Re: Why is there no `until' in elisp?

[Eric Abrahamsen <eric@ericabrahamsen.net>]

"Garreau, Alexandre" <galex-713@galex-713.eu> writes:

> On 2018-10-16 at 12:16, Eric Abrahamsen wrote:
>> "Garreau, Alexandre" <galex-713@galex-713.eu> writes:
>>> [0] such as: (defmacro until (test &rest body) (declare (indent 1))
>>> `(while (not ,test) ,@body))
>>
>> I have nothing to do with this, but my feeling is that Lisp developers
>> in general drag their feet about adding trivial/obvious constructs to
>> the standard library.
>
> Why?  If this is because of the triviality of reimplementing, wouldn’t
> they do, once they want to use it in contributing emacs (I keep seeing
> many (while (not …) …))?  or do they restrain themselves for some
> rational/useful reason I still ignore?
>
> The “it’s one macro more to learn fully the language” doesn’t stand that
> much (especially about elisp) to me as it is easy to read source code,
> easy to find definitions, and “unless” is as much an english word as
> “while” (maybe even more widespread, outside of programming).

Again, I'm not one of these developers, so I'm putting words in others'
mouths...

I don't think it has anything to do with making the language harder to
learn. It's just the fact that the constructs are so easy to add (this
is the power of lisp, after all), and different developers might want
very slightly different versions of the same thing, so people just put
in their own versions of things.

Obviously there are plenty of people who feel differently about it,
which is why we have all these supplementary packages within Emacs and
the package repositories.

But the core of the language remains conservative about additions.
Personally, I think that's a good thing.

Eric