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

[Michael Heerdegen]

Michael Heerdegen <address@hidden> writes:

> 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

Yes, because with the current definition

#+begin_src emacs-lisp
(defun stream-concatenate (stream-of-streams)
  "Concatenate all streams in STREAM-OF-STREAMS and return the result.
All elements in STREAM-OF-STREAMS must be streams.  The result is
a stream."
  (seq-reduce #'stream-append stream-of-streams (stream-empty)))
#+end_src

when S=s1,s2,s3,..., then

  (stream-concatenate S)

will return s a stream that will find its elements like

  (stream-append s1 (stream-append s2 (stream-append s3 ...)...))

which can be of arbitrary depth.

Will suggest a patch soon.


Michael.