Re: Agenda for teleconference Wednesday October 24, 2007

On Mittwoch, 24. Oktober 2007, Peter F. Patel-Schneider wrote:
<snip>
> >
> > I think there is a whitelist of commands that are allowed in the wiki.
> > This is, I think, a security issue (since TeX is a complex programming
> > language that may have undesired side-effects when running user-built
> > programs on the server).
>
> Sure, there may have to be some limitations.  What are they?

Sorry, no idea (but see my notes below).

<snip>

> >
> > AFAIK the wiki builds its search index on the input text, not on the
> > output HTML. Moreover, all the PNGs will have the (La)TeX code as an
> > alternative text label (so that text-browsers can read stuff as well, and
> > smart web searches may index it).
>
> Well, I don't see how to get firefox to look for all uses of "a" in a
> document that includes texvc.  In fact, the situation is precisely the
> worst of all worlds: *some* uses of "a" in the texvc output are
> included, which can give rise to the the expectation that *all* uses of
> "a" in the document are included.  For an example of how the search
> fails try searching for a in
> http://meta.wikimedia.org/wiki/Help:Displaying_a_formula, and then
> highlight all matches.

My comment applied to searching via search engines or the wiki's (weak) 
internal text search. But finding text-matches with a browser is of course 
difficult if you want to use inline formulae that cannot be displayed as text 
by modern browsers. Note, however, that you can instruct MediaWiki how to 
treat <math>-parts in your user preferences. You can make it use HTML very 
aggressively (more complete text search, inferior display), or even to show 
only LaTeX instead of the rendered result (complete text search, no proper 
display). I know it's not perfect, but probably not worse than the math 
support of other CMS.

>
> > > I don't see anything about user-defined commands on the page, from
> > > which I take it that they are not allowed.  This is a very serious
> > > lack!  Of course, HTML also has a problem here.
> >
> > This might be easy to fix, if we have a *fixed* set of common
> > user-defined add-ons/packages to use in the wiki tex. We basically can
> > change the preamble of the TeX that is used to make the formulae as we
> > like. I do not know whether and how this could be done through the wiki,
> > though.
>
> I wonder whether \newcommand is on the whitelist.

Probably not. I guess the command list at the end of [1] is complete (but then 
again I don't speak OCAML). By the way: this file is also the one where one 
can directly influence the LaTeX settings used for creating the PNGs (e.g. by 
extending the \usepackage seetings), where "make" must be run after any 
change. Someone with moderate ML skills might be able to remove the LaTeX 
restrictions.

Markus

[1] http://svn.wikimedia.org/svnroot/mediawiki/trunk/phase3/math/texutil.ml

-- 
Markus Krötzsch
Institut AIFB, Universät Karlsruhe (TH), 76128 Karlsruhe
phone +49 (0)721 608 7362        fax +49 (0)721 608 5998
mak@aifb.uni-karlsruhe.de        www  http://korrekt.org