lib/Language/Befunge/lib/REFC.pm

   1 #
   2 # This file is part of Language::Befunge.
   3 # Copyright (c) 2001-2009 Jerome Quelin, all rights reserved.
   4 #
   5 # This program is free software; you can redistribute it and/or modify
   6 # it under the same terms as Perl itself.
   7 #
   8 #
   9
  10 package Language::Befunge::lib::REFC;
  11
  12 use strict;
  13 use warnings;
  14
  15 use Language::Befunge::Vector;
  16
  17 sub new { return bless {}, shift; }
  18
  19 my @vectors;
  20
  21
  22 #
  23 # $id = R( $x, $y )
  24 #
  25 # 'Reference' pops a vector off the stack, and pushes a scalar value back onto
  26 # the stack, unique within an internal list of references, which refers to that
  27 # vector.
  28 #
  29 sub R {
  30         my ($self, $lbi) = @_;
  31         my $ip = $lbi->get_curip;
  32         my $v  = $ip->spop_vec;
  33         push @vectors, $v;
  34         $ip->spush( $#vectors );
  35 }
  36
  37
  38 #
  39 # ($x, $y) = D( $id )
  40 #
  41 # 'Dereference' pops a scalar value off the stack, and pushes the vector back
  42 # onto the stack which corresponds to that unique reference value.
  43 #
  44 sub D {
  45         my ($self, $lbi) = @_;
  46         my $ip = $lbi->get_curip;
  47         my $id = $ip->spop;
  48         my $v = $vectors[$id];
  49         $ip->spush( $v->get_component(0), $v->get_component(1) );
  50 }
  51
  52
  53 1;
  54
  55 __END__
  56
  57
  58 =head1 NAME
  59
  60 Language::Befunge::IP::lib::REFC - Referenced cells extension
  61
  62
  63
  64 =head1 DESCRIPTION
  65
  66
  67 The REFC fingerprint (0x52454643) allows vectors to be encoded into and
  68 decoded from single scalar cell values.
  69
  70 Note that the internal list of references is considered shared among all
  71 IP's.
  72
  73
  74
  75 =head1 FUNCTIONS
  76
  77 =head2 new
  78
  79 Create a new REFC instance.
  80
  81
  82 =head2 De/Referencing
  83
  84 =over 4
  85
  86 =item $id = R( $x, $y )
  87
  88 C<Reference> pops a vector off the stack, and pushes a scalar value back onto
  89 the stack, unique within an internal list of references, which refers to that
  90 vector.
  91
  92
  93 =item ($x, $y) = D( $id )
  94
  95 C<Dereference> pops a scalar value off the stack, and pushes the vector back
  96 onto the stack which corresponds to that unique reference value.
  97
  98
  99 =back
 100
 101
 102
 103 =head1 SEE ALSO
 104
 105 L<Language::Befunge>, L<http://catseye.tc/projects/funge98/library/REFC.html>.
 106
 107
 108
 109 =head1 AUTHOR
 110
 111 Jerome Quelin, C<< <jquelin@cpan.org> >>
 112
 113
 114 =head1 COPYRIGHT & LICENSE
 115
 116 Copyright (c) 2001-2009 Jerome Quelin, all rights reserved.
 117
 118 This program is free software; you can redistribute it and/or modify
 119 it under the same terms as Perl itself.
 120
 121
 122 =cut