But how do you implement the small, concise languages without the gotos and side-effects to begin with? You're gonna need a language with sufficient expressiven

But how do you implement the small, concise languages without the gotos and side-effects to begin with? You're gonna need a language with sufficient expressiveness and the capability to perform side-effects to do so. Implementing a new language entirely without side-effects is infeasable. Replacing GOTO with some structured variant is trivial though.