System queries with Lua: l3sys-query

[Joseph Wright]

Hello all,

Following on from my question about using a Lua based tool with shell
escape, David and I have put together a script for doing (primarily)
directory listings from Lua

https://github.com/latex3/l3sys-query

The aim here is to be able to use it from restricted shell escape, which
means appropriate security review, etc. Hopefully we've been
conservative in that regard (currently it should simply refuse to
provide a listing at all outside pwd). Before thinking about a release,
I'd like to know what we need to do security-wise to have a chance to
get this into the default restricted list.

Regards,

Joseph