-/* 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.
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"
+# 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"
-void lalr PARAMS ((void));
+/** Build the LALR(1) automaton.
-/* lalr() builds these data structures. */
+ Compute how to make the finite state machine deterministic; find
+ which rules need lookahead in each state, and which lookahead
+ tokens they accept.
-/* GOTO_MAP, FROM_STATE and TO_STATE -- record each shift transition
- which accepts a variable (a nonterminal).
+ Builds:
+ - #goto_map
+ - #from_state
+ - #to_state
+*/
+void lalr (void);
- FROM_STATE[T] -- state number which a transition leads from.
- TO_STATE[T] -- state number it leads to.
+/**
+ * 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);
- 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;
+/** Release the information related to lookahead tokens.
+
+ Can be performed once the action tables are computed. */
+void lalr_free (void);
-/* 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.
- */
+typedef size_t goto_number;
+# define GOTO_NUMBER_MAXIMUM ((goto_number) -1)
-extern rule_t **LArule;
+/** Index into #from_state and #to_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. */
+ 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 bitsetv LA;
+/** State number which a transition leads from. */
+extern state_number *from_state;
+/** State number it leads to. */
+extern state_number *to_state;
-/* All the states, indexed by the state number. */
-extern state_t **states;
#endif /* !LALR_H_ */
projects / bison.git / blobdiff