Eduardo Cavazos <[email protected]> writes:
> The (glamour mouse) library has a few macros for working with the mouse:
>
> http://github.com/dharmatech/agave/raw/master/glamour/mouse.sls
>
> These work great in a script where everything is defined at the "top
> level". However, notice something; each macro expands into definitions
> followed by non-definition statements. This means that if you want to
> setup a demo inside of a scope (this easily comes up when you want
> multiple windows running in the same Scheme instance) then you have to
> do things like this:
>
[code snipped]
> I.e. put each macro at the top of a new 'let' body.
>
> I thought it would be neat to have macros which work and look nice
> when used at the top level as well as inside 'define' and 'let'
> bodies. But perhaps the way glut is designed prevents a
> straightforward path to this.
>
> Suggestions welcome!
>
What I do in these cases (I have run into this problem several times as
well), is make the macro expand into a series of definitions only, using
a dummy definition around the expresssions, like this:
(define dummy
(begin
(some-expr)
(and-another)
'dummy-val))
Because this is ugly, I use define-values to hide (some of) the
boilerplate, making it somewhat nicer:
(define-values ()
(some-expr)
(and-another))
That will expand to pretty much the previous example; at least with the
define-values implementation I'm using (which ignores the values
returned by the body if the list of defined identifiers is empty).
Regards, Rotty
