Re: face for non-ASCII characters

[Ted Zlatanov]

On Tue, 26 Apr 2011 14:26:13 -0400 Chong Yidong <address@hidden> wrote: 

CY> Richard Stallman <address@hidden> writes:
>> After that I changed it so the user can review and decide at each
>> opportunistic install.
>> 
>> This is not a binary question, it's a scale.  You want to take a step
>> towards the wrong end of the scale.  We are just introducing the
>> separate package archive, which is a big step.  Now is too soon to
>> consider another step.  The risk here is hard to calculate, so we must
>> be cautious.

CY> For what it's worth, I don't think general-case opportunistic
CY> installation is a good idea, even from a strictly technical standpoint.

CY> One can imagine special instances where one might wish to prompt the
CY> user, at a very specific point during the execution of a command, to
CY> install a package.  In fact, this can be done easily using the existing
CY> package.el infrastructure (or even without package.el; this is Lisp,
CY> after all).

OTOH it's very nice to be told "hey, you could have X if you installed
package Y."  I think it's good to know about these opportunities at
customization time.

For example, markchars.el has optional behavior if idn.el is installed.
It would be nice if the customization for `markchars-what' connected the
'markchars-nonidn-fun option with the idn.el package, so that 1) the
user knows there's a connection, and 2) the user can choose to enable
'markchars-nonidn-fun and *at that time* must install idn.el as well.

This could be done in customization code like this:

(defcustom markchars-what
  `(markchars-simple-pattern
    markchars-confusables
    ,@(when (fboundp 'idn-is-recommended) '(markchars-nonidn-fun)))
  "Things to mark, a list of regular expressions or symbols."
  :type `(repeat (choice :tag "Marking choices"
                         (const
                          :required-feature 'idn ; NEW Custom tag
                          :tag "Non IDN chars (Unicode.org tr39 suggestions)"
                          markchars-nonidn-fun)
                         (const :tag "Confusables" markchars-confusables)
                         (const :tag "`markchars-simple-pattern'"
                                markchars-simple-pattern)
                         (regexp :tag "Arbitrary pattern")))
  :group 'markchars)

Note the awkwardness of the default, which could also be remedied by
this new tag.

Ted