Re: using setq to create lists based on other lists...

[Jean-Christophe Helary <brandelune@gmail.com>]

> On Dec 3, 2018, at 0:07, Stefan Monnier <monnier@iro.umontreal.ca> wrote:
> 
> Here's another take on it:
> 
>> If you do
>> (setcar list0 0)
> 
> Why?  Just don't use setcar/setcdr!

Lovely :)

When I check "Modifying Existing List Structure" the only things I find of any use in my case are setcar/setcdr.

>> There are probably better ways to create lists based on other lists without
>> "linking" the two, so I'd like some information about that.
> 
> The better way is to not modify the lists, so you're not affected by
> whether they're linked or not.

I would certainly have considered that if I had known that setq was linking the lists :)

And I'm sure the code I wrote is laughable, because there are probably thousands of more idiomatic ways to write what I want to achieve, but if there had been just a footnote about setq linking lists, I certainly would not have spent the day on that :)


Jean-Christophe Helary
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http://mac4translators.blogspot.com @brandelune