On 2011-03-14 Vedran Miletić
Consider two .tex files located at http://www.inf.uniri.hr/~vmiletic/art-pre/ with same content:
context --mode=article art-pre.tex works right, context --mode=article art+pre.tex fails with
! Undefined control sequence.
system > tex > error on line 7 in file art+pre.tex: Undefined control sequence ...
Should + not be used?
Only ascii letters from [a-z] are supported as far as I know. If anything else works, be happy but it's not guaranteed. It's a bug - or maybe better - a known restriction and if I'm not mistaken it's mentioned somewhere in one of the manuals. Additionally you can find a discussion on the mailing list several weeks/months ago.
It seems to work ok without modes, but I haven't tested deeply.
As mentioned above, use it on your own risk, it may fail. Marco