setup_ccl_program in ccl_init_coding_stream

[Aidan Kehoe]

 Ar an dara lá is fiche de mí Meitheamh, scríobh Stephen J. Turnbull: 

 > If you look at the commentary on the related functions, you can see that
 > I was heading in the direction of getting them out of the coding-system
 > business as much as possible. Instead, I'd just unify (or de-unificate,
 > in the case of Han sets) *charsets*, and let some other facility handle
 > choosing an appropriate coding system. Ie, not caring whether non-Latin
 > charsets were present or not was more or less by design.

Well, “less,” because that wasn’t what you said in the docstrings :-) . Your
commentary is also full of things like: 

;; #### I see nothing useful to be done with APPEND.
;; FILENAME, VISIT, or LOCKNAME could be used to default the coding system,
;; but this would conflict with the semantics of `write-region'.
;; #### The efficiency of this function can clearly be improved.
;; #### This function should be set up to call the check functions in a
;; condition-case, and call out to error handlers.  Then tests could be
;; written more easily.

which is only readable in the event that you’re modifying the package and
have looked at the details of the implementation, rather than just the
interfaces. I didn’t read the commentary in detail as a result, since I was
interested in using the package. 

 > Unfortunately, I don't recall how far that program proceeded (I didn't
 > The technical problem is that non-Latin charsets were inconceivable to
 > latin-unity.  The following patch adds a signal that tells latin-unity
 > "whoa, hands off!"  Unfortunately, this means that you can't remap a
 > region that contains non-Latin characters *at all*; you need to
 > restrict attention to Latin-only regions.

That’s fine, I think; previously, remapping a region with non-Latin
characters would do something other than the docstring would lead you to
expect. And one can restrict attention to Latin-only regions with a
combination of skip-chars-forward, char tables, and the
latin-unity-character-sets variable.

 > The recoding functions may need similar treatment, I haven't looked yet.
 > 
 > I'm almost sure this will cause annoyance to somebody, but most such
 > somebodies *probably* can just turn off latin-unity.

Hmm, I actually doubt it, but we’ll see. 

-- 
Santa Maradona, priez pour moi!