Indeed, we have used `Expr` and the `ReflectedDefinition` attribute internally in F#. However, if the user is capable of giving you literally anything, you'll s

Indeed, we have used `Expr` and the `ReflectedDefinition` attribute internally in F#. However, if the user is capable of giving you literally anything, you'll struggle to optimise it! We've found it important to artificially restrict what the user can give us, by explicitly modelling the domain.