Re: Non-ASCII chars in quail rules

[Stefan Monnier <monnier@IRO.UMontreal.CA>]

> One note: CHARACTERP does a bit more than is actually needed here, it
> may be sufficient to say XINT (c) <= MAX_CHAR or to use the
> CHAR_VALID_P macro.

The only "more" it does, compared to XINT (c) <= MAX_CHAR is that it
checks >=0 which is redundant because we already compared with ' '.

> I am not sure what the intent here of the restriction was, but a more
> general solution for the entire line of the test might be
> CHAR_PRINTABLE_P depending on what that intent actually is. (I don't
> entirely understand the intent, so I can't say.)

The intent is to make sure that `c' is something we can insert in the
buffer (since that's what quail does).  We could also remove this check
completely and allow using any event to trigger input-method-function,
but that does break the current quail.el, so it's clearly more "backward
incompatible".


        Stefan