# Exercising Bison Grammar Reduction. -*- Autotest -*-
-# Copyright 2001 Free Software Foundation, Inc.
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2, or (at your option)
-# any later version.
+# Copyright (C) 2001-2002, 2007-2012 Free Software Foundation, Inc.
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
-
+#
# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
-# 02111-1307, USA.
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
AT_BANNER([[Grammar Reduction.]])
AT_DATA([[input.y]],
[[%verbose
-%output="input.c"
+%output "input.c"
%token useless1
%token useless2
exp: useful;
]])
-AT_CHECK([[bison input.y]], 0, [],
-[[input.y contains 9 useless nonterminals
-]])
+AT_BISON_CHECK([[input.y]])
AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' input.output]], 0,
-[[Useless nonterminals:
+[[Terminals unused in grammar
useless1
useless2
useless3
AT_DATA([[input.y]],
[[%verbose
-%output="input.c"
+%output "input.c"
%nterm useless1
%nterm useless2
exp: useful;
]])
-AT_CHECK([[bison input.y]], 0, [],
-[[input.y contains 9 useless nonterminals
+AT_BISON_CHECK([[input.y]], 0, [],
+[[input.y: warning: 9 nonterminals useless in grammar
+input.y:4.8-15: warning: nonterminal useless in grammar: useless1
+input.y:5.8-15: warning: nonterminal useless in grammar: useless2
+input.y:6.8-15: warning: nonterminal useless in grammar: useless3
+input.y:7.8-15: warning: nonterminal useless in grammar: useless4
+input.y:8.8-15: warning: nonterminal useless in grammar: useless5
+input.y:9.8-15: warning: nonterminal useless in grammar: useless6
+input.y:10.8-15: warning: nonterminal useless in grammar: useless7
+input.y:11.8-15: warning: nonterminal useless in grammar: useless8
+input.y:12.8-15: warning: nonterminal useless in grammar: useless9
+]])
+
+AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' input.output]], 0,
+[[Nonterminals useless in grammar
+ useless1
+ useless2
+ useless3
+ useless4
+ useless5
+ useless6
+ useless7
+ useless8
+ useless9
+]])
+
+AT_CLEANUP
+
+
+
+## --------------- ##
+## Useless Rules. ##
+## --------------- ##
+
+AT_SETUP([Useless Rules])
+
+AT_KEYWORDS([report])
+
+AT_DATA([[input.y]],
+[[%verbose
+%output "input.c"
+%token useful
+%%
+exp: useful;
+useless1: '1';
+useless2: '2';
+useless3: '3';
+useless4: '4';
+useless5: '5';
+useless6: '6';
+useless7: '7';
+useless8: '8';
+useless9: '9';
+]])
+
+AT_BISON_CHECK([[input.y]], 0, [],
+[[input.y: warning: 9 nonterminals useless in grammar
+input.y: warning: 9 rules useless in grammar
+input.y:6.1-8: warning: nonterminal useless in grammar: useless1
+input.y:7.1-8: warning: nonterminal useless in grammar: useless2
+input.y:8.1-8: warning: nonterminal useless in grammar: useless3
+input.y:9.1-8: warning: nonterminal useless in grammar: useless4
+input.y:10.1-8: warning: nonterminal useless in grammar: useless5
+input.y:11.1-8: warning: nonterminal useless in grammar: useless6
+input.y:12.1-8: warning: nonterminal useless in grammar: useless7
+input.y:13.1-8: warning: nonterminal useless in grammar: useless8
+input.y:14.1-8: warning: nonterminal useless in grammar: useless9
+input.y:6.11-13: warning: rule useless in grammar: useless1: '1'
+input.y:7.11-13: warning: rule useless in grammar: useless2: '2'
+input.y:8.11-13: warning: rule useless in grammar: useless3: '3'
+input.y:9.11-13: warning: rule useless in grammar: useless4: '4'
+input.y:10.11-13: warning: rule useless in grammar: useless5: '5'
+input.y:11.11-13: warning: rule useless in grammar: useless6: '6'
+input.y:12.11-13: warning: rule useless in grammar: useless7: '7'
+input.y:13.11-13: warning: rule useless in grammar: useless8: '8'
+input.y:14.11-13: warning: rule useless in grammar: useless9: '9'
]])
AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' input.output]], 0,
-[[Useless nonterminals:
+[[Nonterminals useless in grammar
useless1
useless2
useless3
useless7
useless8
useless9
+Terminals unused in grammar
+ '1'
+ '2'
+ '3'
+ '4'
+ '5'
+ '6'
+ '7'
+ '8'
+ '9'
+Rules useless in grammar
+ 2 useless1: '1'
+ 3 useless2: '2'
+ 4 useless3: '3'
+ 5 useless4: '4'
+ 6 useless5: '5'
+ 7 useless6: '6'
+ 8 useless7: '7'
+ 9 useless8: '8'
+ 10 useless9: '9'
+]])
+
+AT_CLEANUP
+
+
+
+## ------------------- ##
+## Reduced Automaton. ##
+## ------------------- ##
+
+# Check that the automaton is that as the for the grammar reduced by
+# hand.
