Re: Faking local dynamic function bindings

[Stefan Monnier]

> This resembles an earlier version of my code, but AFAIU it has the
> disadvantage that the local macro binding is created and destroyed every
> time the anonymous function is executed, which I guess creates extra
> overhead and makes the function slower.

If that turns out to be a problem, you can do it as follows:

   (defun foo (sexpr)
     (let ((macroenv `((contains
                        . ,(lambda (regexp)
                             `(string-match ,regexp ,string))))))
       (sort
        (delq nil
              (mapcar
               (lambda (item)
                 (let ((string (assq item strings-alist)))
                   (when (eval (macroexpand-all sexpr macroenv))
                     string))
               items-alist)))
        #'string<)))


-- Stefan