Many programming language manuals start by showing how easy it is to write a "Hello world" program in that language. In APL we pride ourselves with the shortest ... start APL and type:

'Hello World'

Aplers are used to the idea of using the session as an input/output interface. The rest of the world might not consider that this qualifies as a program. In mswindows for instance a program might be defined as something we can call from the Run... dialog box or set up as a shortcut on the desktop.

To get our program into a state where we can do that requires a choice between a number of alternative routes. Using the session (as above) will work in all versions of APL, but you may want to do something more sophisticated like writing a GUI application. This can be very easy in APL, but the exact details vary from one APL vendor to another...

Here are a few possible approaches if you are using Dyalog APL:

Here are some possibilities if you are using APLX:

CategoryHelloWorld CategoryDyalog CategoryAplx