How should this language be implemented?

There is no best answer here and the tree does not produce one. Each leaf names what the strategy actually guarantees, what it costs, and the strategy you would pick instead if the constraint that led you here turned out to be soft. Start from the hardest constraint, not from the language you like.

How should this language be implemented?Which optimization applies to this code?Should I build a DSL?

What is the hardest constraint on how these programs must run?

Pick the one you would refuse to trade away. If two feel equally hard, ask which one has a deadline attached; the other one is negotiable.