So let's say I have a function that needs :name and :addr and it adds a new field calls :name+addr. Now in most (all?) statically typed languages I would have to say that this function takes a "name and addr" and returns "name, addr, and name+addr". So I have a type conversion, right? If the time comes that I need to modify these types, I have to do some sort of refactor.

In Clojure we'd just take a hash map and add a new k/v pair to the hash map we get. Any hash map will work, as long as it has the proper entries, and we'll just add a new entry to that. So if the time comes that I want to call this function with a "company" instead of a "person", it just works, as long as I have the proper keys. And to help check this sort of stuff we do have spec (https://clojure.org/about/spec).

TL;DR -- my belief having programed in both static and dynamic languages is that deep refactoring is primarily driven by the inflexibility of static types.

Clojure and Haskell are two almost completely different beasts. Thanks to clojure's simplicity (as a dialect of lisp), it could BECOME haskell if you wrote the DSLs for it, but the reverse is much harder, I would think.

Eta is not looking to convince clojurists to use haskell on the jvm instead of clojure, it's (most likely, I don't maintain the project) to enable those who want to use haskell but want to also use the JVM to do so.

Regardless of whether Haskell is a better choice for your project or clojure is, the eta team (or any other team for that matter) is under no obligation to find that out for you, or even to make your search any easier. That's your job -- if clojure still fits your needs and doesn't have any glaring issues, absolutely use it.

I think the statement is almost axiomatic. Lisp is multi-paradigm, by way of simplicity/choices not being made for you. Haskell is decidedly functional (which is something I love about it). Making a more specific thing into a less specific thing (while possible in this case), seems like a more difficult task than molding the clay that is LISP to look like haskell.

Clojurescript is just wonderful. I'm not even sure a Haskell-like language that compiles to JavaScript (Elm, PureScript, GHCJS) with really good tooling can beat it, though I haven't tried. Would be an interesting experiment to do a comparison by writing the same app in all the languages.

Just compare:

    foo.bar(baz)

    (.bar foo baz)

Sure CommonLisp has a ton of parens, but thats CL and it has its own set of issues.

One more example:

    Runnable foo = new Runnable() {
      Object run(Object bar)
      {
        return bar;
      }

    }

    (reify Runnable
      (run [bar]
        bar))