+
+AT_SETUP([Reduced Automaton])
+
+AT_KEYWORDS([report])
+
+# The non reduced grammar.
+# ------------------------
+AT_DATA([[not-reduced.y]],
+[[/* A useless token. */
+%token useless_token
+/* A useful one. */
+%token useful
+%verbose
+%output "not-reduced.c"
+
+%%
+
+exp: useful { /* A useful action. */ }
+ | non_productive { /* A non productive action. */ }
+ ;
+
+not_reachable: useful { /* A not reachable action. */ }
+ ;
+
+non_productive: non_productive useless_token
+ { /* Another non productive action. */ }
+ ;
+%%
+]])
+
+AT_BISON_CHECK([[not-reduced.y]], 0, [],
+[[not-reduced.y: warning: 2 nonterminals useless in grammar
+not-reduced.y: warning: 3 rules useless in grammar
+not-reduced.y:14.1-13: warning: nonterminal useless in grammar: not_reachable
+not-reduced.y:11.6-19: warning: nonterminal useless in grammar: non_productive
+not-reduced.y:11.6-57: warning: rule useless in grammar: exp: non_productive
+not-reduced.y:14.16-56: warning: rule useless in grammar: not_reachable: useful
+not-reduced.y:17.17-18.63: warning: rule useless in grammar: non_productive: non_productive useless_token
+]])
+
+AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' not-reduced.output]], 0,
+[[Nonterminals useless in grammar
+ not_reachable
+ non_productive
+Terminals unused in grammar
+ useless_token
+Rules useless in grammar
+ 2 exp: non_productive
+ 3 not_reachable: useful
+ 4 non_productive: non_productive useless_token
+]])
+
+# The reduced grammar.
+# --------------------
+AT_DATA([[reduced.y]],
+[[/* A useless token. */
+%token useless_token
+/* A useful one. */
+%token useful
+%verbose
+%output "reduced.c"
+
+%%
+
+exp: useful { /* A useful action. */ }
+// | non_productive { /* A non productive action. */ } */
+ ;
+
+//not_reachable: useful { /* A not reachable action. */ }
+// ;
+
+//non_productive: non_productive useless_token
+// { /* Another non productive action. */ }
+// ;
+%%
+]])
+
+AT_BISON_CHECK([[reduced.y]])
+
+# Comparing the parsers.
+cp reduced.c expout
+AT_CHECK([sed 's/not-reduced/reduced/g' not-reduced.c], 0, [expout])
+
+AT_CLEANUP
+
+
+
+## ------------------- ##
+## Underivable Rules. ##
+## ------------------- ##
+
+AT_SETUP([Underivable Rules])
+
+AT_KEYWORDS([report])
+
+AT_DATA([[input.y]],
+[[%verbose
+%output "input.c"
+%token useful
+%%
+exp: useful | underivable;
+underivable: indirection;
+indirection: underivable;
+]])
+
+AT_BISON_CHECK([[input.y]], 0, [],
+[[input.y: warning: 2 nonterminals useless in grammar
+input.y: warning: 3 rules useless in grammar
+input.y:5.15-25: warning: nonterminal useless in grammar: underivable
+input.y:6.14-24: warning: nonterminal useless in grammar: indirection
+input.y:5.15-25: warning: rule useless in grammar: exp: underivable
+input.y:6.14-24: warning: rule useless in grammar: underivable: indirection
+input.y:7.14-24: warning: rule useless in grammar: indirection: underivable
+]])
+
+AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' input.output]], 0,
+[[Nonterminals useless in grammar
+ underivable
+ indirection
+Rules useless in grammar
+ 2 exp: underivable
+ 3 underivable: indirection
+ 4 indirection: underivable
+]])
+
+AT_CLEANUP
+
+
+
+## ---------------- ##
+## Empty Language. ##
+## ---------------- ##
+
+AT_SETUP([Empty Language])
+
+AT_DATA([[input.y]],
+[[%output "input.c"
+%%
+exp: exp;
+]])
+
+AT_BISON_CHECK([[input.y]], 1, [],
+[[input.y: warning: 2 nonterminals useless in grammar
+input.y: warning: 2 rules useless in grammar
+input.y:3.1-3: fatal error: start symbol exp does not derive any sentence
]])
AT_CLEANUP
+
+
+
+## ----------------- ##
+## %define lr.type. ##
+## ----------------- ##
+
+# AT_TEST_LR_TYPE(DESCRIPTION,
+# DECLS, GRAMMAR, INPUT,
+# BISON-STDERR, TABLES,
+# [OTHER-CHECKS],
+# [PARSER-EXIT-VALUE],
+# [PARSER-STDOUT], [PARSER-STDERR])
+# -------------------------------------------------
+m4_define([AT_TEST_LR_TYPE],
+[
+AT_TEST_TABLES_AND_PARSE([[no %define lr.type: ]$1],
+ [[LALR]], [[]],
+ [$2], m4_shiftn(2, $@))
+AT_TEST_TABLES_AND_PARSE([[%define lr.type lalr: ]$1],
+ [[LALR]], [[]],
+ [[%define lr.type lalr
+]$2],
+ m4_shiftn(2, $@))
+AT_TEST_TABLES_AND_PARSE([[%define lr.type ielr: ]$1],
+ [[IELR]], [[]],
+ [[%define lr.type ielr
+]$2],
+ m4_shiftn(2, $@))
+AT_TEST_TABLES_AND_PARSE([[%define lr.type canonical-lr: ]$1],
+ [[canonical LR]], [[]],
+ [[%define lr.type canonical-lr
+]$2],
+ m4_shiftn(2, $@))
+])
+
+AT_TEST_LR_TYPE([[Single State Split]],
+[[%left 'a'
+// Conflict resolution renders state 12 unreachable for canonical LR(1). We
+// keep it so that the paser table diff is easier to code.
