Introduce LaTeX::TikZ::Functor

[perl/modules/LaTeX-TikZ.git] / lib / LaTeX / TikZ / Functor.pm

diff --git a/lib/LaTeX/TikZ/Functor.pm b/lib/LaTeX/TikZ/Functor.pm
new file mode 100644 (file)
index 0000000..e302d3f
--- /dev/null
+++ b/lib/LaTeX/TikZ/Functor.pm
@@ -0,0 +1,168 @@
+package LaTeX::TikZ::Functor;
+
+use strict;
+use warnings;
+
+=head1 NAME
+
+LaTeX::TikZ::Functor - Build functor methods that recursively visit nodes of a LaTeX::TikZ::Set tree.
+
+=head1 VERSION
+
+Version 0.01
+
+=cut
+
+our $VERSION = '0.01';
+
+use Carp ();
+
+use Sub::Name ();
+
+use LaTeX::TikZ::Tools;
+
+use Any::Moose 'Util' => [ 'does_role' ];
+
+my $lts_tc = LaTeX::TikZ::Tools::type_constraint('LaTeX::TikZ::Set');
+
+my @default_set_rules;
+my @default_mod_rules;
+
+my ($validate_rule, $insert_rule);
+BEGIN {
+ $validate_rule = Sub::Name::subname('validate_rule' => sub {
+  my ($target, $handler) = @_;
+
+  unless (defined $target and ref $target eq ''
+          and $target =~ /[A-Za-z][A-Za-z0-9_]*(?:::[A-Za-z][A-Za-z0-9_]*)*/) {
+   Carp::confess("Invalid target $target");
+  }
+
+  (my $pm = $target) =~ s{::}{/}g;
+  $pm .= '.pm';
+  require $pm;
+
+  my $is_set;
+  if (does_role($target, 'LaTeX::TikZ::Set')) {
+   $is_set = 1;
+  } elsif (does_role($target, 'LaTeX::TikZ::Mod')) {
+   $is_set = 0;
+  } else {
+   Carp::confess("Target $target is neither a set nor a mod");
+  }
+
+  Carp::confess("Invalid handler for target $target")
+                                                  unless ref $handler eq 'CODE';
+
+  return [ $target, $handler, $is_set ];
+ });
+
+ $insert_rule = Sub::Name::subname('insert_rule' => sub {
+  my ($rule, $list) = @_;
+
+  my $spec = $rule->[0];
+  for my $i (0 .. $#$list) {
+   my $old_spec = $list->[$i]->[0];
+   if ($old_spec->isa($spec) or does_role($old_spec, $spec)) {
+    splice @$list, $i, 1, $rule;
+    return 1;
+   }
+  }
+
+  push @$list, $rule;
+  return $#$list;
+ });
+}
+
+sub default_rule {
+ shift;
+
+ my $rule = $validate_rule->(@_);
+
+ $insert_rule->($rule, $rule->[2] ? \@default_set_rules : \@default_mod_rules);
+}
+
+sub new {
+ my ($class, %args) = @_;
+
+ my @set_rules = @default_set_rules;
+ my @mod_rules = @default_mod_rules;
+
+ my @user_rules = @{$args{rules} || []};
+ while (@user_rules) {
+  my ($target, $handler) = splice @user_rules, 0, 2;
+
+  my $rule = $validate_rule->($target, $handler);
+
+  $insert_rule->($rule, $rule->[2] ? \@set_rules : \@mod_rules);
+ }
+
+ my %dispatch  = map { $_->[0] => $_ } @set_rules, @mod_rules;
+
+ my $self;
+
+ $self = bless sub {
+  my $set = shift;
+
+  $lts_tc->assert_valid($set);
+
+  my $rule = $dispatch{ref($set)};
+  unless ($rule) {
+   ($set->isa($_->[0]) or $set->does($_->[0])) and $rule = $_ for @set_rules;
+   $rule = [ undef, sub { $_[1] } ] unless $rule;
+  }
+  my $new_set = $rule->[1]->($self, $set, @_);
+  my $is_new  = $new_set ne $set;
+
+  my @new_mods;
+MOD:
+  for my $mod ($set->mods) {
+   my $rule = $dispatch{ref($mod)};
+   unless ($rule) {
+    ($mod->isa($_->[0]) or $mod->does($_->[0])) and $rule = $_ for @mod_rules;
+    unless ($rule) {
+     push @new_mods, $mod;
+     next MOD;
+    }
+   }
+   push @new_mods, $rule->[1]->($self, $mod, @_);
+  }
+
+  $new_set->mod(@new_mods) if $is_new;
+
+  return $new_set;
+ }, $class;
+}
+
+use LaTeX::TikZ::Interface functor => sub {
+ shift;
+
+ __PACKAGE__->new(rules => \@_);
+};
+
+=head1 AUTHOR
+
+Vincent Pit, C<< <perl at profvince.com> >>, L<http://www.profvince.com>.
+
+You can contact me by mail or on C<irc.perl.org> (vincent).
+
+=head1 BUGS
+
+Please report any bugs or feature requests to C<bug-latex-tikz at rt.cpan.org>, or through the web interface at L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=LaTeX-TikZ>.
+I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.
+
+=head1 SUPPORT
+
+You can find documentation for this module with the perldoc command.
+
+    perldoc LaTeX::TikZ
+
+=head1 COPYRIGHT & LICENSE
+
+Copyright 2010 Vincent Pit, all rights reserved.
+
+This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
+
+=cut
+
+1; # End of LaTeX::TikZ::Functor