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Re: Evaluation of macro arguments
From: |
Marcin Borkowski |
Subject: |
Re: Evaluation of macro arguments |
Date: |
Tue, 05 Jan 2016 20:39:28 +0100 |
User-agent: |
mu4e 0.9.13; emacs 25.1.50.1 |
On 2016-01-05, at 20:22, Pascal J. Bourguignon <pjb@informatimago.com> wrote:
> Marcin Borkowski <mbork@mbork.pl> writes:
>
>> Hi all,
>>
>> continuing my quest to grok macro argument evaluation issues, I'd like
>> (again) to make sure that I get it correctly. So I have this simple
>> macro generating a list of consecutive numbers (which is not without
>> problems - I am aware of those, namely (i) it uses hard-coded symbols
>> instead of generating them on the fly, and (ii) it has no error
>> checking):
>>
>> (defmacro range (from dir to)
>> `(let ((delta (cond ((eq ',dir 'upto) 1)
>> ((eq ',dir 'downto) -1)))
>> (i ,from)
>> (list nil))
>> (while (not (= i ,to))
>> (push i list)
>> (setq i (+ i delta)))
>> (nreverse list)))
>
> (let ((i 0))
> (list (range i 'upto (incf i 10)) ; bam!
> i))
>
> I hope you may debug it well.
That's unfair, Pascal; I wrote that I'm aware of this, I know how to
make it work, and wasn't asking about it.
Best,
--
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University
Re: Evaluation of macro arguments, Pascal J. Bourguignon, 2016/01/05
- Re: Evaluation of macro arguments,
Marcin Borkowski <=