[shele]

Julia is much closer to Clojure than to Python in this regard, which brings back the point from above that homoiconity isn't the key ingredient

[leephillips]

How so? In julia, one problem is that you can’t redefine datatypes in the REPL. You need to restart.

[shele]

Yes, that restart is painful exactly because it interrupts the "built your program in memory while you’re writing the source code file" OP talks about.

[utxaa]

my inkling is that the more special forms the more difficult it is to repl a language. if everything is an expression not only can you eval parts of it, but that is enough to support quite a bit of extensibility sans macro.