# \[Pitch\] Unicode for String Processing

**URL:** <https://forums.swift.org/t/pitch-unicode-for-string-processing/56907>\
**Category:** Pitches\
**Created:** [April 22, 2022, 7:30pm UTC](https://forums.swift.org/t/pitch-unicode-for-string-processing/56907 "2022-04-22T19:30:04Z")\
**Posts on this page:** 1\
**Showing post:** 6

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**Author:** ![YOCKOW](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/yockow/32/20636_2.png) [@YOCKOW](https://forums.swift.org/u/YOCKOW)\
**Post date:** [April 28, 2022, 4:36am UTC](https://forums.swift.org/t/pitch-unicode-for-string-processing/56907/6 "2022-04-28T04:36:55Z")

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> [@nnnnnnnn](#):
>
> Swift's `Regex` follows the level 2 guidelines for Unicode support in regular expressions described in [Unicode Technical Standard #18](https://unicode.org/reports/tr18/),

"2.4 [Default Case Conversion](https://unicode.org/reports/tr18/#Default_Loose_Matches)" is described as retracted, and it implies there could be various implementations:

> Some implementations may choose to have a mixed solution, where they do full case matching on literals such as "Strauß", but simple case folding on character classes such as [ß].

I wonder how `ignoresCase(_:)` in this pitch is expected to work.  
Would it be locale-independent?  
Would it take some options, for example, to choose full case folding or simple case folding?

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