bug#27584: 26.0.50; alist-get: Add optional arg TESTFN

[Michael Heerdegen]

Tino Calancha <tino.calancha@gmail.com> writes:

> I rewrote it as follows:
>
>   (declare (compiler-macro
>             (lambda (form)
>               (pcase pred
>                 (''eq `(assq ,key ,alist))
>                 ((or ''equal 'nil) `(assoc ,key ,alist))
>                 ((and (guard (macroexp-const-p key)) ''eql)
>                  (if (floatp key)
>                      `(assoc ,key ,alist) `(assq ,key ,alist)))
>                 (t form)))))

Is this a good idea in general?  PRED could also be function-quoted, or
a variable bound to `eq'.  And KEY could be an expression that evaluates
to a float.  That would fail the `floatp' test.


Michael.