+%define lr.keep-unreachable-states]],
+[[
+S: 'a' A 'a' /* rule 1 */
+ | 'b' A 'b' /* rule 2 */
+ | 'c' c /* rule 3 */
+ ;
+
+/* A conflict should appear after the first 'a' in rules 4 and 5 but only after
+ having shifted the first 'a' in rule 1. However, when LALR(1) merging is
+ chosen, the state containing that conflict is reused after having seen the
+ first 'b' in rule 2 and then the first 'a' in rules 4 and 5. In both cases,
+ because of the merged state, if the next token is an 'a', the %left forces a
+ reduction action with rule 5. In the latter case, only a shift is actually
+ grammatically correct. Thus, the parser would report a syntax error for the
+ grammatically correct sentence "baab" because it would encounter a syntax
+ error after that incorrect reduction.
+
+ Despite not being LALR(1), Menhir version 20070322 suffers from this problem
+ as well. It uses David Pager's weak compatibility test for merging states.
+ Bison and Menhir accept non-LR(1) grammars with conflict resolution. Pager
+ designed his algorithm only for LR(1) grammars. */
+A: 'a' 'a' /* rule 4 */
+ | 'a' /* rule 5 */
+ ;
+
+/* Rule 3, rule 6, and rule 7 ensure that Bison does not report rule 4 as
+ useless after conflict resolution. This proves that, even though LALR(1)
+ generates incorrect parser tables sometimes, Bison will not necessarily
+ produce any warning to help the user realize it. */
+c: 'a' 'b' /* rule 6 */
+ | A /* rule 7 */
+ ;
+]],
+
+dnl INPUT
+[['b', 'a', 'a', 'b']],
+
+dnl BISON-STDERR
+[],
+
+dnl TABLES
+[[state 0
+
+ 0 $accept: . S $end
+ 1 S: . 'a' A 'a'
+ 2 | . 'b' A 'b'
+ 3 | . 'c' c
+
+ 'a' shift, and go to state 1
+ 'b' shift, and go to state 2
+ 'c' shift, and go to state 3
+
+ S go to state 4
+
+
+state 1
+
+ 1 S: 'a' . A 'a'
+ 4 A: . 'a' 'a'
+ 5 | . 'a'
+
+ 'a' shift, and go to state 5
+
+ A go to state 6
+
+
+state 2
+
+ 2 S: 'b' . A 'b'
+ 4 A: . 'a' 'a'
+ 5 | . 'a'
+
+ 'a' shift, and go to state ]AT_COND_CASE([[LALR]], [[5]], [[16]])[
+
+ A go to state 7
+
+
+state 3
+
+ 3 S: 'c' . c
+ 4 A: . 'a' 'a'
+ 5 | . 'a'
+ 6 c: . 'a' 'b'
+ 7 | . A
+
+ 'a' shift, and go to state 8
+
+ A go to state 9
+ c go to state 10
+
+
+state 4
+
+ 0 $accept: S . $end
+
+ $end shift, and go to state 11
+
+
+state 5
+
+ 4 A: 'a' . 'a'
+ 5 | 'a' . ]AT_COND_CASE([[LALR]], [[['a', 'b']]], [[['a']]])[
+
+ ]AT_COND_CASE([[canonical LR]], [['a']],
+ [[$default]])[ reduce using rule 5 (A)
+
+ Conflict between rule 5 and token 'a' resolved as reduce (%left 'a').
+
+
+state 6
+
+ 1 S: 'a' A . 'a'
+
+ 'a' shift, and go to state 13
+
+
+state 7
+
+ 2 S: 'b' A . 'b'
+
+ 'b' shift, and go to state 14
+
+
+state 8
+
+ 4 A: 'a' . 'a'
+ 5 | 'a' . [$end]
+ 6 c: 'a' . 'b'
+
+ 'a' shift, and go to state ]AT_COND_CASE([[canonical LR]], [[17]],
+ [[12]])[
+ 'b' shift, and go to state 15
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 5 (A)
+
+
+state 9
+
+ 7 c: A .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 7 (c)
+
+
+state 10
+
+ 3 S: 'c' c .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 3 (S)
+
+
+state 11
+
+ 0 $accept: S $end .
