If I'm asking in the wrong place, please tell me where to go.
What I would like to do is
<HTML>
<form action="html://nowhere.nul/cgi-bin/further_processing.php"> method="post">
...
<input type="hidden" name="from" value = "@USER@ <@MAIL@>" >
...
<submit>
...
</form>
</HTML>
But the @VAR@ variables do not work inside <input> and probably not anywhere inside HTML. I've tried all variations I can think of for
value ="</HTML> @USER@ <@MAIL@> <HTML>" >
without success. I had hoped that Bureaucracy would enable this kind of thing, still without success. I have attempted to inject the user and mail info into the POST string with Javascript and with PHP, but my skills with either one are not up to the task. Also I think that would be stepping away from the simple usage I want to leave to whoever has to follow me to fancy-dancing in a custom plugin.
Further info: The form would reside in a namespace that only logged in members could access. The idea is to assure that the "From: " field of the email is always a registered user's name and address. The further_processing.php would actually send the mail, but might also feed data to some statistics package that tracks user feedback, or possibly some regex php routine to analyze the content of the message field.
So please tell me I'm overlooking something very simple, or that someone has already built a plugin that will do what I want. Three days of googling for an answer has found nothing relevant. Which makes me think that I'm looking at the problem all wrong.