1 /* Subroutines for bison 2 3 Copyright (C) 1984, 1989, 2000, 2001, 2002 Free Software 4 Foundation, Inc. 5 6 This file is part of Bison, the GNU Compiler Compiler. 7 8 Bison is free software; you can redistribute it and/or modify it 9 under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 2, or (at your option) 11 any later version. 12 13 Bison is distributed in the hope that it will be useful, but 14 WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with Bison; see the file COPYING. If not, write to the Free 20 Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 21 02110-1301, USA. */ 22 23 #ifndef CLOSURE_H_ 24 # define CLOSURE_H_ 25 26 # include "gram.h" 27 28 /* Allocates the itemset and ruleset vectors, and precomputes useful 29 data so that closure can be called. n is the number of elements to 30 allocate for itemset. */ 31 32 void new_closure (unsigned int n); 33 34 35 /* Given the kernel (aka core) of a state (a vector of item numbers 36 ITEMS, of length N), set up RULESET and ITEMSET to indicate what 37 rules could be run and which items could be accepted when those 38 items are the active ones. 39 40 RULESET contains a bit for each rule. CLOSURE sets the bits for 41 all rules which could potentially describe the next input to be 42 read. 43 44 ITEMSET is a vector of item numbers; NITEMSET is its size 45 (actually, points to just beyond the end of the part of it that is 46 significant). CLOSURE places there the indices of all items which 47 represent units of input that could arrive next. */ 48 49 void closure (item_number *items, size_t n); 50 51 52 /* Frees ITEMSET, RULESET and internal data. */ 53 54 void free_closure (void); 55 56 extern item_number *itemset; 57 extern size_t nritemset; 58 59 #endif /* !CLOSURE_H_ */ 60