+
+ $default accept
+
+
+state 12
+
+ 4 A: 'a' 'a' .]AT_COND_CASE([[canonical LR]], [[ ['a']]])[
+
+ ]AT_COND_CASE([[canonical LR]], [['a']],
+ [[$default]])[ reduce using rule 4 (A)
+
+
+state 13
+
+ 1 S: 'a' A 'a' .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 1 (S)
+
+
+state 14
+
+ 2 S: 'b' A 'b' .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 2 (S)
+
+
+state 15
+
+ 6 c: 'a' 'b' .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 6 (c)]AT_COND_CASE([[LALR]],
+ [[]], [[
+
+
+state 16
+
+ 4 A: 'a' . 'a'
+ 5 | 'a' . ['b']
+
+ 'a' shift, and go to state ]AT_COND_CASE([[canonical LR]], [[18]],
+ [[12]])[
+
+ ]AT_COND_CASE([[canonical LR]], [['b']],
+ [[$default]])[ reduce using rule 5 (A)]AT_COND_CASE([[canonical LR]], [[
+
+
+state 17
+
+ 4 A: 'a' 'a' . [$end]
+
+ $end reduce using rule 4 (A)
+
+
+state 18
+
+ 4 A: 'a' 'a' . ['b']
+
+ 'b' reduce using rule 4 (A)]])])[
+]],
+
+dnl OTHER-CHECKS
+[],
+
+dnl PARSER-EXIT-VALUE, PARSER-STDOUT, PARSER-STDERR
+[AT_COND_CASE([[LALR]], [[1]], [[0]])],
+[],
+[AT_COND_CASE([[LALR]],
+[[syntax error
+]])])
+
+AT_TEST_LR_TYPE([[Lane Split]],
+[[%left 'a'
+// Conflict resolution renders state 16 unreachable for canonical LR(1). We
+// keep it so that the paser table diff is easier to code.
+%define lr.keep-unreachable-states]],
+[[
+/* Similar to the last test case set but two states must be split. */
+S: 'a' A 'a' /* rule 1 */
+ | 'b' A 'b' /* rule 2 */
+ | 'c' c /* rule 3 */
+ ;
+
+A: 'a' 'a' 'a' /* rule 4 */
+ | 'a' 'a' /* rule 5 */
+ ;
+
+c: 'a' 'a' 'b' /* rule 6 */
+ | A /* rule 7 */
+ ;
+]],
+
+dnl INPUT
+[['b', 'a', 'a', 'a', 'b']],
+
+dnl BISON-STDERR
+[],
+
+dnl TABLES
+[[state 0
+
+ 0 $accept: . S $end
+ 1 S: . 'a' A 'a'
+ 2 | . 'b' A 'b'
+ 3 | . 'c' c
+
+ 'a' shift, and go to state 1
+ 'b' shift, and go to state 2
+ 'c' shift, and go to state 3
+
+ S go to state 4
+
+
+state 1
+
+ 1 S: 'a' . A 'a'
+ 4 A: . 'a' 'a' 'a'
+ 5 | . 'a' 'a'
+
+ 'a' shift, and go to state 5
+
+ A go to state 6
+
+
+state 2
+
+ 2 S: 'b' . A 'b'
+ 4 A: . 'a' 'a' 'a'
+ 5 | . 'a' 'a'
+
+ 'a' shift, and go to state ]AT_COND_CASE([[LALR]], [[5]], [[18]])[
+
+ A go to state 7
+
+
+state 3
+
+ 3 S: 'c' . c
+ 4 A: . 'a' 'a' 'a'
+ 5 | . 'a' 'a'
+ 6 c: . 'a' 'a' 'b'
+ 7 | . A
+
+ 'a' shift, and go to state 8
+
+ A go to state 9
+ c go to state 10
+
+
+state 4
+
+ 0 $accept: S . $end
+
+ $end shift, and go to state 11
+
+
+state 5
+
+ 4 A: 'a' . 'a' 'a'
+ 5 | 'a' . 'a'
+
+ 'a' shift, and go to state 12
+
+
+state 6
+
+ 1 S: 'a' A . 'a'
+
+ 'a' shift, and go to state 13
+
+
+state 7
+
+ 2 S: 'b' A . 'b'
+
+ 'b' shift, and go to state 14
+
+
+state 8
+
+ 4 A: 'a' . 'a' 'a'
+ 5 | 'a' . 'a'
+ 6 c: 'a' . 'a' 'b'
+
+ 'a' shift, and go to state 15
+
+
+state 9
+
+ 7 c: A .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 7 (c)
+
+
+state 10
+
+ 3 S: 'c' c .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 3 (S)
+
+
+state 11
+
+ 0 $accept: S $end .
+
+ $default accept
+
+
+state 12
+
+ 4 A: 'a' 'a' . 'a'
+ 5 | 'a' 'a' . ]AT_COND_CASE([[LALR]], [[['a', 'b']]], [[['a']]])[
+
+ ]AT_COND_CASE([[canonical LR]], [['a']],
+ [[$default]])[ reduce using rule 5 (A)
+
+ Conflict between rule 5 and token 'a' resolved as reduce (%left 'a').
