src/lssi.h

   1 /* Lookahead sensitive state item searches for counterexample generation
   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 LSSI_H
  21 # define LSSI_H
  22
  23 # include "state-item.h"
  24
  25 /*
  26   All state-item graph nodes should also include a precise follow set (follow_L).
  27   However, ignoring follow_L saves a lot of memory and is a pretty good approximation.
  28   These functions exist to enforce restrictions caused by follow_L sets.
  29  */
  30
  31 /*
  32  * find shortest lookahead-sensitive path of state-items to target such that
  33  * next_sym is in the follow_L set of target in that position.
  34 */
  35 state_item_list shortest_path_from_start (state_item_number target,
  36                                           symbol_number next_sym);
  37
  38 /**
  39  * Determine if the given terminal is in the given symbol set or can begin
  40  * a nonterminal in the given symbol set.
  41  */
  42 bool intersect_symbol (symbol_number sym, bitset syms);
  43
  44 /**
  45  * Determine if any symbol in ts is in syms
  46  * or can begin with a nonterminal in syms.
  47  */
  48 bool intersect (bitset ts, bitset syms);
  49
  50 /**
  51  * Compute a set of sequences of state-items that can make production steps
  52  * to this state-item such that the resulting possible lookahead symbols are
  53  * as given.
  54  */
  55 state_item_list lssi_reverse_production (const state_item *si, bitset lookahead);
  56
  57 #endif /* LSSI_H */