Trivial, but posted here in case it is useful for someone:
facebook instproc render {} {
my get_parameters
my instvar __including_page
set url "[ad_conn location][$__including_page pretty_link]"
set facebook_link [export_vars -base "http://www.facebook.com/plugins/like.php" {
{url $url}
}]
regsub -all & $facebook_link "&" facebook_link
return "<iframe src='$facebook_link' scrolling='no' frameborder='0' style='border:none; width:450px; height:80px;'></iframe>"
}
::xowiki::IncludeletClass create delicious \
-superclass ::xowiki::Includelet \
-parameter {
{__decoration none}
{parameter_declaration {
{-url}
}}
}