+
+
+state 13
+
+ 1 S: 'a' A 'a' .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 1 (S)
+
+
+state 14
+
+ 2 S: 'b' A 'b' .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 2 (S)
+
+
+state 15
+
+ 4 A: 'a' 'a' . 'a'
+ 5 | 'a' 'a' . [$end]
+ 6 c: 'a' 'a' . 'b'
+
+ 'a' shift, and go to state ]AT_COND_CASE([[canonical LR]], [[19]],
+ [[16]])[
+ 'b' shift, and go to state 17
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 5 (A)
+
+
+state 16
+
+ 4 A: 'a' 'a' 'a' .]AT_COND_CASE([[canonical LR]], [[ ['a']]])[
+
+ ]AT_COND_CASE([[canonical LR]], [['a']],
+ [[$default]])[ reduce using rule 4 (A)
+
+
+state 17
+
+ 6 c: 'a' 'a' 'b' .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 6 (c)]AT_COND_CASE([[LALR]],
+ [[]], [[
+
+
+state 18
+
+ 4 A: 'a' . 'a' 'a'
+ 5 | 'a' . 'a'
+
+ 'a' shift, and go to state ]AT_COND_CASE([[canonical LR]], [[20]],
+ [[19]])[
+
+
+state 19]AT_COND_CASE([[canonical LR]], [[
+
+ 4 A: 'a' 'a' 'a' .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 4 (A)
+
+
+state 20]])[
+
+ 4 A: 'a' 'a' . 'a'
+ 5 | 'a' 'a' . ['b']
+
+ 'a' shift, and go to state ]AT_COND_CASE([[canonical LR]], [[21]],
+ [[16]])[
+
+ ]AT_COND_CASE([[canonical LR]], [['b']],
+ [[$default]])[ reduce using rule 5 (A)]AT_COND_CASE([[canonical LR]], [[
+
+
+state 21
+
+ 4 A: 'a' 'a' 'a' .]AT_COND_CASE([[canonical LR]], [[ ['b']]])[
+
+ ]AT_COND_CASE([[canonical LR]], [['b']],
+ [[$default]])[ reduce using rule 4 (A)]])])[
+]],
+
+dnl OTHER-CHECKS
+[],
+
+dnl PARSER-EXIT-VALUE, PARSER-STDOUT, PARSER-STDERR
+[AT_COND_CASE([[LALR]], [[1]], [[0]])],
+[],
+[AT_COND_CASE([[LALR]],
+[[syntax error
+]])])
+
+AT_TEST_LR_TYPE([[Complex Lane Split]],
+[[%left 'a'
+// Conflict resolution renders state 16 unreachable for canonical LR(1). We
+// keep it so that the paser table diff is easier to code.
+%define lr.keep-unreachable-states]],
+[[
+/* Similar to the last test case set but forseeing the S/R conflict from the
+ first state that must be split is becoming difficult. Imagine if B were
+ even more complex. Imagine if A had other RHS's ending in other
+ nonterminals. */
+S: 'a' A 'a'
+ | 'b' A 'b'
+ | 'c' c
+ ;
+A: 'a' 'a' B
+ ;
+B: 'a'
+ | %prec 'a'
+ ;
+c: 'a' 'a' 'b'
+ | A
+ ;
+]],
+
+dnl INPUT
+[['b', 'a', 'a', 'a', 'b']],
+
+dnl BISON-STDERR
+[],
+
+dnl TABLES
+[[state 0
+
+ 0 $accept: . S $end
+ 1 S: . 'a' A 'a'
+ 2 | . 'b' A 'b'
+ 3 | . 'c' c
+
+ 'a' shift, and go to state 1
+ 'b' shift, and go to state 2
+ 'c' shift, and go to state 3
+
+ S go to state 4
+
+
+state 1
+
+ 1 S: 'a' . A 'a'
+ 4 A: . 'a' 'a' B
+
+ 'a' shift, and go to state 5
+
+ A go to state 6
+
+
+state 2
+
+ 2 S: 'b' . A 'b'
+ 4 A: . 'a' 'a' B
+
+ 'a' shift, and go to state ]AT_COND_CASE([[LALR]], [[5]], [[19]])[
+
+ A go to state 7
+
+
+state 3
+
+ 3 S: 'c' . c
+ 4 A: . 'a' 'a' B
+ 7 c: . 'a' 'a' 'b'
+ 8 | . A
+
+ 'a' shift, and go to state 8
+
+ A go to state 9
+ c go to state 10
+
+
+state 4
+
+ 0 $accept: S . $end
+
+ $end shift, and go to state 11
+
+
+state 5
+
+ 4 A: 'a' . 'a' B
+
+ 'a' shift, and go to state 12
+
+
+state 6
+
+ 1 S: 'a' A . 'a'
+
+ 'a' shift, and go to state 13
+
+
+state 7
+
+ 2 S: 'b' A . 'b'
+
+ 'b' shift, and go to state 14
+
+
+state 8
+
+ 4 A: 'a' . 'a' B
+ 7 c: 'a' . 'a' 'b'
+
+ 'a' shift, and go to state 15
+
+
+state 9
+
+ 8 c: A .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 8 (c)
+
+
+state 10
+
+ 3 S: 'c' c .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 3 (S)
+
+
+state 11
+
+ 0 $accept: S $end .
