src/derivation.h

   1 /* Counterexample derivation trees
   2
   3    Copyright (C) 2020-2021 Free Software Foundation, Inc.
   4
   5    This file is part of Bison, the GNU Compiler Compiler.
   6
   7    This program is free software: you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation, either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  19
  20 #ifndef DERIVATION_H
  21 # define DERIVATION_H
  22
  23 # include <gl_linked_list.h>
  24 # include <gl_xlist.h>
  25
  26 # include "gram.h"
  27
  28 /* Derivations are trees of symbols such that each nonterminal's
  29    children are symbols that produce that nonterminal if they are
  30    relevant to the counterexample.  The leaves of a derivation form a
  31    counterexample when printed.  */
  32
  33 typedef gl_list_t derivation_list;
  34 typedef struct derivation derivation;
  35
  36 static inline derivation_list derivation_list_new (void)
  37 {
  38   return gl_list_create_empty (GL_LINKED_LIST, NULL, NULL, NULL, true);
  39 }
  40
  41 static inline bool
  42 derivation_list_next (gl_list_iterator_t *it, derivation **d)
  43 {
  44   const void *p = NULL;
  45   bool res = gl_list_iterator_next (it, &p, NULL);
  46   if (res)
  47     *d = (derivation *) p;
  48   else
  49     gl_list_iterator_free (it);
  50   return res;
  51 }
  52
  53 void derivation_list_append (derivation_list dl, derivation *d);
  54 void derivation_list_prepend (derivation_list dl, derivation *d);
  55 void derivation_list_free (derivation_list dl);
  56
  57 // rule_num is the number of the rule SYM -> CHILDREN.
  58 derivation *
  59 derivation_new (symbol_number sym, derivation_list children,
  60                 const rule *r);
  61
  62 static inline derivation *derivation_new_leaf (symbol_number sym)
  63 {
  64   return derivation_new (sym, NULL, NULL);
  65 }
  66
  67 // Number of symbols.
  68 size_t derivation_size (const derivation *deriv);
  69 void derivation_print (const derivation *deriv, FILE *out, const char *prefix);
  70 void derivation_print_leaves (const derivation *deriv, FILE *out);
  71 void derivation_free (derivation *deriv);
  72 void derivation_retain (derivation *deriv);
  73
  74 // A derivation denoting the position of the dot.
  75 derivation *derivation_dot (void);
  76
  77 #endif /* DERIVATION_H */