Re: Wrapping my head around icon-map-list

Michael Heerdegen via Users list for the GNU Emacs text
editor <[email protected]> writes:

> Antonio Romano <[email protected]> writes:

>> Having read this, I tried edited the `icon-map-list` as by prepending
>> a personal alist as follows:
>>
>> (setopt icon-map-list (cons '("etc/images/diropen" . "document-new")
>> 			    icon-map-list))
>>  => (("etc/images/diropen" . "document-new") x-gtk-stock-map)
>        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>      This is not an alist, it is a single element.
>
> So there is a level of parens missing, no?
>
>> but opening Emacs now results in the toolbar failing to show and the
>> frame doing some weird display glitches. Trying to append the alist
>> does
>> nothing, instead. What am I doing wrong? Is this variable even planned
>> for personal customization?
>
> It's a user option so I would definitely assume it.

As the docstring for ‘icon-map-list’ says, this user option
is "A list of alists...".  So, its updated value should be:

   ((("etc/images/diropen" . "document-new")) x-gtk-stock-map)

The first alist in this list is: 

   (("etc/images/diropen" . "document-new"))

and the second alist in this list is:

   x-gtk-stock-map

At this point, the advice that it ought to be possible to
give to an Emacs user is to customize the option using the
command ‘customize-option’:

   M-x customize-option RET icon-map-list RET

The Easy Customization interface is supposed to help Emacs
users by writing the necessary Emacs Lisp expression to set
a user option, so the user does not need to know the details
of how to write the expression, such as the type(s) of
arguments needed.

Unfortunately, though, it appears that the Easy
Customization interface sets the value of ‘icon-map-list’ to
the same value as the original value set by the poster, that
is,

   icon-map-list => (("etc/images/diropen" . "document-new") x-gtk-stock-map)

which is not a list of association lists.  This appears to
be an error in the code that sets the value of this user option.

-- 
The lyf so short, the craft so long to lerne.
- Geoffrey Chaucer, The Parliament of Birds.