Re: [office-formula] combining characters

[Robert Weir/Cambridge/IBM <robert_weir@us.ibm.com>]

There is a Unicode FAQ on this question:

http://unicode.org/faq/char_combmark.html#7

It lists three ways of looking at string length, and it looks like 
Gnumeric and Calc are doing method #2.

Whatever we do, I think we need to ensure consistency across the range of 
string manipulation functions, since they are typically used in 
conjunction with each other. 

So in your example, would FIND("eì","e") return 1?  Would LEFT("eì",1) 
return 'e'?  And what would RIGHT("eì",1) return?  and UPPER("eì")?  And 
LEN(UPPER("eì"))?

I think it is far more challenging to define these functions in an 
intuitive and self-consistent fashion if we assume that the strings are 
normalized. 

However, if the apps themselves are not behaving in an intuitive and 
self-consistent fashion, then that is another challenge.

I can certainly forgive LEFTB and such, since they are hitting the lower 
level character representations.  But I think that the basic LEN,RIGHT, 
LEFT, etc., functions we want to be working with user expectations on how 
text works.  Not being a user of compose sequences, I am on uncertain 
ground here.  Does anyone have a good sense of this?  For example, when a 
user enters a compose sequence, do they think of it as a short cut for 
entering a single character?  Or do they think of it as a way of entering 
multiple characters that may display as a single glyph, but behave like 
multiple characters when doing string operations?

-Rob

Andreas J Guelzow <aguelzow@math.concordia.ab.ca> wrote on 09/01/2009 
11:19:23 AM:
> 
> Just for the record, in both OOo3.1 and Gnumeric 1.9.10 we have
> =len("eì")
> evaluating as 2 if the accented e is entered using combining characters.
> 
> Andreas
> -- 
> Andreas J. Guelzow
> Concordia University College of Alberta
>