> Jump as a concrete implementation is easy to understand (it's just math on a program counter).
This doesn't take into account what happens to memory on the stack if you jump into or out of the scope of a local variable. You can say that memory and initialization is not the implementation's problem and rely on the compiler to emit instructions that correctly adjust or initialize the stack before and after jumps. Then, yes, you get a very simple jump implementation.
But you also get an architecture that must either do stack analysis before it can safely run code, or you get an unsafe architecture. Those are both valid choices (the JVM does the former and native architectures do the latter), but there are real trade-offs with them.
A third way, that WASM does, is to say that control flow isn't simple, but that you get safe stack management for free with it.
This doesn't take into account what happens to memory on the stack if you jump into or out of the scope of a local variable. You can say that memory and initialization is not the implementation's problem and rely on the compiler to emit instructions that correctly adjust or initialize the stack before and after jumps. Then, yes, you get a very simple jump implementation.
But you also get an architecture that must either do stack analysis before it can safely run code, or you get an unsafe architecture. Those are both valid choices (the JVM does the former and native architectures do the latter), but there are real trade-offs with them.
A third way, that WASM does, is to say that control flow isn't simple, but that you get safe stack management for free with it.