TRANSFORM = s,x,x,

TRANSFORM = s,x,x,

[Hongyi Zhao]

In the Makefile of Emacs, there is the following code:

# Program name transformation.
TRANSFORM = s,x,x,

But I really can't figure out the effect of this transformation, as
shown in the following example:

$ echo emacs-29.0.50 | sed 's,x,x,'
emacs-29.0.50

As you can see, this transformation does nothing.

Any hints for this problem?

Regards,
-- 
Assoc. Prof. Hongyi Zhao <hongyi.zhao@gmail.com>
Theory and Simulation of Materials
Hebei Vocational University of Technology and Engineering
No. 473, Quannan West Street, Xindu District, Xingtai, Hebei province

Re: TRANSFORM = s,x,x,

[Kévin Le Gouguec]

Hongyi Zhao <hongyi.zhao@gmail.com> writes:

> Any hints for this problem?

Not sure about actual use-cases, but if you dig into Makefile.in, you'll
see that TRANSFORM is set from program_transform_name.  Jumping into the
configure script, this seems to be set only when --program-prefix or
--program-suffix are provided.

No idea if this is generic autotools stuff, and/or if this is relevant
to Emacs 🤷

Re: TRANSFORM = s,x,x,

[Stephen Berman]

On Sun, 14 Nov 2021 09:52:48 +0100 Kévin Le Gouguec <kevin.legouguec@gmail.com> wrote:

> Hongyi Zhao <hongyi.zhao@gmail.com> writes:
>
>> Any hints for this problem?
>
> Not sure about actual use-cases, but if you dig into Makefile.in, you'll
> see that TRANSFORM is set from program_transform_name.  Jumping into the
> configure script, this seems to be set only when --program-prefix or
> --program-suffix are provided.
>
> No idea if this is generic autotools stuff, and/or if this is relevant
> to Emacs 🤷

It's from autoconf and seems to be intended for cross-compilation and
installing multiple versions, see e.g. https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.70/html_node/Transforming-Names.html#Transforming-Names

Steve Berman

Re: TRANSFORM = s,x,x,

[Stefan Monnier via Users list for the GNU Emacs text editor]

Hongyi Zhao [2021-11-14 08:32:22] wrote:
> In the Makefile of Emacs, there is the following code:
> # Program name transformation.
> TRANSFORM = s,x,x,
>
> But I really can't figure out the effect of this transformation, as

It's intended to do nothing, but it allows to perform a rewriting by
overriding the value of TRANSFORM.


        Stefan

Re: TRANSFORM = s,x,x,

[Hongyi Zhao]

On Sun, Nov 14, 2021 at 4:52 PM Kévin Le Gouguec
<kevin.legouguec@gmail.com> wrote:
>
> Hongyi Zhao <hongyi.zhao@gmail.com> writes:
>
> > Any hints for this problem?
>
> Not sure about actual use-cases, but if you dig into Makefile.in, you'll
> see that TRANSFORM is set from program_transform_name.  Jumping into the
> configure script, this seems to be set only when --program-prefix or
> --program-suffix are provided.

I confirmed your statement with the following supplementary information:

emacs.git$ rg -A1 -uu  'test.*program_(pre|suf)fix'  configure
4352:test "$program_prefix" != NONE &&
4353-  program_transform_name="s&^&$program_prefix&;$program_transform_name"
--
4355:test "$program_suffix" != NONE &&
4356-  program_transform_name="s&\$&$program_suffix&;$program_transform_name"


> No idea if this is generic autotools stuff, and/or if this is relevant
> to Emacs 🤷