[Standards] Proposed XMPP Extension: Styling

Marvin Gülker m-guelker at phoenixmail.de
Mon Nov 6 20:08:58 UTC 2017

The XEP defines requirements like "MUST be displayed in italics" (§6.5)
or "MUST be displayed with a horizontal line through the middle (strike
through)" (§6.6) that immediately map to the user interface and are not
possible to implement in a terminal client on most terminal emulators. I
don't see why a terminal client should be excluded from supporting this
XEP -- it might be able to show elements by other means than the XEP
author imagined (e.g., using colour instead of italics; check how man(1)
copes with italics). The wording should be changed to reflect the
semantical meaning and not the visual outcome.

In that regard, the Markdown-inspired approach is bad at conveying the
semantical meaning anyway. It just comes from the wrong end -- it says
"make this bold" or "strike this through", but it does not allow me as
author to say "emphasize this", "this is a person's name", or "this is
outdated". It forces a visual output where it should rather leave the
means by which a semantical meaning is conveyed to the client developer.
Take an extreme example: a client that does not output messages
visually, but auditive by reading them out, which may well be a useful
feature for visually impaired people. Since we cannot know all possible
kinds of client UIs in advance, we should try to not interfer with the
developer's UI as far as possible.

Another point of critique we already heard earlier on this mailinglist:
anything that's not based on XML requires the application developer to
either implement a new parser for the format himself or add a dependency
on an external parser. It looks like this XEP is Markdown for the sake
of using Markdown, whereas a more efficient solution would rely on the
tools already available. Not using something XML-based in a XEP's format
also creates a precedence case from which we don't know where else it
will come back at us when other XEPs are made.


Blog: https://www.guelkerdev.de

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