Paul Rohr <[EMAIL PROTECTED]> wrote in
news:[EMAIL PROTECTED]: 

>  How should undo work for combining characters?

Well, combining characters may be input in several ways. On my 
Norwegian keyboard, I write � by pressing the Alt Gr + 'the � 
deadkey', followed by an e. (BTW, note that the decomposed form of 
� in Unicode is e�, not �e.) On French keyboards, I believe there 
is a separate � key. But exactly how the keypress --> character 
sequence is generated should be done by the OS.

As for undoing a decomposed character (e.g. e�), I think it's safe 
to undo all characters back to (and including) the last non-
combining character. For example if you write e� (where � is not 
actually �, but the combining �) and press undo, both characters 
(which are probably displayed as one glyph) should be deleted. (In 
practice � would/should be written as the pre-composed � character, 
as per Normalization Form�C <URL: 
http://www.unicode.org/unicode/reports/tr15/ >. I only use it here 
as an exaple.)

> What would a native speaker want to happen when you "undo" the
> entry of a single "on-screen" character?[1]  I suspect that
> creating such an entity may take more than one step (in the
> input method editor), but should they always be undone
> individually?

In case similar to my example above, yes. But not always. See for 
example the romaji input example at <URL: 
http://www.w3.org/TR/charmod/#sec-CharExamples >. How this should 
be handled is depedant on the actual input method used.

-- 
Karl Ove Hufthammer

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