projects / bison.git / blame
| Commit | Line | Data |
|---|---|---|
| 720d742f | 1 | /* Compute look-ahead criteria for bison, |
| aa7815f5 | 2 | Copyright 1984, 1986, 1989, 2000 Free Software Foundation, Inc. |
| 720d742f AD |
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 | |
| 7 | it 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, | |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 14 | GNU 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 | |
| 18 | the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
| 19 | Boston, MA 02111-1307, USA. */ | |
| 20 | ||
| 21 | #ifndef LALR_H_ | |
| 22 | # define LALR_H_ | |
| 23 | ||
| a70083a3 AD |
24 | |
| 25 | /* Import the definition of CORE, SHIFTS and REDUCTIONS. */ | |
| 26 | # include "state.h" | |
| 27 | ||
| 28 | ||
| 720d742f AD |
29 | /* Compute how to make the finite state machine deterministic; find |
| 30 | which rules need lookahead in each state, and which lookahead | |
| 31 | tokens they accept. */ | |
| 32 | ||
| 33 | void lalr PARAMS ((void)); | |
| 34 | ||
| 35 | ||
| 36 | /* lalr() builds these data structures. */ | |
| 37 | ||
| 43591cec | 38 | /* GOTO_MAP, FROM_STATE and TO_STATE -- record each shift transition |
| 720d742f AD |
39 | which accepts a variable (a nonterminal). |
| 40 | ||
| 43591cec AD |
41 | FROM_STATE[T] -- state number which a transition leads from. |
| 42 | TO_STATE[T] -- state number it leads to. | |
| 43 | ||
| 44 | All the transitions that accept a particular variable are grouped | |
| 45 | together and GOTO_MAP[I - NTOKENS] is the index in FROM_STATE and | |
| 46 | TO_STATE of the first of them. */ | |
| 720d742f AD |
47 | |
| 48 | extern short *goto_map; | |
| 49 | extern short *from_state; | |
| 50 | extern short *to_state; | |
| 51 | ||
| 52 | /* CONSISTENT[S] is nonzero if no lookahead is needed to decide what | |
| 53 | to do in state S. */ | |
| 54 | ||
| 55 | extern char *consistent; | |
| 56 | ||
| 57 | ||
| 58 | /* LARULENO is a vector which records the rules that need lookahead in | |
| 59 | various states. The elements of LARULENO that apply to state S are | |
| 60 | those from LOOKAHEADS[S] through LOOKAHEADS[S+1]-1. Each element | |
| 61 | of LARULENO is a rule number. | |
| 62 | ||
| 63 | If LR is the length of LAruleno, then a number from 0 to LR-1 can | |
| 64 | specify both a rule and a state where the rule might be applied. | |
| 65 | */ | |
| 66 | ||
| 67 | extern short *LAruleno; | |
| 68 | ||
| 69 | /* LA is a lr by ntokens matrix of bits. LA[l, i] is 1 if the rule | |
| 70 | LAruleno[l] is applicable in the appropriate state when the next | |
| 71 | token is symbol i. If LA[l, i] and LA[l, j] are both 1 for i != j, | |
| 72 | it is a conflict. */ | |
| 73 | ||
| 74 | extern unsigned *LA; | |
| 75 | ||
| 76 | ||
| 77 | extern int tokensetsize; | |
| 78 | extern short *lookaheads; | |
| 79 | extern short *accessing_symbol; | |
| 80 | extern core **state_table; | |
| 81 | extern shifts **shift_table; | |
| 82 | extern reductions **reduction_table; | |
| 83 | ||
| 84 | ||
| 85 | ||
| 86 | #endif /* !LALR_H_ */ |