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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/.
# An ambiguous equation
use 5.010001;
use strict;
use warnings;
use Test::More tests => 1;
use lib 'inc';
use Marpa::R2::Test;
use English qw( -no_match_vars );
use Fatal qw(open close);
use Marpa::R2;
## no critic (InputOutput::RequireBriefOpen)
open my $original_stdout, q{>&STDOUT};
## use critic
sub save_stdout {
my $save;
my $save_ref = \$save;
close STDOUT;
open STDOUT, q{>}, $save_ref;
return $save_ref;
} ## end sub save_stdout
sub restore_stdout {
close STDOUT;
open STDOUT, q{>&}, $original_stdout;
return 1;
}
# Marpa::R2::Display
# name: Null Value Example
sub do_L {
shift;
return 'L(' . ( join q{;}, map { $_ // '[ERROR!]' } @_ ) . ')';
}
sub do_R {
return 'R(): I will never be called';
}
sub do_S {
shift;
return 'S(' . ( join q{;}, map { $_ // '[ERROR!]' } @_ ) . ')';
}
sub do_X { return 'X(' . $_[1] . ')'; }
sub do_Y { return 'Y(' . $_[1] . ')'; }
## no critic (Variables::ProhibitPackageVars)
our $null_A = 'null A';
our $null_B = 'null B';
our $null_L = 'null L';
our $null_R = 'null R';
our $null_X = 'null X';
our $null_Y = 'null Y';
## use critic
my $grammar = Marpa::R2::Grammar->new(
{ start => 'S',
actions => 'main',
rules => [
[ 'S', [qw/L R/], 'do_S' ],
[ 'L', [qw/A B X/], 'do_L' ],
[ 'L', [], 'null_L' ],
[ 'R', [qw/A B Y/], 'do_R' ],
[ 'R', [], 'null_R' ],
[ 'A', [], 'null_A' ],
[ 'B', [], 'null_B' ],
[ 'X', [], 'null_X' ],
[ 'X', [qw/x/], 'do_X' ],
[ 'Y', [], 'null_Y' ],
[ 'Y', [qw/y/], 'do_Y' ],
],
}
);
$grammar->precompute();
my $recce = Marpa::R2::Recognizer->new( { grammar => $grammar } );
$recce->read( 'x', 'x' );
# Marpa::R2::Display::End
## use critic
# Marpa::R2::Display
# name: Null Value Example Output
# start-after-line: END_OF_OUTPUT
# end-before-line: '^END_OF_OUTPUT$'
chomp( my $expected = <<'END_OF_OUTPUT');
S(L(null A;null B;X(x));null R)
END_OF_OUTPUT
# Marpa::R2::Display::End
my $value = $recce->value();
Marpa::R2::Test::is( ${$value}, $expected, 'Null example' );
1; # In case used as "do" file
# Local Variables:
# mode: cperl
# cperl-indent-level: 4
# fill-column: 100
# End:
# vim: expandtab shiftwidth=4:
|
