On December 21, 2019 10:57:02 AM GMT+01:00, Florian Schmaus <f...@geekplace.eu> wrote: >On 18.12.19 16:00, Marvin W wrote: >> It's indeed a good question if anything in XMPP allows servers or >> in-between entities to do normalization. I was under the assumption >that >> servers do not change the codepoints. In XML [1] Characters with >> multiple possible representations in ISO/IEC 10646 (e.g. characters >with >> both precomposed and base+diacritic forms) match only if they have >the >> same representation in both strings. Thus by XML specification, >> normalization is changing the body. > >I am not sure if it is not a little bit far fetched to deduce from the >XML "string match" definition that XMPP entities are not provided with >a >little bit of freedom to transform Unicode string representation within >a certain degree. At least I am currently missing the link from the XML >"string match" definition to "XMPP entities must use this when >serializing/de-serializing XML". > >If we can make that link, then we do not need normalization. And we >probably want to clearly state that requirement in rfc6120bis, because >it is not obvious (at least for me).
I'd be quite sad if the character data would be normalized/canonicalized. Also I haven't seen this anywhere in XMPP implementations outside of JID matching. >> Also the main reason why we shouldn't ask for Unicode normalization >to >> happen is that different Unicode version have different >normalizations.> Thus if the sender normalizes with Unicode version X >and calculates >> offsets from that, then receiver normalizes with Unicode version Y >and >> determines the offsets there, they can end up in pointing to >different >> characters. > >We need Unicode agility anyway in XMPP, which I do not believe to be a >big issue. Especially since Unicode is likely to introduce lesser >changes with every future standard version. Quite (except for JIDs). This is also a reason why for example Grapheme Cluster counting would bring us a world of pain. -- Cheers, ralphm _______________________________________________ Standards mailing list Info: https://mail.jabber.org/mailman/listinfo/standards Unsubscribe: standards-unsubscr...@xmpp.org _______________________________________________
