neverclaim = true;
	}
      else if (!strcmp(argv[formula_index], "-y"))
	{
	  translation = TransFM;
	  fm_symb_merge_opt = false;
	}
      else
	{
	  break;
	}
    }

  if ((graph_run_opt || graph_run_tgba_opt)
      && (!echeck_inst || !expect_counter_example))
    {
      std::cerr << argv[0] << ": error: -g and -G require -e." << std::endl;
      exit(1);
    }

  std::string input;

  if (file_opt)
    {
      tm.start("reading formula");
      if (strcmp(argv[formula_index], "-"))
	{
	  std::ifstream fin(argv[formula_index]);
	  if (!fin)
	    {
	      std::cerr << "Cannot open " << argv[formula_index] << std::endl;
	      exit(2);
	    }

	  if (!std::getline(fin, input, '\0'))
	    {
	      std::cerr << "Cannot read " << argv[formula_index] << std::endl;
	      exit(2);
	    }
	}
      else
	{
	  std::getline(std::cin, input, '\0');
	}
      tm.stop("reading formula");
    }
  else
    {
      input = argv[formula_index];
    }

  spot::ltl::formula* f = 0;
  if (!from_file) // Reading a formula, not reading an automaton from a file.
    {
      switch (translation)
	{
	case TransFM:
	case TransLaCIM:
	case TransTAA:
	  {
	    spot::ltl::parse_error_list pel;
	    tm.start("parsing formula");
	    f = spot::ltl::parse(input, pel, env, debug_opt);
	    tm.stop("parsing formula");
	    exit_code = spot::ltl::format_parse_errors(std::cerr, input, pel);
	  }
	  break;
	case TransLaCIM_ELTL:
	  {
	    spot::eltl::parse_error_list p;
	    tm.start("parsing formula");
	    f = spot::eltl::parse_string(input, p, env, false);
	    tm.stop("parsing formula");
	    exit_code = spot::eltl::format_parse_errors(std::cerr, p);
	  }
	  break;
	case TransLaCIM_ELTL_ops:
	  {
	    // Call the LTL parser first to handle operators such as
	    // [] or <> and rewrite the output as a string with G or F.
	    // Then prepend definitions of usual LTL operators, and parse
	    // the result again as an ELTL formula.
	    spot::ltl::parse_error_list pel;
	    tm.start("parsing formula");
	    f = spot::ltl::parse(input, pel, env, debug_opt);
	    input = ltl_defs();
	    input += "%";
	    input += spot::ltl::to_string(f, true);
	    f->destroy();
	    spot::eltl::parse_error_list p;
	    f = spot::eltl::parse_string(input, p, env, debug_opt);
	    tm.stop("parsing formula");
	    exit_code = spot::eltl::format_parse_errors(std::cerr, p);
	  }
	  break;
	}
    }
  if (f || from_file)
    {
      spot::tgba_bdd_concrete* concrete = 0;
      spot::tgba* to_free = 0;
      spot::tgba* a = 0;

      if (from_file)
	{
	  spot::tgba_explicit_string* e;
	  if (!read_neverclaim)
	    {
	      spot::tgba_parse_error_list pel;
	      tm.start("parsing automaton");
	      to_free = a = e = spot::tgba_parse(input, pel, dict,
						 env, env, debug_opt);
	      tm.stop("parsing automaton");
	      if (spot::format_tgba_parse_errors(std::cerr, input, pel))
		{
		  delete to_free;
		  delete dict;
		  return 2;
		}
	    }
	  else
	    {
	      spot::neverclaim_parse_error_list pel;
	      tm.start("parsing neverclaim");
	      to_free = a = e = spot::neverclaim_parse(input, pel, dict,
						       env, debug_opt);
	      tm.stop("parsing neverclaim");
	      if (spot::format_neverclaim_parse_errors(std::cerr, input, pel))
		{
		  delete to_free;
		  delete dict;
		  return 2;
		}
	    }
	  e->merge_transitions();
	}
      else
	{
	  if (redopt != spot::ltl::Reduce_None)
	    {
	      tm.start("reducing formula");
	      spot::ltl::formula* t = spot::ltl::reduce(f, redopt);
	      f->destroy();
	      tm.stop("reducing formula");
	      f = t;
	      if (display_reduce_form)
		std::cout << spot::ltl::to_string(f) << std::endl;
	    }

	  tm.start("translating formula");
	  switch (translation)
	    {
	    case TransFM:
	      a = spot::ltl_to_tgba_fm(f, dict, fm_exprop_opt,
				       fm_symb_merge_opt,
				       post_branching,
				       fair_loop_approx,
				       unobservables,
				       fm_red);
	      break;
	    case TransTAA:
	      a = spot::ltl_to_taa(f, dict, containment);
	      break;
	    case TransLaCIM:
	      a = concrete = spot::ltl_to_tgba_lacim(f, dict);
	      break;
	    case TransLaCIM_ELTL:
	    case TransLaCIM_ELTL_ops:
	      a = concrete = spot::eltl_to_tgba_lacim(f, dict);
	      break;
	    }
	  tm.stop("translating formula");
	  to_free = a;
	}

