src/closure.h

   1 /* Subroutines for bison
   2    Copyright 1984, 1989, 2000 Free Software Foundation, Inc.
   3
   4    This file is part of Bison, the GNU Compiler Compiler.
   5
   6    Bison is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2, or (at your option)
   9    any later version.
  10
  11    Bison is distributed in the hope that it will be useful, but
  12    WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with Bison; see the file COPYING.  If not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  19    02111-1307, USA.  */
  20
  21 #ifndef CLOSURE_H_
  22 # define CLOSURE_H_
  23
  24 /* Subroutines of file LR0.c. */
  25
  26 /* Allocates the itemset and ruleset vectors, and precomputes useful
  27    data so that closure can be called.  n is the number of elements to
  28    allocate for itemset.  */
  29
  30 void new_closure PARAMS ((int n));
  31
  32
  33 /* Given a vector of item numbers ITEMS, of length N, set up ruleset
  34    and itemset to indicate what rules could be run and which items
  35    could be accepted when those items are the active ones.
  36
  37    ruleset contains a bit for each rule.  closure sets the bits for
  38    all rules which could potentially describe the next input to be
  39    read.
  40
  41    itemset is a vector of item numbers; itemsetend points to just
  42    beyond the end of the part of it that is significant.  closure
  43    places there the indices of all items which represent units of
  44    input that could arrive next.  */
  45
  46 void closure PARAMS ((short *items, int n));
  47
  48
  49 /* Frees itemset, ruleset and internal data.  */
  50
  51 void free_closure PARAMS ((void));
  52
  53 extern short *itemset;
  54 extern short *itemsetend;
  55
  56 #endif /* !CLOSURE_H_ */