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Re: How the backquote and the comma really work?


From: Thorsten Jolitz
Subject: Re: How the backquote and the comma really work?
Date: Tue, 11 Aug 2015 19:20:12 +0200
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux)

Marcin Borkowski <address@hidden> writes:

Hi,

,----
| How the backquote and the comma really work?
`----

funny enough, this was discussed recently on the PicoLisp mailing list
too, and I was surprised to find out that in Emacs Lisp 'Read Macros'
like backquote/comma rather seem to work at run time, while the PicoLisp
equivalents quote/backquote work at read time.


> PicoLisp:
>
> ,----
> | $ pil +
> | : (let X (+ 2 3) '(3 4 `X))
> | -> (3 4 NIL)
> | : '(3 4 `(+ 2 3))
> | -> (3 4 5)
> `----
>
> vs Emacs Lisp:
>
> ,----
> | (let ((X (+ 2 3))) `(3 4 ,X))
> | -> (3 4 5)
> | 
> | `(3 4 ,(+ 2 3))
> | -> (3 4 5)
> `----

How does this work in Emacs Lisp? Is the backquote/comma actually a
function call at runtime?

[I did not follow the whole discussion, I hope I don't ask something
already answered]

-- 
cheers,
Thorsten




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