Re: Making a non-ASCII space character visible

[Will Parsons]

On Sunday, 17 Jun 2018  1:55 AM -0400, Eli Zaretskii wrote:
>> From: Michael Heerdegen <michael_heerdegen@web.de>
>> Date: Sun, 17 Jun 2018 07:07:30 +0200
>> Cc: help-gnu-emacs@gnu.org
>> 
>> Will Parsons <varro@nodomain.invalid> writes:
>> 
>> > I have a desire to use the Unicode character A007 (FIGURE SPACE) in a
>> > document and to be able to distinguish it visually from a regular ASCII
>> > space.  This seems to be already done in the case of 00A0 (NO-BREAK
>> > SPACE) which appears as an underscore with a distinctive face.
>> >
>> > It *looks* like I should be able to do this via the customization
>> > option "Whitespace Display Mappings", but no matter what I do,
>> > attempting to "Apply" the changes results in an error message, "This
>> > field should contain a single character".
>> 
>> Seems you tried to insert a printed representation of the character?
>> AFAIK you must insert the character.  You can achieve this with M-:
>> (insert ?\x2007) for example.  Yes, that's not so nice.
>
> ??? How does that differ from "C-x 8 RET 2007 RET"?  The latter is the
> standard way of inserting characters in Emacs.
>
> If you did succeed to customize that variable, can you show a step by
> step recipe?

As I stated in my original post, I manually edited my custom.el file.
That seems to have succeeded, because if I display the variable
whitespace-display-mappings, I see:

Value: ((space-mark 32
             [183]
             [46])
 (space-mark 160
             [164]
             [95])
 (space-mark 8199
             [164]
             [95])
 (newline-mark 10
               [36 10])
 (tab-mark 9
           [187 9]
           [92 9]))

Original value was 
((space-mark 32
             [183]
             [46])
 (space-mark 160
             [164]
             [95])
 (newline-mark 10
               [36 10])
 (tab-mark 9
           [187 9]
           [92 9]))

-- 
Will