Re: [yazicivo@ttnet.net.tr: Locale Dependent Downcasing in smtpmail]

[Richard Stallman <rms@gnu.org>]

    > After the release, it would be good to design a new case conversion
    > system which can handle the cases where one letter converts to more
    > than one.  It would be nice if it could even handle German.
    > This could be done thru the spell checker.

    Compare the following excerpt from the Aspell manual (appendix C.4):

    The German Sharp S or Eszett does not have an uppercase equivalent.
    Instead when `ß' is converted to `SS'.  The conversion of `ß' to `SS'
    requires a special rule, and increases the length of a word, thus
    disallowing inplace case conversion.  Furthermore, my general rule of
    converting all words to lowercase before looking them up in the
    dictionary won't work because the conversion of `SS' to lowercase is
    ambiguous; it can be `ss' or `ß'.  I do plan on dealing with this
    eventually.

That is not a problem for the method I have in mind.  Emacs can
generate all the possible downcasings of a word containing SS,
then send each one to Aspell to see if it is the right one.
Aspell can handle lower-case words, so this will work.

Meanwhile, this suggests a way that Aspell could handle the upper case
German words: generate the various possible downcasings of it.  (If
there are N occurrences of SS, there will be 2**N possible
downcasings.)  Then see if any of them is in the dictionary.  If so,
the upper case word is valid.  Otherwise, construct the union of the
suggestion-lists from the various possible downcasings.

I cc'd the Aspell maintainer so that he will see this idea.