+
+ $default accept
+
+
+state 12
+
+ 4 A: 'a' 'a' . B
+ 5 B: . 'a'
+ 6 | . ]AT_COND_CASE([[LALR]], [[['a', 'b']]], [[['a']]])[
+
+ ]AT_COND_CASE([[canonical LR]], [['a']],
+ [[$default]])[ reduce using rule 6 (B)
+
+ B go to state 17
+
+ Conflict between rule 6 and token 'a' resolved as reduce (%left 'a').
+
+
+state 13
+
+ 1 S: 'a' A 'a' .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 1 (S)
+
+
+state 14
+
+ 2 S: 'b' A 'b' .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 2 (S)
+
+
+state 15
+
+ 4 A: 'a' 'a' . B
+ 5 B: . 'a'
+ 6 | . [$end]
+ 7 c: 'a' 'a' . 'b'
+
+ 'a' shift, and go to state ]AT_COND_CASE([[canonical LR]], [[20]],
+ [[16]])[
+ 'b' shift, and go to state 18
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 6 (B)
+
+ B go to state ]AT_COND_CASE([[canonical LR]], [[21]], [[17]])[
+
+
+state 16
+
+ 5 B: 'a' .]AT_COND_CASE([[canonical LR]], [[ ['a']]])[
+
+ ]AT_COND_CASE([[canonical LR]], [['a']],
+ [[$default]])[ reduce using rule 5 (B)
+
+
+state 17
+
+ 4 A: 'a' 'a' B .]AT_COND_CASE([[canonical LR]], [[ ['a']]])[
+
+ ]AT_COND_CASE([[canonical LR]], [['a']],
+ [[$default]])[ reduce using rule 4 (A)
+
+
+state 18
+
+ 7 c: 'a' 'a' 'b' .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 7 (c)]AT_COND_CASE([[LALR]], [], [[
+
+
+state 19
+
+ 4 A: 'a' . 'a' B
+
+ 'a' shift, and go to state ]AT_COND_CASE([[canonical LR]], [[22]],
+ [[20]])[
+
+
+state 20]AT_COND_CASE([[canonical LR]], [[
+
+ 5 B: 'a' . [$end]
+
+ $end reduce using rule 5 (B)
+
+
+state 21
+
+ 4 A: 'a' 'a' B . [$end]
+
+ $end reduce using rule 4 (A)
+
+
+state 22]])[
+
+ 4 A: 'a' 'a' . B
+ 5 B: . 'a'
+ 6 | . ['b']
+
+ 'a' shift, and go to state ]AT_COND_CASE([[canonical LR]], [[23]],
+ [[16]])[
+
+ ]AT_COND_CASE([[canonical LR]], [['b']],
+ [[$default]])[ reduce using rule 6 (B)
+
+ B go to state ]AT_COND_CASE([[canonical LR]], [[24
+
+
+state 23
+
+ 5 B: 'a' . ['b']
+
+ 'b' reduce using rule 5 (B)
+
+
+state 24
+
+ 4 A: 'a' 'a' B . ['b']
+
+ 'b' reduce using rule 4 (A)]], [[17]])])[
+]],
+
+dnl OTHER-CHECKS
+[],
+
+dnl PARSER-EXIT-VALUE, PARSER-STDOUT, PARSER-STDERR
+[AT_COND_CASE([[LALR]], [[1]], [[0]])],
+[],
+[AT_COND_CASE([[LALR]],
+[[syntax error
+]])])
+
+AT_TEST_LR_TYPE([[Split During Added Lookahead Propagation]],
+[[%define lr.keep-unreachable-states]],
+[[
+/* The partial state chart diagram below is for LALR(1). State 0 is the start
+ state. States are iterated for successor construction in numerical order.
+ Transitions are downwards.
+
+ State 13 has a R/R conflict that cannot be predicted by Bison's LR(1)
+ algorithm using annotations alone. That is, when state 11's successor on
+ 'd' is merged with state 5 (which is originally just state 1's successor on
+ 'd'), state 5's successor on 'e' must then be changed because the resulting
+ lookaheads that propagate to it now make it incompatible with state 8's
+ successor on 'e'. In other words, state 13 must be split to avoid the
+ conflict.
+
+ 0
+ / | \
+ a / c| \ b
+ 1 3 2
+ | | |
+ d| |c | d
+ | 11 |
+ | | |
+ \ /d |
+ 5 8
+ \ |
+ e \ / e
+ 13
+ R/R
+
+ This grammar is designed carefully to make sure that, despite Bison's LR(1)
+ algorithm's bread-first iteration of transitions to reconstruct states,
+ state 11's successors are constructed after state 5's and state 8's.
