Was moving (set!) into the (%bind) form, and thus setting the wrong variable.
Now, if set! var is bound, will create a temporary for result of %bind first,
and set! original variable to temporary in the proper scope.
Also, normalize rules for nested (%bind)s:
* The (%bind) inside a (%lambda) is always flat.
- This is a responsiblity of simplify-lambda, and any function which
may change structure after simplification (e.g. promote-to-box).
* Any other (%bind) may be nested, unless otherwise noted.
Also:
- assume top-level free variables are constants, not boxes;
- bind variable 'argv' to top-level argument list, rather than assuming no arguments;
- make %values a first-class form, just like %apply and %call/cc (was: pseudo-primitive);
- fix case where 'rest' argument is sole item in argument list: (lambda argv ...); and
- perform misc. cleanup in output code.
Also performed misc. cleanup, corrected use of temp variables in (let ...),
changed make-bindings-unique to preserve original names as prefixes, improved
detection of unused %set! forms in reduce-set!, and fixed map-variables to
extract the real value from (quote ...) literal forms.
With this change, any (%bind) returned from (simplify-let) or (simplify-form)
can be assumed to be flat, with unique bound symbols. Before, this was only
true of (%lambda) forms and the output of (compile).
Exception is (%tail-call ...) form, which is permitted simply because
(%tail-call ...) transfers control unidirectionally; the enclosing
(%set! ...) form wouldn't be run anyway.
Jesse D. McDonald