[Chicken-users] Nifty finalizer-related macro

[Ed Watkeys]

Hey,

Until I figure out* how to use C_do_register_finalizer(...), I've got 
to wrap a bunch of foreign functions that return pointers so that a 
finalizer is installed. The enlightened lazy person in me first thought 
to write a function:

(define (make-finalizing proc finalizer)
  (lambda args
    (let ((result (apply proc args)))
      (set-finalizer! result finalizer))))

With it, you can write the following:

(define make-thing
  (make-finalizing
    make-thing-in-c
    finalize-thing))

Yeah, that was good, but the really lazy person in me said, "Hey, you 
can do better; don't make me work!" So I thought for a bit and came up 
with this:

(define-macro (define-finalizing name proc finalizer)
  `(define (,name . args)
     (let ((result (apply ,proc args)))
       (set-finalizer! result ,finalizer)
       result)))

With this macro, you can now type a little less:

(define-finalizing
  make-thing
  make-thing-in-c
  finalize-thing)

I don't know if this will be useful to anyone, but given that I'm going 
to implement glue to a large-ish API three times, I'm looking to save 
keystrokes wherever possible.

Regards,
Ed

* I've already asked too many questions today.
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Watkeys Product Design -- http://watkeys.com/