Bug?: (file-name-extension "some.html~") gives "html"

Bug?: (file-name-extension "some.html~") gives "html"

[Lennart Borgman]

Is the behaviour in the subject line correct? I have tested this on w32:

GNU Emacs 22.0.50.1 (i386-mingw-nt5.0.2195) of 2006-05-01

If this is the correct behaviour then maybe the docstring should tell 
about it?

Re: Bug?: (file-name-extension "some.html~") gives "html"

[Kevin Rodgers]

Lennart Borgman wrote:
> Is the behaviour in the subject line correct? I have tested this on w32:
> 
> GNU Emacs 22.0.50.1 (i386-mingw-nt5.0.2195) of 2006-05-01
> 
> If this is the correct behaviour then maybe the docstring should tell 
> about it?

It is correct (file-name-extension calls file-name-sans-versions
before looking for the extension), and it should be documented.

-- 
Kevin

Re: Bug?: (file-name-extension "some.html~") gives "html"

[Luc Teirlinck]

Lennart Borgman wrote:

   Is the behaviour in the subject line correct? I have tested this on w32:

   GNU Emacs 22.0.50.1 (i386-mingw-nt5.0.2195) of 2006-05-01

   If this is the correct behaviour then maybe the docstring should tell 
   about it?

Yes, it is documented in the Elisp manual (but not in the docstring).
>From `(elisp)File Name Components':

 -- Function: file-name-extension filename &optional period
     This function returns FILENAME's final "extension", if any, after
     applying `file-name-sans-versions' to remove any version/backup
     part.

Sincerely,

Luc.

Re: Bug?: (file-name-extension "some.html~") gives "html"

[Lennart Borgman]

Luc Teirlinck wrote:
> Lennart Borgman wrote:
>
>    Is the behaviour in the subject line correct? I have tested this on w32:
>
>    GNU Emacs 22.0.50.1 (i386-mingw-nt5.0.2195) of 2006-05-01
>
>    If this is the correct behaviour then maybe the docstring should tell 
>    about it?
>
> Yes, it is documented in the Elisp manual (but not in the docstring).
> >From `(elisp)File Name Components':
>
>  -- Function: file-name-extension filename &optional period
>      This function returns FILENAME's final "extension", if any, after
>      applying `file-name-sans-versions' to remove any version/backup
>      part.
>
> Sincerely,
>
> Luc.
>   
Then maybe a line saying something like

    This function removes any version/backup parts in the file name first.

could be added to the doc string?

Re: Bug?: (file-name-extension "some.html~") gives "html"

[Kevin Rodgers]

Lennart Borgman wrote:
> Luc Teirlinck wrote:
>> Yes, it is documented in the Elisp manual (but not in the docstring).
>> >From `(elisp)File Name Components':
>>
>>  -- Function: file-name-extension filename &optional period
>>      This function returns FILENAME's final "extension", if any, after
>>      applying `file-name-sans-versions' to remove any version/backup
>>      part.
>
> Then maybe a line saying something like
> 
>    This function removes any version/backup parts in the file name first.
> 
> could be added to the doc string?

If so, file-name-sans-extension should get the same treatment, for the
same reason.

BTW, why does file-name-extension accept an optional PERIOD argument
to include the extension delimiter in the result, but
file-name-sans-extension does not?

Symmetry baby,
-- 
Kevin

Re: Bug?: (file-name-extension "some.html~") gives "html"

[Andreas Schwab]

Kevin Rodgers <ihs_4664@yahoo.com> writes:

> BTW, why does file-name-extension accept an optional PERIOD argument
> to include the extension delimiter in the result, but
> file-name-sans-extension does not?

I don't think there is a need to cut off the extension while keeping the
period, whereas keeping the period together with the extension is quite
common.

> Symmetry baby,

This is asymmetric in nature.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
PGP key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: Bug?: (file-name-extension "some.html~") gives "html"

[Kevin Rodgers]

Andreas Schwab wrote:
> Kevin Rodgers <ihs_4664@yahoo.com> writes:
> 
>> BTW, why does file-name-extension accept an optional PERIOD argument
>> to include the extension delimiter in the result, but
>> file-name-sans-extension does not?
> 
> I don't think there is a need to cut off the extension while keeping the
> period, whereas keeping the period together with the extension is quite
> common.

I suppose that the utility of keeping the period with the extension is
to allow it to be appended to some other extension-less file name.  And
likewise the utility of keeping the period with the file name would be
to allow some extension to be appended to it.

>> Symmetry baby,
> 
> This is asymmetric in nature.

I guess it depends on your perspective.  I see the file name base and
extension as symmetric components on either side of the period.

-- 
Kevin

Re: Bug?: (file-name-extension "some.html~") gives "html"

[Richard Stallman]

It is intentional.  I will document it.