+ Otherwise (for example, if you remove the first 'c' in each of rules 6 and
+ 7), state 5's successor on 'e' would never be merged with state 8's, so the
+ split of the resulting state 13 would never need to be performed. */
+S: 'a' A 'f'
+ | 'a' B
+ | 'b' A 'f'
+ | 'b' B 'g'
+ | 'b' 'd'
+ | 'c' 'c' A 'g'
+ | 'c' 'c' B
+ ;
+A: 'd' 'e' ;
+B: 'd' 'e' ;
+]],
+
+dnl INPUT
+[['b', 'd', 'e', 'g']],
+
+dnl BISON-STDERR
+[AT_COND_CASE([[LALR]],
+[[input.y: conflicts: 1 reduce/reduce
+]], [])],
+
+dnl TABLES
+[[state 0
+
+ 0 $accept: . S $end
+ 1 S: . 'a' A 'f'
+ 2 | . 'a' B
+ 3 | . 'b' A 'f'
+ 4 | . 'b' B 'g'
+ 5 | . 'b' 'd'
+ 6 | . 'c' 'c' A 'g'
+ 7 | . 'c' 'c' B
+
+ 'a' shift, and go to state 1
+ 'b' shift, and go to state 2
+ 'c' shift, and go to state 3
+
+ S go to state 4
+
+
+state 1
+
+ 1 S: 'a' . A 'f'
+ 2 | 'a' . B
+ 8 A: . 'd' 'e'
+ 9 B: . 'd' 'e'
+
+ 'd' shift, and go to state 5
+
+ A go to state 6
+ B go to state 7
+
+
+state 2
+
+ 3 S: 'b' . A 'f'
+ 4 | 'b' . B 'g'
+ 5 | 'b' . 'd'
+ 8 A: . 'd' 'e'
+ 9 B: . 'd' 'e'
+
+ 'd' shift, and go to state 8
+
+ A go to state 9
+ B go to state 10
+
+
+state 3
+
+ 6 S: 'c' . 'c' A 'g'
+ 7 | 'c' . 'c' B
+
+ 'c' shift, and go to state 11
+
+
+state 4
+
+ 0 $accept: S . $end
+
+ $end shift, and go to state 12
+
+
+state 5
+
+ 8 A: 'd' . 'e'
+ 9 B: 'd' . 'e'
+
+ 'e' shift, and go to state ]AT_COND_CASE([[LALR]], [[13]],
+ [[canonical LR]], [[13]],
+ [[20]])[
+
+
+state 6
+
+ 1 S: 'a' A . 'f'
+
+ 'f' shift, and go to state 14
+
+
+state 7
+
+ 2 S: 'a' B .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 2 (S)
+
+
+state 8
+
+ 5 S: 'b' 'd' . [$end]
+ 8 A: 'd' . 'e'
+ 9 B: 'd' . 'e'
+
+ 'e' shift, and go to state ]AT_COND_CASE([[canonical LR]], [[20]],
+ [[13]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 5 (S)
+
+
+state 9
+
+ 3 S: 'b' A . 'f'
+
+ 'f' shift, and go to state 15
+
+
+state 10
+
+ 4 S: 'b' B . 'g'
+
+ 'g' shift, and go to state 16
+
+
+state 11
+
+ 6 S: 'c' 'c' . A 'g'
+ 7 | 'c' 'c' . B
+ 8 A: . 'd' 'e'
+ 9 B: . 'd' 'e'
+
+ 'd' shift, and go to state ]AT_COND_CASE([[canonical LR]], [[21]],
+ [[5]])[
+
+ A go to state 17
+ B go to state 18
+
+
+state 12
+
+ 0 $accept: S $end .
+
+ $default accept]AT_COND_CASE([[LALR]], [[
+
+
+state 13
+
+ 8 A: 'd' 'e' . ['f', 'g']
+ 9 B: 'd' 'e' . [$end, 'g']
+
+ $end reduce using rule 9 (B)
+ 'g' reduce using rule 8 (A)
+ 'g' [reduce using rule 9 (B)]
+ $default reduce using rule 8 (A)]], [[
+
+
+state 13
+
+ 8 A: 'd' 'e' . ['f']
+ 9 B: 'd' 'e' . ]AT_COND_CASE([[canonical LR]], [[[$end]]], [[['g']]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [['g' ]])[ reduce using rule 9 (B)
+ ]AT_COND_CASE([[canonical LR]], [['f' ]],
+ [[$default]])[ reduce using rule 8 (A)]])[
+
+
+state 14
+
+ 1 S: 'a' A 'f' .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 1 (S)
+
+
+state 15
+
+ 3 S: 'b' A 'f' .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 3 (S)
+
+
+state 16
+
+ 4 S: 'b' B 'g' .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 4 (S)
+
+
+state 17
+
+ 6 S: 'c' 'c' A . 'g'
+
+ 'g' shift, and go to state 19
+
+
+state 18
+
+ 7 S: 'c' 'c' B .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 7 (S)
+
+
+state 19
+
+ 6 S: 'c' 'c' A 'g' .]AT_COND_CASE([[canonical LR]], [[ [$end]]])[
+
+ ]AT_COND_CASE([[canonical LR]], [[$end]],
+ [[$default]])[ reduce using rule 6 (S)]AT_COND_CASE([[LALR]],
+ [[]], [[
+
+
+state 20]AT_COND_CASE([[canonical LR]], [[
+
+ 8 A: 'd' 'e' . ['f']
+ 9 B: 'd' 'e' . ['g']
+
+ 'f' reduce using rule 8 (A)
+ 'g' reduce using rule 9 (B)
+
+
+state 21
+
+ 8 A: 'd' . 'e'
+ 9 B: 'd' . 'e'
+
