newRPL - build 1255 released! [updated to 1299]

[The Shadow]

Your system in principle would allow for equations involving both real (or complex) and matrix variables. The problem is this will cause the number of rules to balloon.

Maybe your original idea of having a "matrix mode" set by flags is the way to go... In that mode, scalar variables are treated as matrix variables - in essence, just multiplying them by the identity matrix. Rather than a special symbol for the zero matrix for example, you just treat it as the scalar 0 times I. Does that make sense?

As for the size of the identity matrix... You could treat it as a global variable, the way modular bases are now?

EDIT: Your matrix variables could include further settings: Diagonal, and "multiples of the identity matrix". Possibly even triangular.