[MLton] can mlbasis rename the top-level?

[Stephen Weeks]

> Another thought: we could push even closer to the 'here-document'
> approach and allow the opening/closing delimiters be chosen on a
> per-instance basis.

Is there any reason not to go all the way, start with "<<", specify
the closing terminator after that, and then require the terminator to
start a line?

That is, if we're going this route, why not eliminate all restrictions
on closing delimiter and use a fairly well-known syntax while we're at
it?

I guess this hurts because one could actually have used << as an SML
module-level identifier.  But I've never seen it.  Anyways, we could
choose a different start-of-here-document token but keep the idea of
no restrictions on the terminator.