Behavior of incf with characters?
Stephen J. Turnbull
stephen at xemacs.org
Tue Mar 16 13:08:51 EDT 2010
Ben Wing writes:
> Checking the type of an object to determine if it's a character is not
> expensive. Implementing "next in charset" semantics is fairly cheap
> if done in C and if we don't try to implement the "skip over holes"
> behavior. I'd tend to disfavor skipping over holes in any case --
> from XEmacs's perspective these are valid characters, just with
> undefined semantics,
I think this is taking the representation way to seriously, especially
since we all basically agree that the representation has to be
replaced with some sort of internal Unicode, where there *are*
non-characters (about a dozen in the BMP) that will never ever be
BTW, what is your use case for incf (or other arithmetic) on
characters? I don't actually see a real use case for incf returning a
character, especially one of "undefined semantics".
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