X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/779e7ceb9395424c2cf90d43c75302ababc8ee72..9ca7f077a0a5ecdd00c5945c7a7bd3cf46e23c13:/src/lalr.h diff --git a/src/lalr.h b/src/lalr.h index ce10edd0..c65c9b48 100644 --- a/src/lalr.h +++ b/src/lalr.h @@ -1,24 +1,22 @@ -/* Compute look-ahead criteria for bison, +/* Compute lookahead criteria for bison, - Copyright (C) 1984, 1986, 1989, 2000, 2002, 2004 Free Software + Copyright (C) 1984, 1986, 1989, 2000, 2002, 2004, 2006, 2007 Free Software Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. - Bison is free software; you can redistribute it and/or modify + This program 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, or (at your option) - any later version. + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. - Bison is distributed in the hope that it will be useful, + This program 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 Bison; see the file COPYING. If not, write to - the Free Software Foundation, Inc., 59 Temple Place - Suite 330, - Boston, MA 02111-1307, USA. */ + along with this program. If not, see . */ #ifndef LALR_H_ # define LALR_H_ @@ -32,35 +30,53 @@ /* Import the definition of CORE, TRANSITIONS and REDUCTIONS. */ # include "state.h" -/* Compute how to make the finite state machine deterministic; find + +/** Build the LALR(1) automaton. + + Compute how to make the finite state machine deterministic; find which rules need lookahead in each state, and which lookahead - tokens they accept. */ + tokens they accept. + Builds: + - #goto_map + - #from_state + - #to_state +*/ void lalr (void); -/* Release the information related to lookaheads. Can be performed - once the action tables are computed. */ +/** + * Update state numbers recorded in #goto_map, #from_state, and #to_state such + * that: + * - \c nstates_old is the old number of states. + * - Where \c i is the old state number, old_to_new[i] is either: + * - \c nstates_old if state \c i is removed because it is unreachable. + * Thus, remove all goto entries involving this state. + * - The new state number. + */ +void lalr_update_state_numbers (state_number old_to_new[], + state_number nstates_old); -void lalr_free (void); +/** Release the information related to lookahead tokens. + + Can be performed once the action tables are computed. */ +void lalr_free (void); -/* lalr() builds these data structures. */ -/* GOTO_MAP, FROM_STATE and TO_STATE -- record each shift transition - which accepts a variable (a nonterminal). +typedef size_t goto_number; +# define GOTO_NUMBER_MAXIMUM ((goto_number) -1) - FROM_STATE[T] -- state number which a transition leads from. - TO_STATE[T] -- state number it leads to. +/** Index into #from_state and #to_state. All the transitions that accept a particular variable are grouped together and GOTO_MAP[I - NTOKENS] is the index in FROM_STATE and TO_STATE of the first of them. */ - -typedef short int goto_number; -# define GOTO_NUMBER_MAXIMUM SHRT_MAX - extern goto_number *goto_map; + +/** State number which a transition leads from. */ extern state_number *from_state; + +/** State number it leads to. */ extern state_number *to_state;