Simplify last patch slightly.

[bison.git] / src / lalr.h

diff --git a/src/lalr.h b/src/lalr.h
index cd50046bf35c2883e01dcdcbd9fe9936834c7d7e..c65c9b48803ad79d079d2c0cb8f11ffaabf0e8af 100644 (file)
--- 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.
 
    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
    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
    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_
 
 #ifndef LALR_H_
 # define LALR_H_


@@ -32,35 +30,53 @@
 /* Import the definition of CORE, TRANSITIONS and REDUCTIONS. */
 # include "state.h"
 
 /* Import the definition of CORE, TRANSITIONS and REDUCTIONS. */
 # include "state.h"
 

-/* Compute how to make the finite state machine deterministic; find
-   which rules need look-ahead in each state, and which look-ahead
-   tokens they accept.  */

 
 

+/** 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.
+
+   Builds:
+   - #goto_map
+   - #from_state
+   - #to_state
+*/

 void lalr (void);
 
 void lalr (void);
 

-/* Release the information related to look-ahead tokens.  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, <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);

 
 

-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.  */
 
    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;
 extern goto_number *goto_map;

+
+/** State number which a transition leads from. */

 extern state_number *from_state;
 extern state_number *from_state;

+
+/** State number it leads to.  */

 extern state_number *to_state;
 
 
 extern state_number *to_state;