[racket] Network ports, sandboxes?

[I am changing the subject line so that it may be easier to track the
conversation.]


You can see examples of port usage (including an example of tcp) here
on this page:

    http://docs.racket-lang.org/guide/ports.html


You'll want to look into getting familiar with the general input and
output functions in Racket before handling network input and output.
See:

    http://docs.racket-lang.org/guide/i_o.html

which talks about input and output ports, and the functions that work
on them.  To the best of my knowledge, there is no special syntax
involved with ports alone: just learn a few of the common functions
such as read-line, write, and other functions described in the Guide.



About sandboxes: they're a tool to do dynamic evaluation in a context
that limits their resource usage.  You can read the documentation
here:

    http://docs.racket-lang.org/reference/Sandboxed_Evaluation.html

But for any of that documentation to make sense, you may want to first
read the Guide for the reflection and dynamic evaluation section:

    http://docs.racket-lang.org/guide/reflection.html