std.string does not take title case into account

[dlangBugzillaToGithub]

monarchdodra reported this on 2013-05-29T09:53:36Z

Transfered from https://issues.dlang.org/show_bug.cgi?id=10204

CC List

• bugzilla (@WalterBright)

Description

Unicode 6.2.0 introduces the notion of "Title case", making the trio of:

"Lower case" => "Title case" => "Upper case"

Example:
01c6  01c5  01c4
dž     Dž     DŽ

This means that functions such as "capitalize" are wrong because they make the assumption that "Capitalize" == "Uppercase"

Also, the tests such as:

if(std.uni.isLower(c))
    c = std.uni.toUpper(c);

are wrong, as non lower case characters may have upper case representations...

[dlangBugzillaToGithub]

monarchdodra commented on 2013-05-29T12:19:47Z

Partially fixed here:
https://github.com/D-Programming-Language/phobos/pull/1322

Fixes only to[Upper|Lower](InPlace).

however, "capitalize" is still broken.

[dlangBugzillaToGithub]

bugzilla (@WalterBright) commented on 2019-12-20T14:20:34Z

I don't completely understand the problem. Could you provide an example which produces a wrong output together with a note, what it should produce?