X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/1c303b00fe3a479021cef5ee48e33d5a65b9d720..eb1b07409f0ccad9970c8a60ded9f2a56d205b9c:/src/lalr.h diff --git a/src/lalr.h b/src/lalr.h index c0ca461c..3fb2ca2f 100644 --- a/src/lalr.h +++ b/src/lalr.h @@ -1,5 +1,7 @@ -/* Compute look-ahead criteria for bison, - Copyright (C) 1984, 1986, 1989, 2000, 2002 Free Software Foundation, Inc. +/* Compute lookahead criteria for bison, + + Copyright (C) 1984, 1986, 1989, 2000, 2002, 2004, 2006, 2007 Free Software + Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. @@ -15,51 +17,69 @@ 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. */ + the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, + Boston, MA 02110-1301, USA. */ #ifndef LALR_H_ # define LALR_H_ -# include "bitset.h" -# include "bitsetv.h" +# include +# include + +/* Import the definition of RULE_T. */ +# include "gram.h" /* Import the definition of CORE, TRANSITIONS and REDUCTIONS. */ # include "state.h" -/* Import the definition of RULE_T. */ -# include "gram.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); -void lalr PARAMS ((void)); +/** + * 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); -/* Release the information related to lookaheads. Can be performed - once the action tables are computed. */ -void lalr_free PARAMS ((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. */ +extern goto_number *goto_map; -typedef short goto_number_t; -# define GOTO_NUMBER_MAX ((goto_number_t) SHRT_MAX) +/** State number which a transition leads from. */ +extern state_number *from_state; -extern goto_number_t *goto_map; -extern state_number_t *from_state; -extern state_number_t *to_state; +/** State number it leads to. */ +extern state_number *to_state; #endif /* !LALR_H_ */