Re: Add partial :-variable expansion to psql \copy

Re: Fabien Coelho
> (1) it seems that is the only command which is really full SQL hidden in a
> backslash command

Perhaps this form could be improved by changing `\copy (select) to file`
to something like `select \gcopy (to file)`. That might make :expansion
in the "select" part easier to handle.

I've heard several complaints that `\copy (select)` can't be wrapped
over several lines, so offering the alternative syntax in parallel to
\copy would also solve another problem.

Christoph