X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/d57650a5ff3d9d1202f6d04de1a10e32cee85499..c53b6848897960bc783afdbc230e1a247977d63d:/src/lalr.h

diff --git a/src/lalr.h b/src/lalr.h
index 82719d40..f4833157 100644
--- a/src/lalr.h
+++ b/src/lalr.h
@@ -1,77 +1,106 @@
-/* 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,
+   2009-2013 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 <http://www.gnu.org/licenses/>.  */
 
 #ifndef LALR_H_
 # define LALR_H_
 
-#include "bitset.h"
-#include "bitsetv.h"
-
-/* Import the definition of CORE, SHIFTS and REDUCTIONS. */
-# include "state.h"
+# include <bitset.h>
+# include <bitsetv.h>
 
 /* Import the definition of RULE_T. */
 # include "gram.h"
 
-/* Compute how to make the finite state machine deterministic; find
-   which rules need lookahead in each state, and which lookahead
-   tokens they accept.  */
+/* Import the definition of CORE, TRANSITIONS and REDUCTIONS. */
+# include "state.h"
+
+
+/** Build the LALR(1) automaton.
+
+   Find which rules need lookahead in each state, and which lookahead
+   tokens they accept.
 
-void lalr PARAMS ((void));
+   Also builds:
+     - #goto_map
+     - #from_state
+     - #to_state
+     - #goto_follows
+*/
+void lalr (void);
 
+/**
+ * Set #nLA and allocate all reduction lookahead sets.  Normally invoked by
+ * #lalr.
+ */
+void initialize_LA (void);
 
-/* lalr() builds these data structures. */
+/**
+ * Build only:
+ *   - #goto_map
+ *   - #from_state
+ *   - #to_state
+ * Normally invoked by #lalr.
+ */
+void set_goto_map (void);
 
-/* GOTO_MAP, FROM_STATE and TO_STATE -- record each shift transition
-   which accepts a variable (a nonterminal).
+/**
+ * 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);
 
-   FROM_STATE[T] -- state number which a transition leads from.
-   TO_STATE[T] -- state number it leads to.
+
+/** Release the information related to lookahead tokens.
+
+   Can be performed once the action tables are computed.  */
+void lalr_free (void);
+
+typedef size_t goto_number;
+# define GOTO_NUMBER_MAXIMUM ((goto_number) -1)
+
+/** 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;
 
-extern short *goto_map;
-extern state_number_t *from_state;
-extern state_number_t *to_state;
-
-/* LARULE is a vector which records the rules that need lookahead in
-   various states.  The elements of LARULE that apply to state S are
-   those from LOOKAHEADS[S] through LOOKAHEADS[S+1]-1.
-
-   If LR is the length of LArule, then a number from 0 to LR-1 can
-   specify both a rule and a state where the rule might be applied.
-   */
+/** The size of #from_state and #to_state.  */
+extern goto_number ngotos;
 
-extern rule_t **LArule;
+/** State number which a transition leads from.  */
+extern state_number *from_state;
 
-/* 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.  */
+/** State number it leads to.  */
+extern state_number *to_state;
 
-extern bitsetv LA;
+/** Map a state/symbol pair into its numeric representation.  */
+goto_number map_goto (state_number s0, symbol_number sym);
 
+/* goto_follows[i] is the set of tokens following goto i.  */
+extern bitsetv goto_follows;
 
-/* All the states, indexed by the state number.  */
-extern state_t **states;
 
 #endif /* !LALR_H_ */