[ratboy666]

How is GNU APL not there? It is standards compliant, 99.9% pure APL2 (per ISO standards), and is actively maintained (bugs and issues are usually turned around in a day or two). It performs quite well, and can be easily extended. I have even added memmap vectors to it to achieve even more performance (and to begin GPGPU integration).

GNU APL also supports a library version (libapl.so) which allows APL2 to be incorporated into other applications via C ffi. This is my primary use case -- interactive development followed by delivery via libapl.so.

[FractalLP]

I think it requires a more expert user. I couldn't get the manual install process to work on Ubuntu and I believe it requires MinGW or Cygwin to work on Windows (not for a beginner either). Don't get me wrong, I'm really really glad it is there.