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\title{Interactive \TeX\ training and support}
\author{Jonathan Fine}
\address{J.Fine@pytex.org}
\TPJrevision{2007}{11}{21} % The editors ask you to update this for each revision submitted
\TPJcopyright{ } % May be used if you want a copyright notice at the bottom right of the first page
\website{http://jonathanfine.wordpress.com/} \abstract{ It is today practical
and helpful to provide \TeX\ as a web service.  This allows us a new approach
to learning \TeX. }

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The website \url{http://www.mathtran.org} (developed by the author,
with funding from the UK's JISC and Open University) runs \TeX\ as a
daemon and provides translation of \TeX-notation mathematical formulas
into bitmap graphics as a web service.  It takes less than 10
milliseconds per image to do this translation (not including time take
to serve the image), which is quicker than looking it up on an average
hard drive.  At present, this site is serving about 30,000 images a
day, out of a potential capacity of perhaps 2,000,000.

Troy Henderson's \LaTeX\ previewer
\url{http://www.tlhiv.org/LaTeXpreviewer/} and the SITMO equation
editor \url{http://www.sitmo.com/latex/} both offer \LaTeX\ as a web
service.  Here, they run \LaTeX\ once for each request.  Although not
quick enough to support a public service for web page graphic, they
are easily quick enough to process individual user generated
requests.

Recently, one of the \TeX\ users I support asked a question about
breaking an equation over two lines.  Previously it was set page
width, and she had to reformat it for double column.  The original
equation used \texttt{\string\left} and \texttt{\string\right} to give
variable size delimiters.  When she, in the usual way, used
\texttt{align} to break the equation, she found that
\texttt{\string\left} and \texttt{\string\right} no longer worked.

The solution is to use one of the \texttt{\string\big} family of
commands.  I looked for a web page that explained this.  To my
surprise, I did not find one.  Worse, there was no easy way I could
create one.  So instead of doing that, and sending my user a newly
created \TeX-support URL, I sent an email.

\samepage{The Django website \url{http://www.djangosnippets.org/} is a modern
example of how to store and serve user-contributed content.  The code for the
site (but not the design) is open-source, and so can be copied.  We can follow
this example.

It is now time to integrate \TeX\ as a web service into web pages that provide
\TeX\ support and training, and to allow users to edit these pages. }
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