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Re: Stream implementation of seq-mapn
From: |
Michael Heerdegen |
Subject: |
Re: Stream implementation of seq-mapn |
Date: |
Tue, 26 Dec 2017 23:09:04 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) |
Hello,
I uploaded a slightly tweaked version and added regression tests (but
didn't bump the package version). I also reported the method signature
problem as "bug#29786: 27.0.50; About the argument list of methods".
Unanswered until now, so the generated help for the method still looks
weird.
For completeness, here is what I committed:
>From 93e9009c827bc5b0f67c683a4e1748c90c6e4686 Mon Sep 17 00:00:00 2001
From: Michael Heerdegen <address@hidden>
Date: Mon, 18 Dec 2017 12:49:38 +0100
Subject: [PATCH] Implement `seq-mapn' method for streams
* stream/stream.el (seq-mapn): New method.
* stream/tests/stream-tests.el (stream-seq-mapn-test): New test.
And add a `deftest-for-delayed-evaluation'.
---
packages/stream/stream.el | 22 ++++++++++++++++++++++
packages/stream/tests/stream-tests.el | 15 +++++++++++++++
2 files changed, 37 insertions(+)
diff --git a/packages/stream/stream.el b/packages/stream/stream.el
index b412807e2..3f6bc4b5b 100644
--- a/packages/stream/stream.el
+++ b/packages/stream/stream.el
@@ -321,6 +321,28 @@ applications of FUNCTION on each element of STREAM in
succession."
(cons (funcall function (stream-first stream))
(seq-map function (stream-rest stream))))))
+(cl-defmethod seq-mapn (function (stream stream) &rest streams)
+ "Map FUNCTION over the STREAMS.
+
+Example: this prints the first ten Fibonacci numbers:
+
+ (letrec ((fibs (stream-cons
+ 1
+ (stream-cons
+ 1
+ (seq-mapn #'+ fibs (stream-rest fibs))))))
+ (seq-do #'print (seq-take fibs 10)))
+
+\(fn FUNCTION STREAMS...)"
+ (if (not (seq-every-p #'streamp streams))
+ (cl-call-next-method)
+ (cl-labels ((do-mapn (f streams)
+ (stream-make
+ (unless (seq-some #'stream-empty-p streams)
+ (cons (apply f (mapcar #'stream-first streams))
+ (do-mapn f (mapcar #'stream-rest
streams)))))))
+ (do-mapn function (cons stream streams)))))
+
(cl-defmethod seq-do (function (stream stream))
"Evaluate FUNCTION for each element of STREAM eagerly, and return nil.
diff --git a/packages/stream/tests/stream-tests.el
b/packages/stream/tests/stream-tests.el
index decf3ad47..896c72993 100644
--- a/packages/stream/tests/stream-tests.el
+++ b/packages/stream/tests/stream-tests.el
@@ -166,6 +166,18 @@
(should (= -1 (stream-first (seq-map #'- (stream-range 1)))))
(should (= -2 (stream-first (stream-rest (seq-map #'- (stream-range 1)))))))
+(ert-deftest stream-seq-mapn-test ()
+ (should (streamp (seq-mapn #'+ (stream (list 1 2 3)) (stream (list 4 5 6)))))
+ (should (not (streamp (seq-mapn #'+ (stream (list 1 2 3)) (stream (list 4 5
6)) (list 7 8 9)))))
+ (should (= 2 (seq-length (seq-mapn #'+ (stream (list 1 2 3)) (stream (list 4
5))))))
+ (should (equal (letrec ((fibs (stream-cons
+ 1
+ (stream-cons
+ 1
+ (seq-mapn #'+ fibs (stream-rest fibs))))))
+ (seq-into (seq-take fibs 10) 'list))
+ '(1 1 2 3 5 8 13 21 34 55))))
+
(ert-deftest stream-seq-do-test ()
(let ((result '()))
(seq-do
@@ -292,6 +304,9 @@
(deftest-for-delayed-evaluation (seq-drop (make-delayed-test-stream) 2))
(deftest-for-delayed-evaluation (seq-take-while #'numberp
(make-delayed-test-stream)))
(deftest-for-delayed-evaluation (seq-map #'identity
(make-delayed-test-stream)))
+(deftest-for-delayed-evaluation (seq-mapn #'cons
+ (make-delayed-test-stream)
+ (make-delayed-test-stream)))
(deftest-for-delayed-evaluation (seq-filter #'cl-evenp
(make-delayed-test-stream)))
(deftest-for-delayed-evaluation (stream-delay (make-delayed-test-stream)))
(deftest-for-delayed-evaluation (seq-copy (make-delayed-test-stream)))
--
2.15.1
Thanks,
Michael.
- Stream implementation of seq-mapn, Michael Heerdegen, 2017/12/18
- Re: Stream implementation of seq-mapn, Nicolas Petton, 2017/12/18
- Re: Stream implementation of seq-mapn, Michael Heerdegen, 2017/12/18
- Re: Stream implementation of seq-mapn, Nicolas Petton, 2017/12/18
- Re: Stream implementation of seq-mapn, Michael Heerdegen, 2017/12/19
- Re: Stream implementation of seq-mapn, Nicolas Petton, 2017/12/19
- Re: Stream implementation of seq-mapn,
Michael Heerdegen <=
- Re: Stream implementation of seq-mapn, Nicolas Petton, 2017/12/29
- Re: Stream implementation of seq-mapn, Michael Heerdegen, 2017/12/30