X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/b78d8c23dacf2298a96013206bfd48763e3cb54a..eb1b07409f0ccad9970c8a60ded9f2a56d205b9c:/src/lalr.h

diff --git a/src/lalr.h b/src/lalr.h
index 7912a089..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.
 
@@ -15,8 +17,8 @@
 
    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_
@@ -30,35 +32,53 @@
 /* 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, <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.  */
-
-typedef short 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;