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I'd like to export or replicate a scheme environment in another guile process. The algorithm I'm imagining would do something like this to serialize:

(map (lambda (var val) (display (quasiquote (define ,var ,val))
                       (newline))
     (get-current-environment))

And then I'd read/eval that on the other end.

However, while there are functions that return the current environment, they are in some internal format that I can't just map across. How can I "walk" the environment as the above? Alternatively, how else can I replicate an environment into another process?

drysdam
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2 Answers2

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you may decompose the so-called "current-environment" like this:

(define (get-current-binding-list)
        (let* ((e (current-module))  ;; assume checking current-module

               (h (struct-ref e 0))  ;; index 0 is current vars hashtable
              )
       (hash-map->list cons h)  ;; return a vars binding list
    ))

and you can call (get-current-binding-list) to get variables binding list in current-module. Please note that each element in this list is a pair of symbol and variable type, say, (symbol-name . variable-type). So you may print it like this: for a instance ,you got a var binding: 

(define abc 5)

then:

(let ((vl (get-current-binding-list)))
      (assoc-ref vl 'abc)
      )

==> #<variable 9bb5108 value: 5> This result is a "variable type" of variable "abc". You can get it's value with variable-ref procedure.

So you can trace all the bindings and do something ,in your code ,it's simply print var-name and var-value.

I know my answer is too brief, but I think there's enough information to help you to find more details in the manual. Hope this will help you.

NalaGinrut
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  • Awesome answer. Looks like the heart of it is `(current-module)` which may be guile-only, but that's fine. I just want to understand. – drysdam May 03 '11 at 09:58
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You can't really serialize Scheme environment. I don't known even it's possible to (portably) serialize continuations. Oh, and don't forget about FFIs. Ports and threads are unserializable too.

Daniil
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  • Oh yeah, I hadn't thought about ports and such. I don't think I need that for what I'm doing, though. I really just want to replicate variables and functions in another environment to support a kind of RPC. – drysdam May 09 '11 at 12:09