How check when symbol is introduced in Emacs?

How check when symbol is introduced in Emacs?

[Oleksandr Gavenko]

Usually I get Error with previous Emacs version when symbol is undefined.

To workaround I use code like:

(when (or (>= emacs-major-version 23)
                   (and (= emacs-major-version 22) (>= 
emacs-minor-version 2)))
    (setq 'symb val)
   )

But I must know low limit of version to get better code.

Previously I put version when Emacs don;t fail.

Next I learn to search ChangeLog.

Next I learn use bzr repo with C-x v g and pressing a lot of 'A' command but
it to hard understand which revision goes to release.

Some symbol have properties like :version "20.4". I use it.

Please recommend another simple way or point to docs!

Re: How check when symbol is introduced in Emacs?

[suvayu ali]

On Wed, Jan 19, 2011 at 11:23 AM, Oleksandr Gavenko
<gavenko@bifit.com.ua> wrote:
> Next I learn use bzr repo with C-x v g and pressing a lot of 'A' command but
> it to hard understand which revision goes to release.
>

If you have a git mirror of the emacs repo,

$ git log -S'<symbol_name>' --graph --oneline | tail -1

should give you the first ever commit which introduces a line with the
symbol name.

-- 
Suvayu

Open source is the future. It sets us free.

Re: How check when symbol is introduced in Emacs?

[Eli Zaretskii]

> From: Oleksandr Gavenko <gavenko@bifit.com.ua>
> Date: Wed, 19 Jan 2011 12:23:59 +0200
> 
> Usually I get Error with previous Emacs version when symbol is undefined.
> 
> To workaround I use code like:
> 
> (when (or (>= emacs-major-version 23)
>                    (and (= emacs-major-version 22) (>= 
> emacs-minor-version 2)))
>     (setq 'symb val)
>    )
> 
> But I must know low limit of version to get better code.

Why not use `boundp'?

Re: How check when symbol is introduced in Emacs?

[Oleksandr Gavenko]

On 19.01.2011 17:19, Eli Zaretskii wrote:
>> From: Oleksandr Gavenko<gavenko@bifit.com.ua>
>> Date: Wed, 19 Jan 2011 12:23:59 +0200
>>
>> Usually I get Error with previous Emacs version when symbol is undefined.
>>
>> To workaround I use code like:
>>
>> (when (or (>= emacs-major-version 23)
>>                     (and (= emacs-major-version 22) (>=
>> emacs-minor-version 2)))
>>      (setq 'symb val)
>>     )
>>
>> But I must know low limit of version to get better code.
>
> Why not use `boundp'?
>
This is interesting tips. I already use this but not always.

Re: How check when symbol is introduced in Emacs?

[Stefan Monnier]

> Usually I get Error with previous Emacs version when symbol is undefined.

> To workaround I use code like:

> (when (or (>= emacs-major-version 23)
>                   (and (= emacs-major-version 22) (>= emacs-minor-version
> 2)))
>    (setq 'symb val)
>   )

Bad idea: rather than worry about which Emacs started to provide this
variable, stick to your real problem, which is to figure out whether
your currently running Emacs provides it.  And that's easy to do:

   (boundp '<symbol>)

will tell you just that.  If you want to test the presence of
a function, you can similarly use (fboundp '<symbol>).
   

        Stefan