On Wed, 17 Aug 2016, Mikael P. Sundqvist wrote:

Hi!

look at the output of this (attached)

\definemathcommand [D] [nolop] {\mfunction{D}} \starttext Compare $\D f$ with $\mfunction{D}f$. \stoptext

In the \D, the D is lowered a bit. I think it should not be, or else I misuse something. If so, how should I define my own operator (I found this example on the wiki).

This is a "feature" of \mathop. \definemathcommand [D] [nolop] {\mfunction{D}} \starttext Compare $\D f$ with $\mfunction{D}f$ and $\mathop{\mfunction{D}}f$. \stoptext If the argument of \mathop is a single character, \mathop centers the glyph on the math axis (This is useful for \sum, \int, \prod, etc.). To circumvent this, use: \definemathcommand [D] [nolop] {\mfunction{D}\kern\zeropoint} Aditya