What makes a good REPL?
With fast compiling languages a unit test is not for off from being a REPL. In Java I use JUnit as a REPL.<p>Actually I prefer unit tests over a REPL the same reason I prefer bash scripts over one liners or SQL scripts instead of typing into the interpreter... I don&#x27;t like the ephemeral nature of REPLs.<p>Also with true REPLs unlike the debug unit test approach I mention with Java you really need the language to be dynamic. I&#x27;m not entirely sure why but static type languages are not very good at allowing code modification while running (I mean I have ideas but I don&#x27;t know precisely if there is an actual theoretical limitation).<p>I guess I prefer static analysis over the complete ability to modify the code base while running.<p>Only add my 2 cents because the article doesn&#x27;t mention any negatives to REPLs.