Re: (. wtf?)

[<tomas@tuxteam.de>]

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On Sun, May 07, 2023 at 09:06:21PM +0300, Dmitry Alexandrov wrote:
> On Fri, 05 May 2023 16:35 Ludovic Courtès <civodul@toot.aquilenet.fr> wrote:
> > (call-with-input-string "(. wtf?)" read)
> >
> > ⇒ wtf?
> >
> > #Guile #Scheme
> 
> Hey!^W  Sorry...
> 
> Dear Guile developer,
> 
> your tweet made me deeply concerned.  Is it a sign that this behaviour is going to be ‘fixed’ eventually?
> 
> Besides actually being (imho) the only right thing to do: explanation below aside, just compare:
> #+begin_src scheme
> (define (fu bar) ...)
> (λ (bar) ...)
> (define (fu . quux) ...)
> (λ (. quux) ...)
> #+end_src
> 
> it is required for compatibility with elisp; where itʼs not only observed de-facto:
> #+begin_src elisp
> '(. foo)
> ;; ⇒ foo
> #+end_src
> 
> but explicitly documented in (info "(elisp) Dotted Pair Notation") as well:
> #+begin_quote
>    As a somewhat peculiar side effect of ‘(a b . c)’ and ‘(a . (b . c))’
> being equivalent, for consistency this means that if you replace ‘b’
> here with the empty sequence, then it follows that ‘(a . c)’ and ‘(a . (
> . c))’ are equivalent, too.  This also means that ‘( . c)’ is equivalent
> to ‘c’, but this is seldom used.
> #+end_quote

You seem to be somewhat upset, but I don't quite understand what
your gripe is. Is it the (define (...) ...) shorthand function
definition in Guile? Is it Guile's incompatibility with Emacs
Lisp (no wonder: the first is a Scheme, the second a Lisp: they
are related, but pretty different)?

Could you explain a bit better?

Cheers
-- 
t

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