Re: [PATCH] Gnu Elpa: stream.el: Add some more basic stream operations

[Michael Heerdegen]

Nicolas Petton <address@hidden> writes:

> > I updated the patch.

Hmm, seems my implementation of `stream-concatenate' is too recursive
"when executed":

#+begin_src emacs-lisp
(seq-into-sequence
 (stream-concatenate
  (seq-map
   (lambda (n) (stream (list n)))
   (stream (number-sequence 1 500)))))

stream-empty-p: Lisp nesting exceeds `max-lisp-eval-depth'
#+end_src

The standard approach seems to work in this case OTOH, e.g. with (don't
forget to eval the example with lexical-binding turned on!):

#+begin_src emacs-lisp
(defun stream-concatenate (stream-of-streams)
  (while (and (not (stream-empty-p stream-of-streams))
              (stream-empty-p (stream-first stream-of-streams)))
    (cl-callf stream-rest stream-of-streams))
  (if (stream-empty-p stream-of-streams)
      (stream-empty)
    (stream-cons
     (stream-first (stream-first stream-of-streams))
     (stream-concatenate
      (stream-cons (stream-rest (stream-first stream-of-streams))
                   (stream-rest stream-of-streams))))))
(progn
  (seq-into-sequence
   (stream-concatenate
    (seq-map
     (lambda (n) (stream (list n)))
     (stream (number-sequence 1 50000)))))
  nil ;Don't display the result, please
  )
==> nil
#+end_src

So I guess we should replace the current implementation.


Michael.