I usually have success in this argument by "ignoring the question they asked and answering the question I wish they had asked me."
That is, I don't talk about tcl vs php/java/perl etc, but redirect the discussion to focus architectural choices. Then I extoll the virtues of AOLserver.
It is much easier to position the OpenACS as a toolkit built around a wonderful piece of software that runs AOL.com, Mapquest.com, Netscape.com, Moviefone.com, etc than it is to fight Tcl's relative obscurity.
Once I position it in terms of its success in the real world, I open up the technical reasons for a preference of AOLserver, which are:
* Multi-threaded server (like apache 2, but done many years beforehand and is much more reliable)
* Pooled DB connections (like JDBC, but done many years beforehand.)
* Native DB APIs (also like JDBC, but built for particular DBs so more efficient)
* Embedded Tcl interpreter (lightweight, simple, extremely fast scipting that, in concert with the previous three characteristics, makes AOLserver an amazing web application framework.)
The collection of these characteristics make up what is Apache + mod_dbi + mod_favorite-language on steroids. Add in the AOLserver Dynamic Pages (and the OpenACS templating system) and there is a solution far more elegant than anything that PHP or Java offer.
If the fight continues after this, there's not much that can be done probably because the person is particularly set on PHP and Apache or is very against tcl and AOLserver.
If the person is really language agnostic, though, then this is usually a very compelling argument.
talli
