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newLISP Fan Club

Forum => Anything else we might add? => Topic started by: Dmi on November 18, 2005, 02:12:47 PM

Title: keyword parameters
Post by: Dmi on November 18, 2005, 02:12:47 PM
I experiment with keyword arguments. Like :key in common lisp.
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(define-macro (keyfun _fn)
  (eval (append '(let) (list _args) _fn)))

(define (add-two)
  (let (_args (args))
    (keyfun
      (println (+ first-val second-val)))))

so:
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newLISP v.8.7.0 on linux, execute 'newlisp -h' for more info.

> (add-two 'first-val 1 'second-val 2)
3

This makes possible constructs like:
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(send-email
  'from "me@here"
  'to "you@there"
  'body (format-message....))

(I reproduce some lisp example)



But can the syntax be more clear?

Something like:
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(define (add-two)
  (keyfun body))

or even:

(define-keyfun (fun-name) (fun-body))
Title:
Post by: Dmi on November 19, 2005, 03:14:27 AM
I was quite stupit yesterday... it's simple!
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(define-macro (keyfun)
  (eval (append '(let) (list _args) (args))))

(define-macro (define-keyfun _fnh)
  (set (_fnh 0)
       (append '(lambda) (list (1 _fnh))
               (list (append '(let (_args (args)))
                       (list (append '(keyfun) (args))))))))

(define-keyfun (test-val val)
  (print "testing " val " against " against "...")
  (println (unless (= val against) " not" "") " match"))

(test-val 1 'against 2)
Title:
Post by: Fanda on November 19, 2005, 10:48:09 AM
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; This solution doesn't hide the implementation details. Good or bad?

(define (test)
  (let (x nil y nil)
    (apply set (args))
    (println "x = " x " y = " y)))


(test 'x 1 'y 2)  ; => x = 1 y = 2
(test 'y 2 'x 1)  ; => x = 1 y = 2


Fanda
Title:
Post by: Dmi on November 19, 2005, 10:53:50 AM
Yes! It's that I really looking for :-)

Thanks.
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