[sabauma]

Chez is an AOT compiler. I am not sure how the REPL operates, but I believe it just compiles expression on the fly before executing them. I suppose you could characterize that as JIT compilation, but the optimizer does not make use of any runtime profiling information. Racket's "JIT" is similar in that code is generated for a function when it is first called, but the optimizer is run on the bytecodes of the program before anything is run.

[fiddlerwoaroof]

In Common Lisp it's fairly common for eval to compile the code and then execute it. For example, sbcl's repl usually compiles the entered expression and then executes it: although recent versions also provide an interpreted mode.

[sedachv]

> I suppose you could characterize that as JIT compilation, but the optimizer does not make use of any runtime profiling information.

That is JIT compilation. AFAIK James Gosling started using the phrase in the 1990s to pretend that it was something novel and to ignore the fact that that is how Lisp and Smalltalk systems have always worked. This is really confusing today because a lot of people started using "JIT" to be synonymous with dynamic recompilation techniques like tracing.

[throwaway7645]

Ah. So if Racket uses the Chez Compiler it could use it for the REPL as well.