#!perl
# Marpa::R3 is Copyright (C) 2016, Jeffrey Kegler.
#
# This module is free software; you can redistribute it and/or modify it
# under the same terms as Perl 5.10.1. For more details, see the full text
# of the licenses in the directory LICENSES.
#
# This program is distributed in the hope that it will be
# useful, but it is provided “as is” and without any express
# or implied warranties. For details, see the full text of
# of the licenses in the directory LICENSES.

use 5.010001;

# This test is new with Marpa::R3
# A test of the warning for "too many Earley items"
# Uses a grammar which creates the Catalan numbers

use strict;
use warnings;
use POSIX qw(setlocale LC_ALL);

POSIX::setlocale(LC_ALL, "C");

use Test::More tests => 2;
use lib 'inc';
use Marpa::R3::Test;
use Marpa::R3;

my $grammar = Marpa::R3::Scanless::G->new(
    {
        source => \<<'END_OF_DSL',
pair ::= a a
pair ::= pair a
pair ::= a pair
pair ::= pair pair
a ~ 'a'
END_OF_DSL
    }
);

sub do_pairings {
    my $n           = shift;
    my $parse_count = 0;

    my $recce = Marpa::R3::Scanless::R->new(
        { grammar => $grammar, too_many_earley_items => 10 } );

    # An arbitrary maximum is put on the number of parses -- this is for
    # debugging, and infinite loops happen.
    $recce->set( { max_parses => 999, } );

    my $trace_output;
    open my $trace_fh, q{>}, \$trace_output;
    $recce->set( { trace_file_handle => $trace_fh } );

    $recce->read( \( 'a' x $n ) );

    $recce->set( { trace_file_handle => \*STDOUT } );
    close $trace_fh;

    my $expected_trace_output = <<'END_OF_TRACE';
G1 exceeded earley item threshold at pos 2: 11 Earley items
END_OF_TRACE

    Marpa::R3::Test::is( $trace_output, $expected_trace_output,
        '"Too many Earley items" Trace Output' );

} ## end sub do_pairings

my @catalan_numbers = ( 0, 1, 1, 2, 5, 14, 42, 132, 429 );

for my $a ( 2 ) {

    my $actual_parse_count = do_pairings($a);
    Marpa::R3::Test::is( $actual_parse_count, $catalan_numbers[$a],
        "Catalan number $a matches parse count ($actual_parse_count)" );

} ## end for my $a ( ( 2 .. 8 ) )

1;    # In case used as "do" file

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