X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/f004bf6ac4bdfe0b7dcd554eac8c8899512f9475..eb1b07409f0ccad9970c8a60ded9f2a56d205b9c:/src/lalr.h diff --git a/src/lalr.h b/src/lalr.h index 00137154..3fb2ca2f 100644 --- a/src/lalr.h +++ b/src/lalr.h @@ -1,5 +1,7 @@ -/* Compute look-ahead criteria for bison, - Copyright 1984, 1986, 1989, 2000 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. @@ -15,85 +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> -/* Import the definition of CORE, SHIFTS and REDUCTIONS. */ -# include "state.h" - - -/* Compute how to make the finite state machine deterministic; find - which rules need lookahead in each state, and which lookahead - tokens they accept. */ - -void lalr PARAMS ((void)); - - -/* lalr() builds these data structures. */ - -/* GOTO_MAP, FROM_STATE and TO_STATE -- record each shift transition - which accepts a variable (a nonterminal). +/* Import the definition of RULE_T. */ +# include "gram.h" - FROM_STATE[T] -- state number which a transition leads from. - TO_STATE[T] -- state number it leads to. +/* Import the definition of CORE, TRANSITIONS and REDUCTIONS. */ +# include "state.h" - 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 short *goto_map; -extern short *from_state; -extern short *to_state; +/** Build the LALR(1) automaton. -/* LARULENO is a vector which records the rules that need lookahead in - various states. The elements of LARULENO that apply to state S are - those from LOOKAHEADS[S] through LOOKAHEADS[S+1]-1. Each element - of LARULENO is a rule number. + Compute how to make the finite state machine deterministic; find + which rules need lookahead in each state, and which lookahead + tokens they accept. - If LR is the length of LAruleno, then a number from 0 to LR-1 can - specify both a rule and a state where the rule might be applied. - */ + Builds: + - #goto_map + - #from_state + - #to_state +*/ +void lalr (void); -extern short *LAruleno; +/** + * 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, <tt>old_to_new[i]</tt> 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); -/* LA is a lr by ntokens matrix of bits. LA[l, i] is 1 if the rule - LAruleno[l] is applicable in the appropriate state when the next - token is symbol i. If LA[l, i] and LA[l, j] are both 1 for i != j, - it is a conflict. */ -extern unsigned *LA; +/** Release the information related to lookahead tokens. + Can be performed once the action tables are computed. */ +void lalr_free (void); -/* A structure decorating a state, with additional information. */ -typedef struct state_s -{ - /* A state. */ - core *state; - /* Its accessing symbol. */ - short accessing_symbol; +typedef size_t goto_number; +# define GOTO_NUMBER_MAXIMUM ((goto_number) -1) - shifts *shift_table; - reductions *reduction_table; +/** Index into #from_state and #to_state. - /* Nonzero if no lookahead is needed to decide what to do in state - S. */ - char consistent; + 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; - short lookaheads; -} state_t; +/** State number which a transition leads from. */ +extern state_number *from_state; -/* All the decorated states, indexed by the state number. Warning: - there is a state_TABLE in LR0.c, but it is different and static. - */ -extern state_t *state_table; +/** State number it leads to. */ +extern state_number *to_state; -extern int tokensetsize; -/* The number of lookaheads. */ -extern size_t nlookaheads; #endif /* !LALR_H_ */