[graphic-forms-devel] Dialogs return values

[Jack Unrue]

On 3/25/07, Edgar Gonçalves <edgar.goncalves at gmail.com> wrote:
>
> Hi! I've just started playing with graphic-forms, and I wanted to
> build some macros to generate message-boxes (which I did based on your
> demo about-dialog), and some input-prompts, like Yes/No questions, or
> a simple OK/Cancel. But I'm not figuring how I can set a return value
> for such functions (they seem to return the value 4 once (gfw:show dlg
> t) is called). Right now I managed a dirty hack by placing a global
> variable and making the dialog change it. but this is not as
> functional as I would want... Any suggestions?
>

Hi Edgar. Your macros could be written to establish a lexical binding
and then use a closure as a callback for each widget in the dialolg.
Or you could define a new dispatcher class and specify that for each
widget, with one or more slots carrying important return info. You
might consider constructing your macros such that the user of the
macro provides one or more symbols to identify bindings whose values
are to carry whatever result info your dialogs will provide, which can
then be accessed within the body of the macro. The WITH-* macros
for the color, file, and font dialogs work this way.

The exact return value of GFW:SHOW is whatever the underlying
window system returns -- I might change the function to return (values)
just to emphasize that it's not a value that the application can use.
But you could obviously implement a wrapper around GFW:SHOW if
you wanted a function-based API.

-- 
Jack Unrue