Web assembly is the first time a binary assembly has been adopted as an open web standard. What do you propose as an alternative safe sandbox for other language

Web assembly is the first time a binary assembly has been adopted as an open web standard. What do you propose as an alternative safe sandbox for other languages? Large quantities of code can already be compiled to WASM. Since Unison works best with pure functions, most system interfaces would presumably be emulated. This emulation is already possible with Browsix.