removing flatten-list (alias for new flatten-tree function)

removing flatten-list (alias for new flatten-tree function)

[Paul Eggert]

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Thanks for writing the new flatten-tree function and cleaning up 
existing duplicate functions. I tweaked its performance a bit and 
cleaned up some more duplicates. While doing that I found that I was 
confused by the existence of the just-added alias 'flatten-list', and I 
propose removing it as per the attached patch. I think people who want 
to find and use the new 'flatten-tree' function will typically be better 
served if it has just one name that fits in with existing Emacs Lisp 
functions like 'copy-tree', as opposed to also having a name that is a 
misnomer.


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From b1c894069483adf39b5f4d1f0cdd8f1aeecb87e9 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Mon, 17 Dec 2018 10:28:14 -0800
Subject: [PATCH] * lisp/subr.el (flatten-list): Remove.

---
 etc/NEWS     | 6 ++----
 lisp/subr.el | 4 ----
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/etc/NEWS b/etc/NEWS
index 327276eef9..9c6401d204 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1360,10 +1360,8 @@ are implemented in C using the Jansson library.
 'ring-resize' can be used to grow or shrink a ring.
 
 +++
-** New function 'flatten-tree'.
-'flatten-list' is provided as an alias. These functions take a tree
-and 'flatten' it such that the result is a list of all the terminal
-nodes.
+** New function 'flatten-tree' returns a "flattened" copy of a tree,
+such that the result is a list of all the terminal nodes.
 
 ** Mailcap
 
diff --git a/lisp/subr.el b/lisp/subr.el
index c5004a539b..0bb04d5e0a 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -5466,8 +5466,4 @@ flatten-tree
     (if tree (push tree elems))
     (nreverse elems)))
 
-;; Technically, `flatten-list' is a misnomer, but we provide it here
-;; for discoverability:
-(defalias 'flatten-list 'flatten-tree)
-
 ;;; subr.el ends here
-- 
2.19.2

Re: removing flatten-list (alias for new flatten-tree function)

[Alex Branham]

On Mon 17 Dec 2018 at 12:40, Paul Eggert <eggert@cs.ucla.edu> wrote:

> Thanks for writing the new flatten-tree function and cleaning up
> existing duplicate functions. I tweaked its performance a bit and
> cleaned up some more duplicates.

Thanks!

> While doing that I found that I was confused by the existence of the
> just-added alias 'flatten-list', and I propose removing it as per the
> attached patch. I think people who want to find and use the new
> 'flatten-tree' function will typically be better served if it has just
> one name that fits in with existing Emacs Lisp functions like
> 'copy-tree', as opposed to also having a name that is a misnomer.

The reason I included `flatten-list' was that the existing
implementations (both inside and outside of Emacs) were nearly all
called foo-flatten-list or similar. I thought it would perhaps be easier
for people to find `flatten-list' than `flatten-tree'. I don't have a
really strong opinion about this, though.

Alex

RE: removing flatten-list (alias for new flatten-tree function)

[Drew Adams]

> > While doing that I found that I was confused by the existence of the
> > just-added alias 'flatten-list', and I propose removing it as per the
> > attached patch. I think people who want to find and use the new
> > 'flatten-tree' function will typically be better served if it has
> > just one name that fits in with existing Emacs Lisp functions like
> > 'copy-tree', as opposed to also having a name that is a misnomer.
> 
> The reason I included `flatten-list' was that the existing
> implementations (both inside and outside of Emacs) were nearly all
> called foo-flatten-list or similar. I thought it would perhaps be
> easier for people to find `flatten-list' than `flatten-tree'. I
> don't have a really strong opinion about this, though.

Yes.  I don't know whether an alias is needed, but this
should be pointed out in the doc, because Elisp is part
of the history of Lisp.  Flattening a (Lisp) list has
pretty much always meant flattening it throughout. 

If you want to use an alias that mentions "list", consider
`deep-flatten-list'.

"Deep" usually conveys recursively performing some action
at all levels.  And it's understood by most developers,
using most languages.