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Implement %define lr.default_rules.
Its value describes the states that are permitted to contain default rules: "all", "consistent", or "accepting". * src/reader.c (reader): Default lr.default_rules to "all". Check for a valid lr.default_rules value. * src/lalr.c (state_lookahead_tokens_count): If lr.default_rules is "accepting", then only mark the accepting state as consistent. (initialize_LA): Tell state_lookahead_tokens_count whether lr.default_rules is "accepting". * src/tables.c (action_row): If lr.default_rules is not "all", then disable default rules in inconsistent states. * src/print.c (print_reductions): Use this opportunity to perform some assertions about whether lr.default_rules was obeyed correctly. * tests/local.at (AT_TEST_TABLES_AND_PARSE): New macro that helps with checking the parser tables for a grammar. * tests/input.at (%define lr.default_rules invalid values): New test group. * tests/reduce.at (AT_TEST_LR_DEFAULT_RULES): New macro using AT_TEST_TABLES_AND_PARSE. (`no %define lr.default_rules'): New test group generated by AT_TEST_LR_DEFAULT_RULES. (`%define lr.default_rules "all"'): Likewise. (`%define lr.default_rules "consistent"'): Likewise. (`%define lr.default_rules "accepting"'): Likewise.
This commit is contained in:
Joel E. Denny
147
tests/reduce.at
147
tests/reduce.at
@@ -1,5 +1,6 @@
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# Exercising Bison Grammar Reduction. -*- Autotest -*-
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# Copyright (C) 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
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# Copyright (C) 2001, 2002, 2007, 2008, 2009 Free Software Foundation,
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# Inc.
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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@@ -355,3 +356,147 @@ input.y:3.1-3: fatal error: start symbol exp does not derive any sentence
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]])
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AT_CLEANUP
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## -------------------------- ##
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## %define lr.default_rules. ##
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## -------------------------- ##
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# AT_TEST_LR_DEFAULT_RULES(GRAMMAR, INPUT, TABLES)
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# ------------------------------------------------
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m4_define([AT_TEST_LR_DEFAULT_RULES],
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[
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AT_TEST_TABLES_AND_PARSE([[no %define lr.default_rules]],
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[[all]], [[]],
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[[]],
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[$1], [$2], [[]], [$3])
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AT_TEST_TABLES_AND_PARSE([[%define lr.default_rules "all"]],
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[[all]], [[]],
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[[%define lr.default_rules "all"]],
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[$1], [$2], [[]], [$3])
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AT_TEST_TABLES_AND_PARSE([[%define lr.default_rules "consistent"]],
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[[consistent]], [[]],
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[[%define lr.default_rules "consistent"]],
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[$1], [$2], [[]], [$3])
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AT_TEST_TABLES_AND_PARSE([[%define lr.default_rules "accepting"]],
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[[accepting]], [[]],
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[[%define lr.default_rules "accepting"]],
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[$1], [$2], [[]], [$3])
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])
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AT_TEST_LR_DEFAULT_RULES([[
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/* The start state is consistent and has a shift on 'a' and no reductions.
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After pushing the b below, enter an inconsistent state that has a shift and
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one reduction with one lookahead. */
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start:
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a b
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| a b 'a'
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| a c 'b'
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;
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/* After shifting this 'a', enter a consistent state that has no shift and 1
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reduction with multiple lookaheads. */
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a: 'a' ;
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/* After the previous reduction, enter an inconsistent state that has no shift
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and multiple reductions. The first reduction has more lookaheads than the
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second, so the first should always be preferred as the default rule if
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enabled. The second reduction has one lookahead. */
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b: ;
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c: ;
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]],
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dnl Visit each state mentioned above.
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[['a', 'a']],
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[[state 0
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0 $accept: . start $end
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1 start: . a b
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2 | . a b 'a'
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3 | . a c 'b'
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4 a: . 'a'
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'a' shift, and go to state 1
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start go to state 2
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a go to state 3
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state 1
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4 a: 'a' .]AT_COND_CASE([[accepting]], [[ [$end, 'a', 'b']
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$end reduce using rule 4 (a)
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'a' reduce using rule 4 (a)
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'b' reduce using rule 4 (a)]], [[
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$default reduce using rule 4 (a)]])[
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state 2
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0 $accept: start . $end
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$end shift, and go to state 4
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state 3
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1 start: a . b
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2 | a . b 'a'
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3 | a . c 'b'
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5 b: . [$end, 'a']
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6 c: . ['b']]AT_COND_CASE([[all]], [[
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'b' reduce using rule 6 (c)
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$default reduce using rule 5 (b)]], [[
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$end reduce using rule 5 (b)
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'a' reduce using rule 5 (b)
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'b' reduce using rule 6 (c)]])[
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b go to state 5
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c go to state 6
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state 4
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0 $accept: start $end .
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$default accept
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state 5
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1 start: a b . [$end]
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2 | a b . 'a'
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'a' shift, and go to state 7
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]AT_COND_CASE([[all]], [[$default]], [[$end]])[ reduce using rule 1 (start)
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state 6
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3 start: a c . 'b'
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'b' shift, and go to state 8
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state 7
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2 start: a b 'a' .]AT_COND_CASE([[accepting]], [[ [$end]
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$end reduce using rule 2 (start)]], [[
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$default reduce using rule 2 (start)]])[
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state 8
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3 start: a c 'b' .]AT_COND_CASE([[accepting]], [[ [$end]
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$end reduce using rule 3 (start)]], [[
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$default reduce using rule 3 (start)]])[
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]])
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