Unicode Sets in 'Unicode Regular Expressions'

[Whistler, Ken]

http://userguide.icu-project.org/strings/unicodeset

Whenever UTS #18 talks of "Unicode sets", it means whatever is actually
defined in the class UnicodeSet in ICU.

--Ken

> UTS#18 'Unicode Regular Expressions' Version 17 Requirement RL1.3
> 'Subtraction and Intersection' talks of Unicode sets.  What is the
> relevant definition of a 'Unicode set'? Is it a finite set of non-empty
> strings?  Other possibilities that occur to me, depending on context,
> include sets of codepoints and sets of indecomposable codepoints.
> 
> Richard.