Re: access of global variables from modules

[Neil Jerram]

>>>>> "Peter" == Peter Ivanyi <address@hidden> writes:

    Peter> Hello again,
    Peter> I have another problem with modules.
    Peter> If I have a module can the module access "global" variables.
    Peter> I have an application, which defines some global variables. 
    Peter> The application also loads some modules and I would like to access
    Peter> the global variables from the module. 
    Peter> How can I do it ? (I think I can put the global variables into a 
module
    Peter> and another module can depend on it, but isn't there another way ?)

    Peter> For example I have this module (gen.scm):
    Peter> ----------------------
    Peter> (define-module (gen gen))
    Peter> (export gen-hello)

    Peter> (define (gen-hello)
    Peter>   (set! *G* 3)
    Peter>   (display "Hello World !")
    Peter>   (newline)
    Peter> )
    Peter> -------------------------

What exactly do you mean by a global variable?  Every variable must be
defined in some module, and in this case what you need to do is:

- export *G* from the module in which it is defined

- in (gen gen), `use' that module.

If you say that *G* is global, you probably mean that it is defined in
the (guile-user) module.  So what you need is:

;; ... just after the definition of *G* ...
(export *G*)

;; In gen.scm after the define-module line ...
(use-modules (guile-user))

Please let me know if this helps.

        Neil