#! perl

#:META:RESOURCE:%.:string:autotransform expression

=head1 NAME

selection-autotransform - automatically transform select text

=head1 DESCRIPTION

This selection allows you to do automatic transforms on a selection
whenever a selection is made.

It works by specifying perl snippets (most useful is a single C<s///>
operator) that modify C<$_> as resources:

   URxvt.selection-autotransform.0: transform
   URxvt.selection-autotransform.1: transform
   ...

For example, the following will transform selections of the form
C<filename:number>, often seen in compiler messages, into C<vi +$filename
$word>:

   URxvt.selection-autotransform.0: s/^([^:[:space:]]+):(\\d+):?$/vi +$2 \\Q$1\\E\\x0d/

And this example matches the same,but replaces it with vi-commands you can
paste directly into your (vi :) editor:

   URxvt.selection-autotransform.0: s/^([^:[:space:]]+(\\d+):?$/:e \\Q$1\\E\\x0d:$2\\x0d/

Of course, this can be modified to suit your needs and your editor :)

To expand the example above to typical perl error messages ("XXX at
FILENAME line YYY."), you need a slightly more elaborate solution:

   URxvt.selection.pattern-0: ( at .*? line \\d+[,.])
   URxvt.selection-autotransform.0: s/^ at (.*?) line (\\d+)[,.]$/:e \\Q$1\E\\x0d:$2\\x0d/

The first line tells the selection code to treat the unchanging part of
every error message as a selection pattern, and the second line transforms
the message into vi commands to load the file.

=cut

sub msg {
   my ($self, $msg) = @_;

   my $overlay = $self->overlay (0, 0, $self->strwidth ($msg), 1);
   $overlay->set (0, 0, $msg);
   $self->{timer} = urxvt::timer->new->after (2)->cb (sub {
      delete $self->{timer};
      undef $overlay;
   });
}

sub on_init {
   my ($self) = @_;

   for (my $idx = 0; defined (my $res = $self->x_resource ("%.$idx")); $idx++) {
      $res = $self->locale_decode ($res);
      my $transform = eval "sub { $res }";

      if ($transform) {
         push @{ $self->{transforms} }, $transform;
      } else {
         warn "$res: $@";
      }
   }

   $self->{enabled} = 1;

   push @{ $self->{term}{option_popup_hook} }, sub {
      ("autotransform" => $self->{enabled}, sub { $self->{enabled} = shift })
   };

   ()
}

sub on_sel_grab {
   my ($self) = @_;

   $self->{enabled}
      or return;

   my $text = $self->selection;
   local $_ = $text;

   for my $transform (@{ $self->{transforms} }) {
      $transform->();
      if ($text ne $_) {
         $self->selection ($_);
         s/[\x00-\x1f\x80-\x9f]/·/g;
         $self->msg ($self->special_encode ("auto-transformed to $_"));
         last;
      }
   }

   ()
}