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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/.
use 5.010001;
use strict;
use warnings;
use Test::More tests => 10;
use lib 'inc';
use Marpa::R2::Test;
use Marpa::R2;
# The inefficiency (at least some of it) is deliberate.
# Passing up a duples of [ string, value ] and then
# assembling a final string at the top would be better
# than assembling the string then taking it
# apart at each step. But I wanted to test having
# a start symbol that appears repeatedly on the RHS.
## no critic (Subroutines::RequireArgUnpacking)
sub subtraction {
shift;
my ( $right_string, $right_value ) = ( $_[2] =~ /^(.*)==(.*)$/xms );
my ( $left_string, $left_value ) = ( $_[0] =~ /^(.*)==(.*)$/xms );
my $value = $left_value - $right_value;
return '(' . $left_string . q{-} . $right_string . ')==' . $value;
} ## end sub subtraction
sub postfix_decr {
shift;
my ( $string, $value ) = ( $_[0] =~ /^(.*)==(.*)$/xms );
return '(' . $string . q{--} . ')==' . $value--;
}
sub prefix_decr {
shift;
my ( $string, $value ) = ( $_[1] =~ /^(.*)==(.*)$/xms );
return '(' . q{--} . $string . ')==' . --$value;
}
sub negation {
shift;
my ( $string, $value ) = ( $_[1] =~ /^(.*)==(.*)$/xms );
return '(' . q{-} . $string . ')==' . -$value;
}
sub number {
shift;
my $value = $_[0];
return "$value==$value";
}
sub default_action {
shift;
return q{} if scalar @_ <= 0;
return $_[0] if scalar @_ == 1;
return '(' . join( q{;}, @_ ) . ')';
} ## end sub default_action
## use critic
my $grammar = Marpa::R2::Grammar->new(
{ start => 'E',
actions => 'main',
rules => [
{ lhs => 'E',
rhs => [qw/E Minus E/],
action => 'subtraction',
},
{ lhs => 'E',
rhs => [qw/E MinusMinus/],
action => 'postfix_decr',
},
{ lhs => 'E',
rhs => [qw/MinusMinus E/],
action => 'prefix_decr',
},
{ lhs => 'E',
rhs => [qw/Minus E/],
action => 'negation'
},
{ lhs => 'E',
rhs => [qw/Number/],
action => 'number'
},
],
# Marpa::R2::Display
# name: Symbol descriptor example
symbols => {
MinusMinus => { terminal => 1 },
Minus => { terminal => 1 },
Number => { terminal => 1 },
},
# Marpa::R2::Display::End
default_action => 'default_action',
},
);
$grammar->precompute();
my $recce = Marpa::R2::Recognizer->new( { grammar => $grammar } );
Marpa::R2::Test::is( $grammar->show_rules,
<<'END_RULES', 'Minuses Equation Rules' );
0: E -> E Minus E
1: E -> E MinusMinus
2: E -> MinusMinus E
3: E -> Minus E
4: E -> Number
END_RULES
Marpa::R2::Test::is( $grammar->show_ahms,
<<'END_AHMS', 'Minuses Equation AHMs' );
AHM 0: postdot = "E"
E ::= . E Minus E
AHM 1: postdot = "Minus"
E ::= E . Minus E
AHM 2: postdot = "E"
E ::= E Minus . E
AHM 3: completion
E ::= E Minus E .
AHM 4: postdot = "E"
E ::= . E MinusMinus
AHM 5: postdot = "MinusMinus"
E ::= E . MinusMinus
AHM 6: completion
E ::= E MinusMinus .
AHM 7: postdot = "MinusMinus"
E ::= . MinusMinus E
AHM 8: postdot = "E"
E ::= MinusMinus . E
AHM 9: completion
E ::= MinusMinus E .
AHM 10: postdot = "Minus"
E ::= . Minus E
AHM 11: postdot = "E"
E ::= Minus . E
AHM 12: completion
E ::= Minus E .
AHM 13: postdot = "Number"
E ::= . Number
AHM 14: completion
E ::= Number .
AHM 15: postdot = "E"
E['] ::= . E
AHM 16: completion
E['] ::= E .
END_AHMS
my %expected = map { ( $_ => 1 ) } (
#<<< no perltidy
'(((6--)--)-1)==5',
'((6--)-(--1))==6',
'((6--)-(-(-1)))==5',
'(6-(--(--1)))==7',
'(6-(--(-(-1))))==6',
'(6-(-(--(-1))))==4',
'(6-(-(-(--1))))==6',
'(6-(-(-(-(-1)))))==5',
#>>>
);
$recce->read( 'Number', '6' );
for ( 1 .. 4 ) {
$recce->alternative( 'MinusMinus', \q{--}, 2 );
$recce->alternative( 'Minus', \q{-} );
$recce->earleme_complete();
}
$recce->read( 'Minus', q{-}, );
$recce->read( 'Number', '1' );
# Set max_parses to 20 in case there's an infinite loop.
# This is for debugging, after all
$recce->set( { max_parses => 20 } );
while ( my $value_ref = $recce->value() ) {
my $value = $value_ref ? ${$value_ref} : 'No parse';
if ( defined $expected{$value} ) {
delete $expected{$value};
Test::More::pass("Expected Value $value");
}
else {
Test::More::fail("Unexpected Value $value");
}
} ## end while ( my $value_ref = $recce->value() )
1; # In case used as "do" file
# Local Variables:
# mode: cperl
# cperl-indent-level: 4
# fill-column: 100
# End:
# vim: expandtab shiftwidth=4:
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