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Re: member returns list


From: Pascal J. Bourguignon
Subject: Re: member returns list
Date: Mon, 07 Sep 2015 01:47:47 +0200
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux)

Emanuel Berg <embe8573@student.uu.se> writes:

> "Pascal J. Bourguignon" <pjb@informatimago.com>
> writes:
>
>> Because each implementation worked on a different
>> machine with a different OS (if an OS was available
>> at all).
>
> Yeah, but there were many machines at the time of the
> "crazy language" C as well, still, there aren't
> a plethora of C dialects. (If you don't count all the
> epigone languages that borrowed heavily the syntax
> of C.)
>
> But C is famous for its portability (which also
> proliferated Unix) - perhaps the exception that
> confirms the rule, that Lisp is cooler than C?

It's not exactly the same time period, and not the same kind of
machines.

Basically, C was running on small machines, that were all the same.
After C the micro-processors appeared, and since they were so bad, they
soon were optimized to run C code efficiently.

On the other hand, Lisp was running on mainframes, each with a different
kind of processor.  Those were machines that could get new instructions
each week!

Granted, the CADR was a prototype:
https://c1.staticflickr.com/5/4040/4456481460_e7ef34f49e_b.jpg
so it wouldn't be surprising if it got new instructions hardwired often.
But it was also the case on other mainframe, commercially
installed.  They got upgrades that changed the instructions.


Also, a variant of what has already been discussed to death, C syntax is
so horrible than you don't dare implement a new parser: you get the
grammar from some previous compiler, and you use a parser generator to
parse the same.  On the other hand, there's no parser in lisp, and you
can implement a lisp reader in half a hour.  You can implement a running
lisp system in an afternoon (remember, EVAL is one page in AIM-8).

Basically, you can implement a lisp without having access to an old lisp
system, just by hearing about it and having a little light bulb going
tilt in your head.

Not so with C.



 
>> But basically, he started GNU emacs and designing
>> emacs lisp slightly beforem the CL standardization
>> process started, and it was far from obviouos that
>> it would succeed (it took ten years!).
>
> OK, but when it did "succeed", why not then?

It would have been too much work for a single programmer, and he
probably already had a lot of users writing emacs lisp code like crazy
demons.


> And, cannot CL be used from Elisp, with explicit
> notation (actually naming), but nonetheless?

Yes. There's emacs-cl.  But it bit-rotted on the passage from emacs 23
to 24 with lexical binding.



-- 
__Pascal Bourguignon__                 http://www.informatimago.com/
“The factory of the future will have only two employees, a man and a
dog. The man will be there to feed the dog. The dog will be there to
keep the man from touching the equipment.” -- Carl Bass CEO Autodesk


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