or this:

define foo()

! a b

! #!no-sweet

! c d

As written, it sounds that the directives must have a flat, global effect on the port, crossing all ( ) boundaries.

But correctly implementing this sounds painful to me.  E.g. you can't call a lower-level (read) / (neoteric-read) unless they understand these directives.  And every procedure must be ready for sweet processing to be turned off underneath it.

I propose for simplicity to say that these directives SHOULD (MUST?) be used only at top level.

Probably also require them to be alone on a line, at column 0 (trailing hspace and comments are ok)?