Today's programming challenge - How's your Range-Fu ?

[Panke via Digitalmars-d]

On Saturday, 18 April 2015 at 08:18:46 UTC, Walter Bright wrote:
> On 4/18/2015 12:58 AM, John Colvin wrote:
>> On Friday, 17 April 2015 at 18:41:59 UTC, Walter Bright wrote:
>>> On 4/17/2015 9:59 AM, H. S. Teoh via Digitalmars-d wrote:
>>>> So either you have to throw out all pretenses of 
>>>> Unicode-correctness and
>>>> just stick with ASCII-style per-character line-wrapping, or 
>>>> you have to
>>>> live with byGrapheme with all the complexity that it 
>>>> entails. The former
>>>> is quite easy to write -- I could throw it together in a 
>>>> couple o' hours
>>>> max, but the latter is a pretty big project (cf. Unicode 
>>>> line-breaking
>>>> algorithm, which is one of the TR's).
>>>
>>> It'd be good enough to duplicate the existing behavior, which 
>>> is to treat
>>> decoded unicode characters as one column.
>>
>> Code points aren't equivalent to characters. They're not the 
>> same thing in most
>> European languages,
>
> I know a bit of German, for what characters is that not true?

Umlauts, if combined characters are used. Also words that still 
have their accents left after import from foreign languages. E.g. 
Café

Getting all unicode correct seems a daunting task with a severe 
performance impact, esp. if we need to assume that a string might 
have any normalization form or none at all.

See also: http://unicode.org/reports/tr15/#Norm_Forms