*Arc is still a work in progress. [...] it's
still in the semi-finished state most software
is, full of hacks and note-to-self comments about
fixing them.*
It's good to know that the principle of invoking arc as a script-runner isn't excluded.
Maybe you changed the tuto since that, but if not, see: http://www.arclanguage.org/item?id=9875 (that was 47 ago, on a thread when you announced new features to arc3.tar, which was then "fairly recent").
I find them quite useful for my irc bot, although I do run into the problem of not being able to @-substitute a simple variable unless it's going to be followed by something not permissible in a symbol. In particular, colons will be parsed as part of the symbol, which is a PITA. There is a workaround for this, but it's ugly: