Re: modules

[Andreas Rottmann]

Ian Zimmerman <address@hidden> writes:

> 1/ How can I customize a module during loading?  In Emacs Lisp, 
> I can either:
>
> a) set a global variable, for instance 
>
> (setq foo-module:bar 'baz)
>
> prior to loading a library "foo-module".  If that library itself does
>
> (defvar foo-module:bar)
>
> it picks up the value that was previously set.  But in Scheme, set! only
> works on variables that have already been define'd, and a define creates
> a new variable totally unrelated to the existing value.
>
What exactly do you want to accomplish? The point of modules is to
isolate mostly independent code from each other, and using a global
variable would just prevent that isolation. If you need a global
module setting, you can provide accessor functions:

(define *bar* "The bar")

(define (set-bar! val)
  (set! *bar* val))

(define (get-bar)
  *bar)

Andy
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