Re: seq-some-p and nil

[Mark Oteiza <mvoteiza@udel.edu>]

On 08/09/15 at 01:50pm, Stefan Monnier wrote:
> >   (defun seq-some (pred seq)
> >     (funcall pred (seq-find (pred seq)))
> 
> But that fails for the case where the element found is nil.

Works as expected

  (cl-defgeneric seq-find (pred seq)
    (catch 'seq--break
      (seq-doseq (elt seq)
        (when (funcall pred elt)
          (throw 'seq--break elt)))
      nil))

  (cl-defgeneric seq-some (pred seq)
    (funcall pred (seq-find pred seq)))

  (seq-find 'null [1 2 nil])
  ;; => nil

  (seq-some 'null [1 2 nil])
  ;; => t

It's not a "semantic problem" or a "corner case", if one is really
curious if their sequence has a nil value, seq-find isn't the way to
find out.