#define PROG_NAME "grr_reducer"
#define PROG_DESC "reduce and reorder a SELVA grammar"
#define PROG_VERS "1.0"

/* Copyright © 2004 by the State University of Campinas (UNICAMP). */
/* See the copyright, authorship, and warranty notice at end of file. */
/* Last edited on 2024-12-21 11:47:41 by stolfi */

/* TO DO:
  Remove unreachable symbols and rules? (Need axiom).
*/

#define PROG_HELP \
  "  " PROG_NAME " < GRAMMAR.gex > GRAMMAR.red"

#define PROG_INFO \
  "NAME\n" \
  "  " PROG_NAME " - " PROG_DESC "\n" \
  "\n" \
  "SYNOPSIS\n" \
  PROG_HELP "\n" \
  "\n" \
  "DESCRIPTION\n" \
  "  ???\n" \
  "\n" \
  "AUTHORS\n" \
  "  Created 2004-12-08 by Lucien Fantin and Jorge Stolfi at IC-UNICAMP."

#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <stdio.h>

#include <filefmt.h>
#include <fget.h>
#include <nget.h>
#include <vec.h>

#include <grr_grammar.h>
#include <grr_nonempty.h>
#include <grr_nondead.h>
#include <grr_toposort.h>
#include <grr_bypass.h>

/* PROTOTYPES */
  
int main(int argc, char **argv);
void grr_arg_error(char *msg);

/* IMPLEMENTATIONS */

int main(int argc, char **argv)
  {
    /* Get command line argument */
    if (argc != 1) { grr_arg_error("bad args"); }
    
    /* Read expanded grammar. */
    Grammar_t *G1 = grr_read_Grammar(stdin);
    /* grr_write_Grammar(stderr, G1); */

    /* Remove empty rules: */
    Grammar_t *G2 = grr_remove_empty_rules(G1);
    grr_free_grammar(G1);

    /* Remove invalid symbols: */
    Grammar_t *G3 = grr_remove_invalid_symbols(G2);
    grr_free_grammar(G2);
    
    /* Simplify grammar by substituting internal symbols with unary rules: */
    Grammar_t *G4 = grr_remove_superfluous_symbols(G3);
    grr_free_grammar(G3);

    /* Renumber symbols so that unary rules are increasing: */
    Grammar_t *G5 = grr_sort_symbols(G4);
    grr_free_grammar(G4);
    
    /* Output numerically-coded grammar: */
    grr_write_Grammar(stdout, G5);

    return 0;
  }
  
void grr_arg_error(char *msg)
  {
    fprintf(stderr, "** %s: %s", PROG_NAME, msg);
    fprintf(stderr, "usage: %s\n", PROG_HELP);
    exit(1);
  }