[TeMPOraL]

Can you recompile a function on a running program and have it pick up the new definition? Can you change a class at runtime, and then adjust already existing objects to match the new definition in a controlled way, without data loss? Can you forget to define a function, or initialize a variable, only to be allowed by the debugger to provide a new definition / value on the fly and continue execution?

Those are some examples off the top of my head, but the general point is that unlike mainstream languages, Lisp languages evolved into environment for interactive construction and modification on a continuously running program, which is a bit different way of working than the regular write-compile-run cycle.

[aerique]

Some, most?, of the things you mention are available in other languages but they generally do not come together so well and they feel clunky.

I think it's not so much whether the features exist in other languages since we all know they can be added but the whole being more than the sum of its parts.

[didibus]

I find Clojure to be practical today, and it supports most of those. I believe it lags a little behind CLs development features, but since it tends to force immutable and referentially transparent code, I find that helps too. Since swapping things out is trivial in those cases.

[Arelius]

With Javascript as an example, it can indeed be used in this fashion, as I expect also Python. But the key difference is the community of CL is this is a standard way of working, and the tools are built around this.