while (my $line_in = <DATA>) {
  chomp($line_in);
  next if $line_in =~ /^#/; # skip comments
  
  my ( $style, $content ) = $line_in =~ /^(\w)\s+(.*)$/;
  my $block = $tag->{ $style }->{ block };
  
  $line_out = join( '',
                    $tag->{ $style }->{ open },
                    $content,
                    $tag->{ $style }->{ close } );

  if ( $block and ! $block_flag ){
    $output = join( '',
                    $output,
                    $tag->{ $style }->{ block_open },
                    $line_out,
                    ',' );
    $block_flag = $style;
  }
  elsif ( ! $block and $block_flag ){
    chop $output; # remove final comma
    $output = join( '',
                    $output,
                    $tag->{ $block_flag }->{ block_close },
                    "\n",
                    $line_out,
                    "\n" );
    $block_flag = '';
  }
  elsif ( $block ){
    $output = join( '',
                    $output,
                    $line_out,
                    ',' );

  }
  else{
    $output = join( '',
                    $output,
                    $line_out,
                    "\n" );
  }
  $line_out = '';
}

# data with comments

__DATA__
R Whatever
# First comment
R Another whatever
K Perl
K Monks
# Second comment
K Is
K Cool
T Another style
R Whatever