Re: elisp - anonymous function in an association list?

[Barry Margolin]

In article <85k5o13w4q.fsf@lola.goethe.zz>, David Kastrup <dak@gnu.org> 
wrote:

> apatheticagnostic <apatheticagnostic@gmail.com> writes:
> 
> > On Nov 29, 9:50 am, Marc Tfardy <m-t-o___CUT__IT...@web.de> wrote:
> >> apatheticagnostic schrieb:
> >>
> >> > take, for example this code showing what I mean:
> >>
> >> > (defvar sample-alist '(("a" '(lambda ()
> >> >                                 (message "We worked!")))
> >> >                        ("b" #'(lambda ()
> >> >                                 (message "B worked too!")))))
> >>
> >> > (defun test-call (x)
> >> >   (funcall (cdr (assoc x sample-alist))))
> >>
> >> > (test-call "a")
> >> > (test-call "b")
> >>
> >> > Both calls fail, with an error message like so:
> >>
> >> This seems to work:
> >>
> >> (defvar sample-alist '(("a" (lambda () (message "We worked!")))
> >>                         ("b" (lambda () (message "B worked too!")))))
> 
> [fixed to omit the utterly pointless eval:]
> 
> >> (defun test-call (x)
> >>    (funcall (car (cdr (assoc x sample-alist)))))
> 
> > So it does. Well, I feel dumb now. I assumed that I would need to
> > quote the lambda expressions in some way to prevent them from being
> > evaluated at definition.
> 
> lambda is self-quoting.  It is preferable not to quote it nevertheless,
> because then the byte compiler can compile and optimize it.

The self-quoting of lambda is not the issue here.  He already quoted the 
list -- the problem was that he embedded another quote within the list.  
This simply quoted the quote.
-- 
Barry Margolin
Arlington, MA