mathstackers
mathstackers
ConTeXt has a nice structure called mathstackers
in order to define new math commands in which some characters are stacked over another one. For more information refer to math-stc.mkiv.
The two command \mathover[symbol]{}{
} and \mathunder[symbol]{}{
} are built and can be used directly. However one may define one's own commands.
A typical example is when you want to put a small circle on top of a letter (as one would when defining the topological interior of a set…).
To do so we define first a new stacker named here MySymbol
, and then invoking that with \definemathover
we define two new commands \interior
and \mystarred
which can be used in math mode.
\definemathstackers[MySymbol] [voffset=-.3\mathexheight, hoffset=\zeropoint, mathclass=ord, topoffset=.4\mathemwidth, % poor man's italic correction middlecommand=\mathematics] \definemathover[MySymbol][interior]["2218] %this a small circle \definemathover[MySymbol][mystarred]["2717] % this is an asterisk \starttext Here is the new command \type{\interior{K}}: $\interior{K}$. Compare this to \type{\mathring{K}}: $\mathring{K}$. Here is the new command \type{\mystarred{K}}: $\mystarred{K}$. Here are the built-in commands \type{\mathover} and \type{\mathunder}: $\mathover[symbol]{"2217}{A}$, % 2217 is a circle $\mathover[symbol]{"2218}{A}$, % 2218 is an asterisk $\mathover[symbol]{"2219}{A}$, % 2219 is a bullet $\mathunder[symbol]{"2217}{A}$, $\mathunder[symbol]{"2218}{A}$, $\mathunder[symbol]{"2219}{A}$. \stoptext
When typeset in mkiv
one can see that the command \interior{K
} shows the letter K with a small circle above it.