update stream.el to the latest version

[gnu-emacs-elpa] / packages / stream / stream.el

diff --git a/packages/stream/stream.el b/packages/stream/stream.el
index edfb3c54be3f7a1b1dd48d1e33431f70fd1aab8a..567a9e354e8fc147a89941b1f2b34fff93481d62 100644 (file)
--- a/packages/stream/stream.el
+++ b/packages/stream/stream.el
@@ -113,6 +113,17 @@ The sequence starts at POS if non-nil, 1 otherwise."
            (char-after (point)))))
      (stream buffer (1+ pos)))))
 
+(declare-function iter-next "generator")
+
+(defun stream-from-iterator (iterator)
+  "Return a stream generating new elements through ITERATOR.
+ITERATOR is an iterator object in terms of the \"generator\"
+package."
+  (stream-make
+   (condition-case nil
+       (cons (iter-next iterator) (stream-from-iterator iterator))
+     (iter-end-of-sequence nil))))
+
 (defun stream-regexp (buffer regexp)
   (stream-make
    (let (match)
@@ -157,6 +168,22 @@ range is infinite."
   (or (cdr (thunk-force (cadr stream)))
       (stream-empty)))
 
+(defun stream-append (&rest streams)
+  "Concatenate the STREAMS.
+Requesting elements from the resulting stream will request the
+elements in the STREAMS in order."
+  (if (null streams)
+      (stream-empty)
+    (stream-make
+     (let ((first (pop streams)))
+       (while (and (stream-empty-p first) streams)
+         (setq first (pop streams)))
+       (if (stream-empty-p first)
+           nil
+         (cons (stream-first first)
+               (if streams (apply #'stream-append (stream-rest first) streams)
+                 (stream-rest first))))))))
+
 (defmacro stream-pop (stream)
   "Return the first element of STREAM and set the value of STREAM to its rest."
   (unless (symbolp stream)