[r6rs-discuss] [Formal] eliminate library export immutability loophole

[R. Kent Dybvig]

> I'm thinking that the "once-only" restriction should apply to top-level
> definitions and expressions as well.  Am I correct?

If you mean "top-level program definitions and expressions", yes, or at
least almost.  The once-only would be implied (by the mechanism for
converting top-level programs to libraries) for the definitions of a
top-level program and for expressions that come before the definitions. 
The once-only is not implied and not necessary for the expressions that
follow all definitions.

Kent