reverse in Emacs 24.4

reverse in Emacs 24.4

[Nicolas Petton]

Hi,

Some functions of seq.el require reverse to work with sequences, not
only lists as it is in Emacs 24.4.

Currently, `seq-reverse' is an alias for `reverse'.

I want to add a backward-compatible version `seq-reverse' for older
versions of Emacs, but I'm not sure how I should check the version of
Emacs.  Parsing the string `emacs-version' seems like a bad idea.

Any advice?

Cheers,
Nico
-- 
Nicolas Petton
http://nicolas-petton.fr

Re: reverse in Emacs 24.4

[Artur Malabarba]

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> versions of Emacs, but I'm not sure how I should check the version of
> Emacs.  Parsing the string `emacs-version' seems like a bad idea.

By "parsing", do you mean version<?

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Re: reverse in Emacs 24.4

[Nicolas Petton]

Artur Malabarba <bruce.connor.am@gmail.com> writes:

>> versions of Emacs, but I'm not sure how I should check the version of
>> Emacs.  Parsing the string `emacs-version' seems like a bad idea.
>
> By "parsing", do you mean version<?

No, I didn't know about this functions, thanks!

Nico
-- 
Nicolas Petton
http://nicolas-petton.fr

Re: reverse in Emacs 24.4

[Stefan Monnier]

> I want to add a backward-compatible version `seq-reverse' for older
> versions of Emacs, but I'm not sure how I should check the version of
> Emacs.  Parsing the string `emacs-version' seems like a bad idea.

The way I usually "parse" versions looks like:

   (defalias 'seq-reverse
      (if (ignore-errors (reverse [1 2]))
          #'reverse
        (lambda ...)))


-- Stefan

Re: reverse in Emacs 24.4

[Nicolas Petton]

Stefan Monnier <monnier@IRO.UMontreal.CA> writes:

>> I want to add a backward-compatible version `seq-reverse' for older
>> versions of Emacs, but I'm not sure how I should check the version of
>> Emacs.  Parsing the string `emacs-version' seems like a bad idea.
>
> The way I usually "parse" versions looks like:
>
>    (defalias 'seq-reverse
>       (if (ignore-errors (reverse [1 2]))
>           #'reverse
>         (lambda ...)))

I see.  So you'd rather test the feature instead of check the version of
Emacs?

Nico
-- 
Nicolas Petton
http://nicolas-petton.fr

Re: reverse in Emacs 24.4

[Stefan Monnier]

> I see.  So you'd rather test the feature instead of check the version of
> Emacs?

Yes,


        Stefan

Re: reverse in Emacs 24.4

[Stephen J. Turnbull]

Stefan Monnier writes:

 > > I see.  So you'd rather test the feature instead of check the version of
 > > Emacs?
 > 
 > Yes,

It's more reliable (it works with branches that may have the patch but
not an updated emacs-version), and Emacs Lisp is implemented by other
projects that don't follow Emacs versioning.

Re: reverse in Emacs 24.4

[Stefan Monnier]

> Emacs Lisp is implemented by other projects that don't follow
> Emacs versioning.

Are you talking about Sam Steingold's "Elisp in Common-Lisp"?


        Stefan ;-)