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| 1 /* Compute lookahead criteria for bison, |
| 2 |
| 3 Copyright (C) 1984, 1986, 1989, 2000, 2002, 2004, 2006, 2007 Free Software |
| 4 Foundation, Inc. |
| 5 |
| 6 This file is part of Bison, the GNU Compiler Compiler. |
| 7 |
| 8 This program is free software: you can redistribute it and/or modify |
| 9 it under the terms of the GNU General Public License as published by |
| 10 the Free Software Foundation, either version 3 of the License, or |
| 11 (at your option) any later version. |
| 12 |
| 13 This program is distributed in the hope that it will be useful, |
| 14 but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 GNU General Public License for more details. |
| 17 |
| 18 You should have received a copy of the GNU General Public License |
| 19 along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 20 |
| 21 #ifndef LALR_H_ |
| 22 # define LALR_H_ |
| 23 |
| 24 # include <bitset.h> |
| 25 # include <bitsetv.h> |
| 26 |
| 27 /* Import the definition of RULE_T. */ |
| 28 # include "gram.h" |
| 29 |
| 30 /* Import the definition of CORE, TRANSITIONS and REDUCTIONS. */ |
| 31 # include "state.h" |
| 32 |
| 33 |
| 34 /** Build the LALR(1) automaton. |
| 35 |
| 36 Compute how to make the finite state machine deterministic; find |
| 37 which rules need lookahead in each state, and which lookahead |
| 38 tokens they accept. |
| 39 |
| 40 Builds: |
| 41 - #goto_map |
| 42 - #from_state |
| 43 - #to_state |
| 44 */ |
| 45 void lalr (void); |
| 46 |
| 47 /** |
| 48 * Update state numbers recorded in #goto_map, #from_state, and #to_state such |
| 49 * that: |
| 50 * - \c nstates_old is the old number of states. |
| 51 * - Where \c i is the old state number, <tt>old_to_new[i]</tt> is either: |
| 52 * - \c nstates_old if state \c i is removed because it is unreachable. |
| 53 * Thus, remove all goto entries involving this state. |
| 54 * - The new state number. |
| 55 */ |
| 56 void lalr_update_state_numbers (state_number old_to_new[], |
| 57 state_number nstates_old); |
| 58 |
| 59 |
| 60 /** Release the information related to lookahead tokens. |
| 61 |
| 62 Can be performed once the action tables are computed. */ |
| 63 void lalr_free (void); |
| 64 |
| 65 |
| 66 typedef size_t goto_number; |
| 67 # define GOTO_NUMBER_MAXIMUM ((goto_number) -1) |
| 68 |
| 69 /** Index into #from_state and #to_state. |
| 70 |
| 71 All the transitions that accept a particular variable are grouped |
| 72 together and GOTO_MAP[I - NTOKENS] is the index in FROM_STATE and |
| 73 TO_STATE of the first of them. */ |
| 74 extern goto_number *goto_map; |
| 75 |
| 76 /** State number which a transition leads from. */ |
| 77 extern state_number *from_state; |
| 78 |
| 79 /** State number it leads to. */ |
| 80 extern state_number *to_state; |
| 81 |
| 82 |
| 83 #endif /* !LALR_H_ */ |
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