#!perl
# Copyright 2014 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/.
# The example from p. 166 of Leo's paper.
use 5.010;
use strict;
use warnings;
use Test::More tests => 9;
use lib 'inc';
use Marpa::R2::Test;
use Marpa::R2;
## no critic (Subroutines::RequireArgUnpacking)
sub main::default_action {
shift;
return ( join q{}, grep {defined} @_ );
}
## use critic
my $grammar = Marpa::R2::Grammar->new(
{ start => 'S',
rules => [ [ 'S', [qw/a S/] ], [ 'S', [], ], ],
terminals => [qw(a)],
default_action => 'main::default_action',
}
);
$grammar->precompute();
Marpa::R2::Test::is( $grammar->show_symbols(),
<<'END_OF_STRING', 'Leo166 Symbols' );
0: a, terminal
1: S
END_OF_STRING
Marpa::R2::Test::is( $grammar->show_rules,
<<'END_OF_STRING', 'Leo166 Rules' );
0: S -> a S
1: S -> /* empty !used */
END_OF_STRING
Marpa::R2::Test::is( $grammar->show_ahms, <<'END_OF_STRING', 'Leo166 AHMs' );
AHM 0: postdot = "a"
S ::= . a S
AHM 1: postdot = "S"
S ::= a . S
AHM 2: completion
S ::= a S .
AHM 3: postdot = "a"
S ::= . a S[]
AHM 4: completion
S ::= a S[] .
AHM 5: postdot = "S"
S['] ::= . S
AHM 6: completion
S['] ::= S .
END_OF_STRING
my $length = 50;
LEO_FLAG: for my $leo_flag ( 0, 1 ) {
my $recce = Marpa::R2::Recognizer->new(
{ grammar => $grammar, leo => $leo_flag } );
my $i = 0;
# Marpa::R2::Display
# name: latest_earley_set() Synopsis
my $latest_earley_set = $recce->latest_earley_set();
# Marpa::R2::Display::End
my $max_size = $recce->earley_set_size($latest_earley_set);
TOKEN: while ( $i++ < $length ) {
$recce->read( 'a', 'a' );
$latest_earley_set = $recce->latest_earley_set();
my $size = $recce->earley_set_size($latest_earley_set);
$max_size = $size > $max_size ? $size : $max_size;
} ## end while ( $i++ < $length )
my $expected_size = $leo_flag ? 6 : $length + 4;
Marpa::R2::Test::is( $max_size, $expected_size,
"Leo flag $leo_flag, size" );
my $value_ref = $recce->value();
my $value = $value_ref ? ${$value_ref} : 'No parse';
Marpa::R2::Test::is( $value, 'a' x $length, 'Leo p166 parse' );
} ## end for my $leo_flag ( 0, 1 )
{
open my $trace_fh, q{>}, \( my $trace_output = q{} );
my $recce = Marpa::R2::Recognizer->new(
{ grammar => $grammar,
leo => 0,
too_many_earley_items => $length,
trace_fh => $trace_fh
}
);
for ( 1 .. $length ) { $recce->read( 'a', 'a' ); }
my $value_ref = $recce->value();
close $trace_fh;
my $warning_found =
( $trace_output
=~ m/Earley[ ]item[ ]count[ ()\d]*exceeds[ ]warning[ ]threshold/xms
);
if ($warning_found) {
Test::More::pass('Warns at earley item threshold');
}
else {
Marpa::R2::Test::is( $trace_output, q{}, 'Leo p166 parse' );
}
my $value = $value_ref ? ${$value_ref} : 'No parse';
Marpa::R2::Test::is( $value, 'a' x $length, 'Leo p166 parse' );
}
1; # In case used as "do" file
# Local Variables:
# mode: cperl
# cperl-indent-level: 4
# fill-column: 100
# End:
# vim: expandtab shiftwidth=4: