grep-changelog in the emacs distro

grep-changelog in the emacs distro

[Randal L. Schwartz]

'grep-changelog' is apparently the *only* thing in the current emacs HEAD
that requires Perl.

Would it be possible to put its build and install behind a configure
switch so that a variant of Emacs might be built and packaged that does
*not* require Perl?

(Yes, this is an odd thing for me to ask, but a co-worker is asking...,
and as the Perl expert, I'd like to know.)

-- 
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
<merlyn@stonehenge.com> <URL:http://www.stonehenge.com/merlyn/>
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Re: grep-changelog in the emacs distro

[Chong Yidong]

merlyn@stonehenge.com (Randal L. Schwartz) writes:

> 'grep-changelog' is apparently the *only* thing in the current emacs HEAD
> that requires Perl.
>
> Would it be possible to put its build and install behind a configure
> switch so that a variant of Emacs might be built and packaged that does
> *not* require Perl?

AFAICT, grep-changelog is installed simply by copying into the install
directory; Perl isn't required or that.  And it's not used by any other
part of Emacs either.

Re: grep-changelog in the emacs distro

[Ulrich Mueller]

>>>>> On Tue, 03 Jan 2012, Randal L Schwartz wrote:

> 'grep-changelog' is apparently the *only* thing in the current emacs
> HEAD that requires Perl.

AFAICS, Perl isn't required at build time, but only for running the
grep-changelog script.

> Would it be possible to put its build and install behind a configure
> switch so that a variant of Emacs might be built and packaged that
> does *not* require Perl?

We've had similar discussions in Gentoo, and the conclusion was that
doing such things isn't feasible.

Emacs relies on several external programs. They're kind of "soft"
dependencies which are required to perform various functions at
runtime.

So, if you take the road of removing grep-changelog if there's no
Perl, then you should also remove other parts of Emacs if other
programs are absent. For example, you'd have to remove tramp if
there's no ftp, ssh, or sudo. ispell.el requires some spell checker.
Functions for printing don't work if there's no print system (like
cups or lpr) installed. vc*.el needs some version control system.

Also, what are you going to do if Perl is installed on the system at
a later time? You'd have to rebuild Emacs in that case.

Ulrich

Re: grep-changelog in the emacs distro

[Michael Albinus]

Ulrich Mueller <ulm@gentoo.org> writes:

> So, if you take the road of removing grep-changelog if there's no
> Perl, then you should also remove other parts of Emacs if other
> programs are absent. For example, you'd have to remove tramp if
> there's no ftp, ssh, or sudo.

I basically agree with your message about dependencies, but in the Tramp
case it isn't precise. There are several alternative access methods for
Tramp, if the quoted ones are not available.

(progn
  (require 'tramp)
  (message "%s" (mapcar 'car tramp-methods)))

Just my 2c :-)

> Ulrich

Best regards, Michael.