gnus-registry: alist-to-hashtable, hashtable-to-alist (was: message registry for Gnus)

[Reiner Steib <reinersteib+gmane@imap.cc>]

[ Digging up a very old message.  Therefore Cc-ing involved people.... ]

On Mon, Feb 24 2003, Andreas Fuchs wrote:

> Today, Ted Zlatanov <tzz@lifelogs.com> wrote:
>> Could something like hashtable-to-alist-string and
>> hashtable-from-alist-string be added to the Gnus core?  It would make
>> my life easier, and I'm definitely not the person to write reliable
>> versions of these functions :)  
>
> Me neither, but will these help:
^^^^^^^^^^^^ ???

Who actually wrote these functions?  ChangeLog.2 says:

,----[ ChangeLog.2 ]
| 2003-03-28  Teodor Zlatanov  <tzz@lifelogs.com>
| 
| 	[...]
| 
| 	* gnus-registry.el (gnus-registry-translate-to-alist)
| 	(gnus-registry-translate-from-alist, alist-to-hashtable)
| 	(hashtable-to-alist): new functions
| 	(gnus-register-spool-action): add a spool item to the registry
`----

If Andreas wrote them, it should have been documented it in the
ChangeLog as follows:

,----
| 2003-03-28  Andreas Fuchs  <asf@void.at>
| 
| 	* gnus-registry.el (alist-to-hashtable, hashtable-to-alist): New
| 	functions.
`----

(Andreas has papers on file, so no need to think about "tiny change").
If Andreas didn't write them, we need to know where they came from.

We really must be more careful about these issues!

Later these were moved to gnus-util.el and Romain added the following
comment:

,----[ gnus-util.el ]
| ;; The following two functions are used in gnus-registry.
| ;; They were contributed by Andreas Fuchs <asf@void.at>.
`----

,----[ ChangeLog ]
| 2006-04-13  Romain Francoise  <romain@orebokech.com>
| 
| 	* gnus-util.el (gnus-alist-to-hashtable, gnus-hashtable-to-alist):
| 	Moved here (and renamed) from gnus-registry.el.
| 
| 	* gnus-registry.el: Require gnus-util.
| 	Use `gnus-alist-to-hashtable' and `gnus-hashtable-to-alist'.
`----

[ I'd like to put this change in v5-10 as well, because Gnus functions
  should use the "gnus-" prefix. ]

> (defun alist-to-hashtable (alist)
>   "Build a hashtable from the values in ALIST."
>   (let ((ht (make-hash-table)))
>     (mapc
>      (lambda (kv-pair)
>        (puthash (car kv-pair) (cdr kv-pair) ht))
>      alist)
>      ht))
>
> (defun hashtable-to-alist (hash)
>   "Build an alist from the values in HASH."
>   (let ((list nil))
>     (maphash
>      (lambda (key value)
>        (setq list (cons (cons key value) list))))))

[ The current code in gnus-utils.el looks slightly different (see
  rev. 6.7): ]

--8<---------------cut here---------------start------------->8---
@@ -1,16 +1,21 @@
-(defun alist-to-hashtable (alist)
+;; The following two functions are used in gnus-registry.
+;; They were contributed by Andreas Fuchs <asf@void.at>.
+(defun gnus-alist-to-hashtable (alist)
   "Build a hashtable from the values in ALIST."
-  (let ((ht (make-hash-table)))
+  (let ((ht (make-hash-table
+            :size 4096
+            :test 'equal)))
     (mapc
      (lambda (kv-pair)
        (puthash (car kv-pair) (cdr kv-pair) ht))
      alist)
      ht))
 
-(defun hashtable-to-alist (hash)
+(defun gnus-hashtable-to-alist (hash)
   "Build an alist from the values in HASH."
   (let ((list nil))
     (maphash
      (lambda (key value)
-       (setq list (cons (cons key value) list))))))
-
+       (setq list (cons (cons key value) list)))
+     hash)
+    list))
--8<---------------cut here---------------end--------------->8---

Bye, Reiner.
-- 
       ,,,
      (o o)
---ooO-(_)-Ooo---  |  PGP key available  |  http://rsteib.home.pages.de/