+ 'e' shift, and go to state 22
+
+
+state 22
+
+ 8 A: 'd' 'e' . ['g']
+ 9 B: 'd' 'e' . [$end]
+
+ $end reduce using rule 9 (B)
+ 'g' reduce using rule 8 (A)]], [[
+
+ 8 A: 'd' 'e' . ['f', 'g']
+ 9 B: 'd' 'e' . [$end]
+
+ $end reduce using rule 9 (B)
+ $default reduce using rule 8 (A)]])])[
+]],
+
+dnl OTHER-CHECKS
+[],
+
+dnl PARSER-EXIT-VALUE, PARSER-STDOUT, PARSER-STDERR
+[AT_COND_CASE([[LALR]], [[1]], [[0]])],
+[],
+[AT_COND_CASE([[LALR]],
+[[syntax error
+]])])
+
+
+
+## ------------------------------- ##
+## %define lr.default-reductions. ##
+## ------------------------------- ##
+
+# AT_TEST_LR_DEFAULT_REDUCTIONS(GRAMMAR, INPUT, TABLES)
+# -----------------------------------------------------
+m4_define([AT_TEST_LR_DEFAULT_REDUCTIONS],
+[
+AT_TEST_TABLES_AND_PARSE([[no %define lr.default-reductions]],
+ [[most]], [[]],
+ [[]],
+ [$1], [$2], [[]], [$3])
+AT_TEST_TABLES_AND_PARSE([[%define lr.default-reductions most]],
+ [[most]], [[]],
+ [[%define lr.default-reductions most]],
+ [$1], [$2], [[]], [$3])
+AT_TEST_TABLES_AND_PARSE([[%define lr.default-reductions consistent]],
+ [[consistent]], [[]],
+ [[%define lr.default-reductions consistent]],
+ [$1], [$2], [[]], [$3])
+AT_TEST_TABLES_AND_PARSE([[%define lr.default-reductions accepting]],
+ [[accepting]], [[]],
+ [[%define lr.default-reductions accepting]],
+ [$1], [$2], [[]], [$3])
+])
+
+AT_TEST_LR_DEFAULT_REDUCTIONS([[
+/* The start state is consistent and has a shift on 'a' and no reductions.
+ After pushing the b below, enter an inconsistent state that has a shift and
+ one reduction with one lookahead. */
+start:
+ a b
+ | a b 'a'
+ | a c 'b'
+ ;
+
+/* After shifting this 'a', enter a consistent state that has no shift and 1
+ reduction with multiple lookaheads. */
+a: 'a' ;
+
+/* After the previous reduction, enter an inconsistent state that has no shift
+ and multiple reductions. The first reduction has more lookaheads than the
+ second, so the first should always be preferred as the default reduction if
+ enabled. The second reduction has one lookahead. */
+b: ;
+c: ;
+]],
+dnl Visit each state mentioned above.
+[['a', 'a']],
+[[state 0
+
+ 0 $accept: . start $end
+ 1 start: . a b
+ 2 | . a b 'a'
+ 3 | . a c 'b'
+ 4 a: . 'a'
+
+ 'a' shift, and go to state 1
+
+ start go to state 2
+ a go to state 3
+
+
+state 1
+
+ 4 a: 'a' .]AT_COND_CASE([[accepting]], [[ [$end, 'a', 'b']
+
+ $end reduce using rule 4 (a)
+ 'a' reduce using rule 4 (a)
+ 'b' reduce using rule 4 (a)]], [[
+
+ $default reduce using rule 4 (a)]])[
+
+
+state 2
+
+ 0 $accept: start . $end
+
+ $end shift, and go to state 4
+
+
+state 3
+
+ 1 start: a . b
+ 2 | a . b 'a'
+ 3 | a . c 'b'
+ 5 b: . [$end, 'a']
+ 6 c: . ['b']]AT_COND_CASE([[most]], [[
+
+ 'b' reduce using rule 6 (c)
+ $default reduce using rule 5 (b)]], [[
+
+ $end reduce using rule 5 (b)
+ 'a' reduce using rule 5 (b)
+ 'b' reduce using rule 6 (c)]])[
+
+ b go to state 5
+ c go to state 6
+
+
+state 4
+
+ 0 $accept: start $end .
+
+ $default accept
+
+
+state 5
+
+ 1 start: a b . [$end]
+ 2 | a b . 'a'
+
+ 'a' shift, and go to state 7
+
+ ]AT_COND_CASE([[most]], [[$default]],
+ [[$end]])[ reduce using rule 1 (start)
+
+
+state 6
+
+ 3 start: a c . 'b'
+
+ 'b' shift, and go to state 8
+
+
+state 7
+
+ 2 start: a b 'a' .]AT_COND_CASE([[accepting]], [[ [$end]
+
+ $end reduce using rule 2 (start)]], [[
+
+ $default reduce using rule 2 (start)]])[
+
+
+state 8
+
+ 3 start: a c 'b' .]AT_COND_CASE([[accepting]], [[ [$end]
+
+ $end reduce using rule 3 (start)]], [[
+
+ $default reduce using rule 3 (start)]])[
+]])
projects / bison.git / blobdiff