Installing cond* in core

[Stefan Kangas]

Hi emacs-devel,

After careful consideration and off-line discussions between Eli and
myself, we have come up with the following proposed plan:

 1. We will install cond* in core and let people who prefer it use it,
    while people who prefer pcase are free to keep using pcase.

 2. cond* vs pcase is to be considered a matter of stylistic preference.

 3. There is no intention to forcibly replace pcase with cond* in our
    code.

Everyone will be free to maintain the code that falls within their area
of responsibility using the style that they like best.  We hope that
this will make sense to proponents of both sides of the argument.

I have myself expressed significant reservations about installing cond*
in core.  The above could be seen as a politicians response to a
technical problem, and to some extent it is.

Our responsibility as maintainers is first and foremost to ensure that
we can all work together, and unite under a common banner.  Our success
as a project depends on it.  Thus, the last thing we want to do is to
alienate any group of contributors, big or small.

We believe that this is a more important concern than the arguments for
or against cond* or pcase.  The simple fact is that we have different
backgrounds and experiences, which have tended to land us on either side
of this discussion.  This diversity is a strength, and not a weakness.

However, the strong emotions and significant differences of personal
preferences between several very active contributors over months of
discussions have not left us with many reasonable choices.

Note that this decision does not throw our basic coding guidelines out
the window: we will still try to respect the local style of files we
change, the maintainers of various files typically have final say, etc.

It also goes without saying that it's probably best if the proposed
improvements to cond* are considered before the macro is installed.
It is our understanding that Richard intends to work on that.

Finally, this co-maintainer would like to draw everyone's attention to
this paragraph in a recent article[1] on sharp technical divisions over
typing in the Python community:

    The discussion highlighted another thing that is something of a
    hallmark of the Python world: cordiality even in the face of strong
    disagreement ...  Python conversations are almost always
    collegial—and have been for decades.  For example, several took the
    opportunity of the thread to thank the typing developers and to
    recognize that the feature does have uses (and users), even if they
    were not particularly inclined toward using typing themselves.  It
    all helps reinforce Brett Cannon's adage that he came for the
    language, but stayed for the community.  It also bodes well for
    finding reasonable solutions and compromises for typing—and more.

If it is true that Python "can be seen as a dialect of Lisp with
'traditional' syntax",[2] then perhaps it is our turn to take a cue
from them.


Footnotes:
[1]  https://lwn.net/Articles/958326/

[2]  https://norvig.com/python-lisp.html