interfacing mathematics

[Chad Cunningham]

Hi everyone, I'm working on ways to put math on the web. I do a lot of
web based programming in PHP, which of course doesn't handle any
advanced mathematics. What I'm considering doing is trying to somehow
add a native inteface to a mathematics package to php so as to avoid the
overhead of running an external program or CGI. It would probably be
good to do this with Mathematica using the MathLink libraries, but I
have a feeling the licensing would be prohibitive. Several people have
pointed me at octave. Is there a C API Library available for octave? All
I would really need to do is write wrapper functions in the PHP API. Has
anyone done anything like this before?