# Non Standard Characters in User Names

While browsing M.SE, I came along this comment.

Out of curiosity I tried to put a comment-reply. Copy-paste is working (this time), but can't we have an autocompletion right after the @?

BTW: Which characters are allowed in user names? I got this, saying that $\LaTeX$ won't be rendered.

Would an @ be allowed? I thought about giving it a try, but I fear that comment replies won't work anymore since only 1 @ seems to be allowed in a comment, see here for some experiments.

• But "אליהו צלע" is perfectly standard... :-P – Asaf Karagila Jan 28 '13 at 22:34
• @AsafKaragila depending on your reference system that's true. To make one thing clear, this isn't not meant in any offending way at all... – draks ... Jan 28 '13 at 22:42
• Oh, I was poking fun at all you folks who don't speak fluent Hebrew.:-P – Asaf Karagila Jan 28 '13 at 22:43
• @AsafKaragila מַצְחִיק , I hope that's not wrong... – draks ... Jan 28 '13 at 22:47
• It's correct... – Asaf Karagila Jan 28 '13 at 22:49
• I should probably add that the autocompletion works fine if you type in Hebrew letters. – Asaf Karagila Jan 28 '13 at 23:00
• @AsafKaragila I should look out for user with ä,ö,ü or ß in the username and give it a try. Is hebrew written from right to left? – draks ... Jan 28 '13 at 23:04
• Yes, it is a right to left text (which makes almost all text editing annoying as hell). – Asaf Karagila Jan 28 '13 at 23:09
• Hi guys, how's it going? – Rahul Jan 29 '13 at 1:08
• @ℝⁿ. Not bad. You do realize that you are stuck with this username for 30 days, right? – user53153 Jan 29 '13 at 1:10
• @5PM: That is a burden I am willing to $\require{enclose}\enclose{updiagonalstrike}{\text{bear}}$impose on everyone who wants to reply to me. (Sorry...) – Rahul Jan 29 '13 at 1:21
• @Asaf: oh heck no. I want to see him suffer. :-) – Willie Wong Jan 29 '13 at 8:31
• BTW, I can verify that if you know how to type ℝ in unicode (I use the LaTeX input method plugin for iBus), autocompletion for @ℝⁿ.also works. – Willie Wong Jan 29 '13 at 8:40
• I just realized that there is an additional not in my first comment. Please disreagrd it... – draks ... Jan 29 '13 at 11:19
• @ℝⁿ. The new autocomplete-with-nonASCII feature automatically brings up your username. So there. – user53153 Feb 26 '13 at 2:26

In this post Atwood specified the allowed username format as ^[\w](?<!_), and helpfully added the image below. If I understand correctly, (?<!_) prohibits usernames beginning with an underscore.