On Thu, 18 Mar 2021, Weber, Matthias wrote:

Hello,

Is it possible to nest cases in math, like so:

In principle, it should be. But we never tested this and I suspect that there is some macro which doesn't get initialized correctly in nested cases.

\starttext \startformula x= \startcases[align={right,left},distance=3pt] \NC a \NC = \startcases[align={right,left},distance=3pt] \NC 1 \NC \text{case a1} \NR \NC 2 \NC \text{case a2} \NR \stopcases \NR \NC b \NC = \startcases[align={right,left},distance=3pt] \NC 3 \NC \text{case b3}\NR \NC 4 \NC \text{case b4}\NR \stopcases \NR \stopcases \stopformula \stoptext

I get an error about a missing $ when I try a nested start/stop-cases.

The missing $ error is because the cases environment uses two column separators (for the second column): \NC for "normal text column" and \MC for "math column". This is so that in the typical case, you can just use: \startformula x = \startcases \NC 1 \NC case $a_1$ \NR \NC 2 \NC case $a_2$ \NR \stopcases \stopformula So, in your cases, you should have used: \starttext \startformula x= \startcases[align={right,left},distance=3pt] \NC a \MC = \startcases[align={right,left},distance=3pt] \NC 1 \NC case a1 \NR \NC 2 \NC case a2 \NR \stopcases \NR \NC b \MC = \startcases[align={right,left},distance=3pt] \NC 3 \NC case b3\NR \NC 4 \NC case b4\NR \stopcases \NR \stopcases \stopformula \stoptext But, something goes wrong and that doesn't work either (with a different error message). I suspect that something is not getting initialized correctly at \startcases and will look into that. Aditya