From: Daniel Martin <martin@...>
Date: 2006-07-28T02:29:53+09:00
Subject: Re: RLisp - Lisp naturally embedded in Ruby

"Tomasz Wegrzanowski" <tomasz.wegrzanowski@gmail.com> writes:

> Can we macro around it or something, so that
> (set-local-variable variable value) introduces a function-local variable
> without increasing indentation level each time it's being done?
>
> I think it's reasonable to write something like that (whatever the names
> of set-local-variable operator is):
>
> (defun veclen (x y)
>  (set-local-variable x2 (* x x))
>  (set-local-variable y2 (* y y))
>  (set-local-variable z2 (+ x2 y2))
>  (sqrt z2)
> )

Well, you can't quite do that but you can easily do something like
this:

(defun veclen (x y)
  (easy-local-progn
    (local x2 (* x x))
    (local y2 (* y y))
    (local z2 (+ x2 y2))
    (sqrt z2)
  )
)

Or:

(defun-with-local veclen (x y)
  (local x2 (* x x))
  (local y2 (* y y))
  (local z2 (+ x2 y2))
  (sqrt z2)
)

(There may also be a way to override the standard meaning of "defun"
to have it do what your "defun-with-local" macro does, but I'd
recommend strongly against overriding standard parts of the language
like that)