Non-templated expression container?

[whart222]

Is there a standard way to store a FastAD expression in a "generic" expression object?

The BaseExpr class is templated on the derived type, which means it's not suitable for use in a class that can store any FastAD expression.

Maybe a variant of the std::any concept?

[whart222]

Alternatively, I'm wondering if there is a generic expression type that would support caching FastAD expressions in a std::vector class. Even if it wasn't as opaque as std::any, something like that seems a useful utility.