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Re: [PATCH] Gnu Elpa: stream.el: Add some more basic stream operations
From: |
Michael Heerdegen |
Subject: |
Re: [PATCH] Gnu Elpa: stream.el: Add some more basic stream operations |
Date: |
Sat, 17 Sep 2016 01:52:25 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) |
Yuri Khan <address@hidden> writes:
> > Would it make sense to add an `seq-take-until' for convenience?
>
> seq-take-until might be a fitting addition to seq-take-while.
> seq-drop-until, for completeness?
Hmm, isn't `seq-drop-until' redundant - because it's the same as
`seq-drop-while' with negated predicate?
For example, if stream
S = 0, 0, ..., 0, 1, 2, 3, ...
then naturally would
(seq-drop-while #'zerop S) == 1, 2, ...
== (seq-drop-until
(lambda (n) (not (zerop n)))
S)
`seq-take-until' is obviously not redundant in the same way. So, why is
the symmetry broken? I think the problem is the wording:
`seq-drop-until' is simply not the natural counterpart of
`seq-drop-while'.
We would want a function seq-X so that
(seq-X #'zerop S) == 0, 1, 2, ...
I think that this function would be useful (I already needed it). But
what word sequence X would describe these semantics (how should we call
the function)?
Michael.
- Re: [PATCH] Gnu Elpa: stream.el: Add some more basic stream operations,
Michael Heerdegen <=
- Re: [PATCH] Gnu Elpa: stream.el: Add some more basic stream operations, Yuri Khan, 2016/09/17
- Re: [PATCH] Gnu Elpa: stream.el: Add some more basic stream operations, Michael Heerdegen, 2016/09/25
- Re: [PATCH] Gnu Elpa: stream.el: Add some more basic stream operations, Yuri Khan, 2016/09/25
- Re: [PATCH] Gnu Elpa: stream.el: Add some more basic stream operations, Michael Heerdegen, 2016/09/27
- Re: [PATCH] Gnu Elpa: stream.el: Add some more basic stream operations, Yuri Khan, 2016/09/28
- Re: [PATCH] Gnu Elpa: stream.el: Add some more basic stream operations, Nicolas Petton, 2016/09/28
- Re: [PATCH] Gnu Elpa: stream.el: Add some more basic stream operations, Michael Heerdegen, 2016/09/28
- Re: [PATCH] Gnu Elpa: stream.el: Add some more basic stream operations, Yuri Khan, 2016/09/28
- Re: [PATCH] Gnu Elpa: stream.el: Add some more basic stream operations, John Wiegley, 2016/09/25