# Copyright 2012 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
=head1 Name
Marpa::R2::Scanless::R - Scanless interface recognizers
=head1 This document is UNDER CONSTRUCTION
=head1 Synopsis
=for Marpa::R2::Display
name: Scanless recognizer synopsis
partial: 1
normalize-whitespace: 1
my $recce = Marpa::R2::Scanless::R->new( { grammar => $grammar } );
my $self = bless { grammar => $grammar }, 'My_Actions';
$self->{recce} = $recce;
local $My_Actions::SELF = $self;
my $event_count;
if ( not defined eval { $event_count = $recce->read($p_input_string); 1 }
)
{
## Add last expression found, and rethrow
my $eval_error = $EVAL_ERROR;
chomp $eval_error;
die $self->show_last_expression(), "\n", $eval_error, "\n";
} ## end if ( not defined eval { $event_count = $recce->read...})
if ( not defined $event_count ) {
die $self->show_last_expression(), "\n", $recce->error();
}
my $value_ref = $recce->value();
if ( not defined $value_ref ) {
die $self->show_last_expression(), "\n",
"No parse was found, after reading the entire input\n";
}
=for Marpa::R2::Display::End
=for Marpa::R2::Display
name: Scanless recognizer semantics
partial: 1
normalize-whitespace: 1
package My_Actions;
our $SELF;
sub new { return $SELF }
sub do_parens { shift; return $_[1] }
sub do_add { shift; return $_[0] + $_[2] }
sub do_subtract { shift; return $_[0] - $_[2] }
sub do_multiply { shift; return $_[0] * $_[2] }
sub do_divide { shift; return $_[0] / $_[2] }
sub do_pow { shift; return $_[0]**$_[2] }
sub do_first_arg { shift; return shift; }
sub do_script { shift; return join q{ }, @_ }
=for Marpa::R2::Display::End
=for Marpa::R2::Display
name: Scanless recognizer diagnostics
partial: 1
normalize-whitespace: 1
sub show_last_expression {
my ($self) = @_;
my $recce = $self->{recce};
my ( $start, $end ) = $recce->last_completed_range('Expression');
return 'No expression was successfully parsed' if not defined $start;
my $last_expression = $recce->range_to_string( $start, $end );
return "Last expression successfully parsed was: $last_expression";
} ## end sub show_last_expression
=for Marpa::R2::Display::End
=head1 About this document
This page is the reference document for the recognizer objects
of Marpa's Scanless interface.
=head1 Methods
=head2 error()
=head2 last_completed_range()
=head2 new()
=head2 range_to_string()
=head2 read()
=head2 show_progress()
=head2 trace()
=head2 value()
=head1 Copyright and License
=for Marpa::R2::Display
ignore: 1
Copyright 2012 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
=for Marpa::R2::Display::End
=cut
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