Am 09.05.2015 um 15:00 schrieb Hans Hagen <pragma@wxs.nl>:

On 5/9/2015 1:56 PM, Wolfgang Schuster wrote:

Am 09.05.2015 um 13:46 schrieb Hans Hagen <pragma@wxs.nl
<mailto:pragma@wxs.nl>>:

On 5/9/2015 2:03 AM, Aditya Mahajan wrote:
Hi,

There is a question on TeX.SX asking how to change the font of \sin,
\cos, etc.

http://tex.stackexchange.com/q/243893/323

I looked at the code, and there does not appear to be an easy solution.
The \mathfunctionlabeltext command has \mathupright hard coded.

One option is to keep this configurable using \setupmathematics, perhaps
mfunction=(normal|italic|sans).

In any case, I think that the current implementation is a bug. The
default font for mathfunctionlabeltext should be typeset in the bodyfont.

this is evil (as it's unpredictable, so no support for side effects):

% \prependtoks \rm \to \everymathematics

Is there no better way to use upright letters in math except the line above?

for functions one can now use:

\setupmathematics
[functionstyle=\rm]

and for other changes the normal alphabet changing commands. For text one has the text commands. Keep in mind that in the regular math stream we don't think of fonts but of alphabets

The bold and italic symbols/letters aren’t a problem because the have their own unicode points but for the normal upright characters there should be proper key (like the lcgreek and ucgreek keys) which prevent ConTeXt to make them into italic characters. The \everymathematics hack works but isn’t very nice.