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Subject: |
25.0.93; cl.texi (for var on list by func): Fix documentation |
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Date: |
Tue, 17 May 2016 00:49:02 +0900 (JST) |
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User-agent: |
Alpine 2.20 (LRH 67 2015-01-07) |
* doc/misc/cl.texi (for var on list by func): Fix documentation
'cl-loop for var on list by func' behaves as in CL: 'on' expression
need to be a list.
The following tests run in the *scratch* buffer return
same values as in SBCL:
;; CL cl-loop -> loop
emacs -Q:
(require 'cl-lib)
(setq preys '("grass" "lion" "rabbit"))
(defun next-prey (x)
"Return the name of the prey of animal X."
(cl-loop while (not (atom x))
do (setq x (car x)))
(cond ((member x preys) ; elisp
;; (cond ((member x preys :test #'string=) ; CL
(cond ((string= x "lion") "rabbit")
((string= x "rabbit") "grass")
(t nil)))
(t
nil)))
(defun next-prey-list (x)
"Return a list with the name of the prey of animal X."
(let ((res (next-prey x)))
(if res
(list res)
nil)))
[A] (mapcar 'next-prey '("grass" "lion" "rabbit"))
[B] (mapcar 'next-prey-list '("grass" "lion" "rabbit"))
[A] (nil "rabbit" "grass")
[B] (nil ("rabbit") ("grass"))
[I] (cl-loop for y on preys collect y)
[II] (cl-loop for y on preys by #'next-prey collect y)
[III] (cl-loop for y on (car preys) by #'next-prey collect y)
[IV] (cl-loop for y on (car preys) by #'next-prey-list collect y)
[V] (cl-loop for y on preys by #'next-prey-list collect y)
[I] (("grass" "lion" "rabbit") ("lion" "rabbit") ("rabbit"))
[II] (("grass" "lion" "rabbit"))
[III] nil
[IV] nil
[V] (("grass" "lion" "rabbit"))
In GNU Emacs 25.0.93.3 (x86_64-pc-linux-gnu, GTK+ Version 2.24.30)
Repository revision: 6de0715f5467d4b925e2dfe082174529ace3b174
From 3e1756fb4d76e34b74b96782d4509582e9ce0cd3 Mon Sep 17 00:00:00 2001
From: Tino Calancha <address@hidden>
Date: Tue, 17 May 2016 00:04:56 +0900
Subject: [PATCH] ; * cl.texi (clause 'for' with 'on'): Fix documentation
---
doc/misc/cl.texi | 12 ------------
1 file changed, 12 deletions(-)
diff --git a/doc/misc/cl.texi b/doc/misc/cl.texi
index 4137a95..319592c 100644
--- a/doc/misc/cl.texi
+++ b/doc/misc/cl.texi
@@ -1956,18 +1956,6 @@ For Clauses
@result{} ((1 2 3 4) (2 3 4) (3 4) (4))
@end example
-With @code{by}, there is no real reason that the @code{on} expression
-must be a list. For example:
-
address@hidden
-(cl-loop for x on first-animal by 'next-animal collect x)
address@hidden example
-
address@hidden
-where @code{(next-animal x)} takes an ``animal'' @var{x} and returns
-the next in the (assumed) sequence of animals, or @code{nil} if
address@hidden was the last animal in the sequence.
-
@item for @var{var} in-ref @var{list} by @var{function}
This is like a regular @code{in} clause, but @var{var} becomes
a @code{setf}-able ``reference'' onto the elements of the list
--
2.8.1
--- End Message ---
--- Begin Message ---
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Subject: |
Re: bug#23550: 25.0.93; cl.texi (for var on list by func): Fix documentation |
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Date: |
Fri, 31 Mar 2017 17:20:31 +0900 |
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User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.0.50 (gnu/linux) |
address@hidden writes:
> Tino Calancha <address@hidden> writes:
>
>> It might be useful rewrite that part to make it more clear, but i don't
>> have a clear proposal.
>
> Actually, looking at this some more, I think you should just apply your
> patch that removes this stuff completely. It's much clearer to write
> that sort of example as
>
> (cl-loop for y = "lion" then (next-prey y)
> while y collect y)
>
> And looking down the page, `for VAR = EXPR1 then EXPR2' is already
> explained well enough (as well as the equivalence to the `for VAR on
> LIST by FUNCTION' form).
Thank you.
Pushed fix into emacs-25 branch with commit:
3f0d047d2eb1fb59be2ff962c01392d8c808a654
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