Defining a procedure with "ad_proc" instead of the usual "proc"
command offers many advantages such as defining switches, etc.
However, there is a catch. Let's say you call a function to
convert a variable from text to HTML:
ad_text_to_html $message
If the $message variable contains a "-" as the first character,
then that will get interpreted as a switch to the "ad_text_to_html"
procedure, and an error will result.
The solution is to utilize "--" to denote that there are no more
switches following and that $message is the first argument:
ad_text_to_html -- $message
Sorry if you already knew this, but I'm posting this in the hopes
that it might help somebody some day... =)