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#!perl
# Copyright 2022 Jeffrey Kegler
# This file is part of Marpa::R2. Marpa::R2 is free software: you can
# redistribute it and/or modify it under the terms of the GNU Lesser
# General Public License as published by the Free Software Foundation,
# either version 3 of the License, or (at your option) any later version.
#
# Marpa::R2 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser
# General Public License along with Marpa::R2. If not, see
# http://www.gnu.org/licenses/.
# Tests of ambiguity detection in the target grammar
# (as opposed to the SLIF DSL itself).
use 5.010001;
use strict;
use warnings;
use Test::More tests => 11;
use English qw( -no_match_vars );
use lib 'inc';
use Marpa::R2::Test;
use Marpa::R2;
use Data::Dumper;
our $DEBUG = 0;
my $source = \(<<'END_OF_SOURCE');
:default ::= action => ::array
pair ::= duple | item item
duple ::= item item
item ::= Hesperus | Phosphorus
Hesperus ::= 'a'
Phosphorus ::= 'a'
END_OF_SOURCE
my $input = 'aa';
my $expected_value = 'Application grammar is ambiguous';
my $expected_result = <<'END_OF_MESSAGE';
Ambiguous symch at Glade=2, Symbol=<pair>:
The ambiguity is from line 1, column 1 to line 1, column 2
Text is: aa
There are 2 symches
Symch 0 is a rule: pair ::= duple
Symch 1 is a rule: pair ::= item item
END_OF_MESSAGE
my $test_name = 'Symch ambiguity';
my $grammar = Marpa::R2::Scanless::G->new( { source => $source } );
my $recce = Marpa::R2::Scanless::R->new( { grammar => $grammar } );
my $is_ambiguous_parse = 1;
my ( $actual_value, $actual_result );
PROCESSING: {
if ( not defined eval { $recce->read( \$input ); 1 } ) {
say $EVAL_ERROR if $DEBUG;
my $abbreviated_error = $EVAL_ERROR;
chomp $abbreviated_error;
$abbreviated_error =~ s/\n.*//xms;
$actual_value = 'No parse';
$actual_result = $abbreviated_error;
$is_ambiguous_parse = 0;
last PROCESSING;
} ## end if ( not defined eval { $recce->read( \$input ); 1 })
# Marpa::R2::Display
# name: ASF ambiguity reporting
if ( $recce->ambiguity_metric() > 1 ) {
my $asf = Marpa::R2::ASF->new( { slr => $recce } );
die 'No ASF' if not defined $asf;
my $ambiguities = Marpa::R2::Internal::ASF::ambiguities($asf);
# Only report the first two
my @ambiguities = grep {defined} @{$ambiguities}[ 0 .. 1 ];
$actual_value = 'Application grammar is ambiguous';
$actual_result =
Marpa::R2::Internal::ASF::ambiguities_show( $asf, \@ambiguities );
last PROCESSING;
} ## end if ( $recce->ambiguity_metric() > 1 )
# Marpa::R2::Display::End
$is_ambiguous_parse = 0;
my $value_ref = $recce->value();
if ( not defined $value_ref ) {
$actual_value = 'No parse';
$actual_result = 'Input read to end but no parse';
last PROCESSING;
}
$actual_value = ${$value_ref};
$actual_result = 'Parse OK';
last PROCESSING;
} ## end PROCESSING:
Test::More::is(
Data::Dumper::Dumper( \$actual_value ),
Data::Dumper::Dumper( \$expected_value ),
qq{Value of $test_name}
);
Test::More::is( $actual_result, $expected_result, qq{Result of $test_name} );
if ( !$is_ambiguous_parse ) {
Test::More::fail(qq{glade_span() start});
Test::More::fail(qq{glade_span() length});
}
else {
$recce->series_restart();
my $asf = Marpa::R2::ASF->new( { slr => $recce } );
my $glade_id = $asf->peak;
# Marpa::R2::Display
# name: glade_span() example
my ( $glade_start, $glade_length ) = $asf->glade_span($glade_id);
# Marpa::R2::Display::End
Test::More::is( $glade_start, 0, qq{glade_span() start} );
Test::More::is( $glade_length, 2, qq{glade_span() length} );
} ## end else [ if ( !$is_ambiguous_parse ) ]
# Tests of ambiguity_metric() anb ambiguous() across all ranking methods
$source = \(<<'END_OF_SOURCE');
lexeme default = latm => 1
top ::= unchoice rank => 1
top ::= choice
unchoice ::= choice1
choice ::= choice1 | choice2
choice1 ::= A1 B1
choice2 ::= A2 B2
A1 ~ 'a'
A2 ~ 'a'
B1 ~ 'b'
B2 ~ 'b'
:discard ~ ws
ws ~ [\s]+
END_OF_SOURCE
$grammar = Marpa::R2::Scanless::G->new({ source => $source });
$input = q{a b};
for my $ranking_method ('none', 'rule', 'high_rule_only'){
$recce = Marpa::R2::Scanless::R->new({
grammar => $grammar,
ranking_method => $ranking_method,
} );
$recce->read(\$input);
if ($ranking_method eq 'high_rule_only'){
# count parses and test that there is only one
my $parse_count = 0;
while (defined $recce->value()) { ++$parse_count }
Test::More::is( $parse_count, 1, "$ranking_method ranking, single parse" );
# reset recognizer and test ambiguity methods
$recce->series_restart();
Test::More::is( $recce->ambiguous(), '', "$ranking_method ranking, single parse, ambiguous status is empty" );
Test::More::is( $recce->ambiguity_metric(), 1, "$ranking_method ranking, single parse, ambiguity metric is 1" );
}
else{
Test::More::isnt( $recce->ambiguous(), '', "$ranking_method ranking, many parses, ambiguous status isn't empty" );
Test::More::ok( $recce->ambiguity_metric() > 1, "$ranking_method ranking, many parses, ambiguity metric > 1" );
}
} ## end for my $ranking_method ...
# vim: expandtab shiftwidth=4:
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