      if (opt_monitor && ((reduc_aut & spot::Reduce_Scc) == 0))
	{
	  if (dynamic_cast<spot::tgba_bdd_concrete*>(a))
	    symbolic_scc_pruning = true;
	  else
	    reduc_aut |= spot::Reduce_Scc;
	}

      if (symbolic_scc_pruning)
        {
	  spot::tgba_bdd_concrete* bc =
	    dynamic_cast<spot::tgba_bdd_concrete*>(a);
	  if (!bc)
	    {
	      std::cerr << ("Error: Automaton is not symbolic: cannot "
			    "prune SCCs symbolically.\n"
			    "       Try -R3 instead of -R3b, or use "
			    "another translation.")
			<< std::endl;
	      exit(2);
	    }
	  else
	    {
	      tm.start("reducing A_f w/ symbolic SCC pruning");
	      if (bc)
		bc->delete_unaccepting_scc();
	      tm.stop("reducing A_f w/ symbolic SCC pruning");
	    }
	}

      // Remove dead SCCs and useless acceptance conditions before
      // degeneralization.
      spot::tgba* aut_scc = 0;
      if (reduc_aut & spot::Reduce_Scc)
	{
	  tm.start("reducing A_f w/ SCC");
	  a = aut_scc = spot::scc_filter(a, scc_filter_all);
	  tm.stop("reducing A_f w/ SCC");
	}

      spot::tgba_tba_proxy* degeneralized = 0;
      spot::tgba_sgba_proxy* state_labeled = 0;

      unsigned int n_acc = a->number_of_acceptance_conditions();
      if (echeck_inst
	  && degeneralize_opt == NoDegen
	  && n_acc > 1
	  && echeck_inst->max_acceptance_conditions() < n_acc)
	degeneralize_opt = DegenTBA;
      if (degeneralize_opt == DegenTBA)
	a = degeneralized = new spot::tgba_tba_proxy(a);
      else if (degeneralize_opt == DegenSBA)
	a = degeneralized = new spot::tgba_sba_proxy(a);
      else if (labeling_opt == StateLabeled)
      {
        a = state_labeled = new spot::tgba_sgba_proxy(a);
      }

      spot::tgba_explicit* minimized = 0;
      if (opt_minimize)
	{
	  tm.start("WDBA-minimization");
	  minimized = minimize(a);
	  tm.stop("WDBA-minimization");
	  tm.start("WDBA-check");
	  // If A is a safety automaton, the WDBA minimization
	  // must be correct.
	  if (is_safety_automaton(a))
	    {
	      a = minimized;
	    }
	  else // We don't know if A is a safety automaton.
	    {
	      if (!f)
		{
		  std::cerr << "Error: Without a formula I cannot make "
			    << "sure that the automaton built with -Rm\n"
			    << "       is correct." << std::endl;
		  exit(2);
		}
	      // Let's make sure that A recognizes the same language
	      // as MINIMIZED.
	      spot::ltl::formula* neg =
		spot::ltl::unop::instance(spot::ltl::unop::Not, f->clone());
	      spot::tgba* n = spot::ltl_to_tgba_fm(neg, dict, fm_exprop_opt,
						   fm_symb_merge_opt,
						   post_branching,
						   fair_loop_approx,
						   unobservables, fm_red);
	      neg->destroy();
	      spot::tgba* nscc = spot::scc_filter(n, true);
	      // If the negation is a safety automaton,
	      // then the minimization is correct.
	      if (is_safety_automaton(n))
		{
		  a = minimized;
		}
	      else
		{
		  spot::tgba* p = new spot::tgba_product(minimized, nscc);
		  spot::emptiness_check* ec = couvreur99(p);
		  spot::emptiness_check_result* res = ec->check();
		  if (!res)
		    {
		      delete ec;
		      delete p;
		      spot::tgba* nm = minimize(nscc);
		      p = new spot::tgba_product(a, nm);
		      ec = couvreur99(p);
		      res = ec->check();
		      if (!res)
			{
			  // Finally, we are now sure that it was safe
			  // to minimize the automaton.
			  a = minimized;
			}
		      delete nm;
		    }
		  delete res;
		  delete ec;
		  delete p;
		}
	      delete nscc;
	      delete n;
	    }
	  tm.stop("WDBA-check");
	}

      if (opt_monitor)
	{
	  tm.start("Monitor minimization");
	  a = minimized = minimize(a, true);