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Re: combining cond and let, to replace pcase.


From: Richard Stallman
Subject: Re: combining cond and let, to replace pcase.
Date: Sat, 25 Nov 2023 22:14:20 -0500

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  > >        ;; Same as a clause in `cond',
  > >        (CONDITION
  > >         do-this-if-CONDITION-then-exit...)
  > >
  > >        ;; Variables to bind, as in let
  > >        (:bind (x foobar) y z (foo 5) a)
  > >        ;; Bindings continue in effect.

  > This seems nicer:

  > (if CONDITION
  >     do-this-if-CONDITION-then-exit...
  >     (let ((x foobar) y z (foo 5) a)
  >       ...))

That is what you can do now with `if' and `let', but many levels of
nexting get to be inconvenient and hard to read.  That is one of the
practical conveniences of _using_ `pcase'.  I think a replacement for
`pcase' should offer the same advantage.

  > It looks like everybody is trying to design a "do it all super-macro"

If that refers to the approach of `pcase', in which there are dozens
of different features one must learn, then `cond*' represents turning
away from that approach.  `cond*' has just four features, two of which
are modified from `cond'.

That's why `cond*' will impose less burden of language complexity than
`pcase'.

-- 
Dr Richard Stallman (https://stallman.org)
Chief GNUisance of the GNU Project (https://gnu.org)
Founder, Free Software Foundation (https://fsf.org)
Internet Hall-of-Famer (https://internethalloffame.org)





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