Have you considered using this kind of macro:
#lang racket
(define-syntax ==>
(syntax-rules ()
[(_ (it) one) one]
[(_ (it) one two ...) (let ((it one)) (==> (it) two ...))]))
(==> (it) (+ 1 1) (+ it 1) (+ it it))
(define mult *)
(==> (it) (* 1 1) (* it 1) (* it it))
On Feb 12, 2012, at 3:09 PM, FS Racket wrote:
>
>
> On Sun, Feb 12, 2012 at 1:34 PM, Richard Cleis <[email protected]> wrote:
> The DrRacket interactions window replies with 48, not an error, when your
> syntax is defined in the definitions window, your function is defined in the
> interactions area, and the example is finally run in the interactions area.
>
> How are you making it fail?
>
> Also, have you attempted to use the Macro Stepper? Even if you aren't
> actually debugging the macro, it coerces you to organize your thoughts about
> how your code is organized (in this case, how the expansion relates to the
> word 'mult' and it's actual definition.)
>
> rac
>
>
> Hi Richard,
>
> Good questions.
>
> The way my code is organized is that the macro is in its own file and
> installed as a collection in my personal library (i.e. the default location
> of personal collections). I then create a new file, say "test.rkt", require
> the macro library file, and then define the function "mult". Within this
> same file, I then add the code examples contained in my previous email.
> Finally, I "run" the "test.rkt" file using the "Racket -> Run" menu option.
>
> Yes, I have used the macro stepper; I should have mentioned that. It's
> bizarre. Prior to any expansion, all identifiers named 'mult' have an
> associated binding. As I step through the expansion in the following code,
> the last 'mult' eventually loses its binding. I don't know how or why.
>
> (==>
> (mult 12 2)
> (mult 2 _)
> (mult _ 1))
>
> Please let me know if any further clarification is needed.
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