It’s hard to generate efficient code ahead-of-time because the compiler doesn’t know what the types of values will be, so it has to emit very general code that

It’s hard to generate efficient code ahead-of-time because the compiler doesn’t know what the types of values will be, so it has to emit very general code that can cope with all possibilities at the expense of performance. A just-in-time compiler has access to this type information because it’s executing at runtime, so it’s able to generate more efficient code which only works in the more specific situation that is actually happening right then. See Natalie [0] for a work-in-progress Ruby compiler which works ahead of time. It’s a super cool project but it’s just for fun [1] so I don’t believe it’s trying to compete on performance. [0] https://natalie-lang.org/ https://natalie-lang.org/ [1] https://justforfunnoreally.dev/ https://justforfunnoreally.dev/