I'm trying to fix a problem in pandoc (see
https://github.com/jgm/pandoc/pull/1589) where it doesn't properly sanitize
the reference labels in ConTeXt output, causing errors during compilation
when a label contains '#' for example. Note that this sanitizing is needed
in addition to the regular backslash escaping used for control characters:
'\#' is still illegal in a label for example.

In the sanitizer function I'm writing, I'd like to properly escape all
illegal characters, but I couldn't find an explicit list of allowed or
illegal characters. Based on some testing I've conducted (see attached
file), I've arrived at the following set:

\#[]",{}%()|=

1) Does this look like a reasonable set? Are there other characters or
sequences that should be included, or are worth testing?

2) I was told (see
https://groups.google.com/forum/#!topic/pandoc-discuss/tYpXMUkmbEY) that if
the characters " and , didn't work, it would count as a ConTeXt bug, is
there any truth to that? Please let me know if any further info is needed
on my part.

3) Does anyone see issues with this general approach? I'm relatively new to
ConTeXt, so I might be missing either a huge problem, or an obviously
easier way to do this.

Thanks,

Mark