Add visualizer for Expressions

[adishavit]

Eigen is based on expression decomposition.
When using auto A = B*C, A will be an "intermediate" expression syntax tree.
It would be great if the visualizer could call A.eval() to get the actual matrix to display.
Is this possible?

[cdcseacave]

As far as I know it is not possible, but pls check the natvis format docs for that.

[adishavit]

It is possible to call eval() in the debug and Immediate windows, so I was hoping it is possible to do it on the natvis level.
TBH, the docs are a bit too dense for me to figure out if you can run arbitrary debug scriptable code from it.