I'm not an expert in either language, but have played with both and APL is much easier to experiment with and less hard for me to grok than Haskell. Both have REPLs, but there is a lot of additional ceremony with Haskell (for good and bad). I don't see a huge amount of the APL crowd going to Haskell. Yeah it has terse operators and points-free, but it is more the sum of the whole kind of thing.
I agree and don't mean to imply Haskell has an out-of-the-box K/APL experience. More that with it's syntactic flexibility, one can imagine offering a k-like DSL/library in Haskell which would then give you access to its ecosystem, freely distributable apps, etc.
No problem and I like you're thinking, but honestly just want a free and open source APL or K language that is part of a lightweight download (a few MB) that can also create zero install executables that bundle the interpreter. There are a lot of toy projects out there, but nothing really close to what I want. I'd build it myself if I had the time and was significantly more talented :).
