(without-interrupts (with-interrupts ...))

[Robert W. Kerns <RWK at MIT-MC>]

I do not agree that this is an ill-formed notion.

Consider:

(without-interrupts  ;;don't interrupt until we're ready
  (do () (())        ;;DO-FOREVER
    (do-some-interrupt-critical-=stuff)
    (do-some-more-stuff)
    (if unusual-state (with-interrupts (interact-with-user)))))

WITHOUT-INTERRUPTS says we can't allow interrupts to happen at
indiscriminate points within the form.  However, there may well
be points at which we do know interrupts are OK, and very likely
will be highly desirable.  WITHOUT-INTERRUPTS and WITH-INTERRUPTS,
used together, provide an generalization of polling for interrupts.