By using the APL's built in GUI interface we can build a Hello world form.

HelloWorld;ref;btn;myFnt
⍝ Build up a GUI and display "Hello world" in a button on a Form

 ref←⎕NEW⊂'Form'                      ⍝ Create a form with default parameters
 ref.Caption←'Hello World with APL'   ⍝ Set the caption
 ref.Coord←'Pixel'                    ⍝ Deal with pixels

 myFnt←⎕NEW⊂'Font'                    ⍝ Create a font
 myFnt.Pname←'Arial Black'            ⍝ Which one
 myFnt.Size←48                        ⍝ Setting the font size

 btn←ref.⎕NEW⊂'Button'                ⍝ Create a button
 btn.Caption←'Hello World'            ⍝ Set the caption of the button
 btn.Posn←0 0                         ⍝ Set the position of the button
 btn.Size←ref.Size                    ⍝ Make the button the same size as the form
 btn.FontObj←myFnt                    ⍝ Associated the font with the button
 btn.onSelect←1                       ⍝ Interrupt when button is pressed

 ⎕DQ'.'                               ⍝ Give control to the user

By setting the system variable ⎕LX to 'HelloWorld' we make sure that this code is executed automatically as soon as our program is loaded by APL.

This program will result in this form:

attachment:helloworld.jpg

To make our program runnable we can select the File|Export menu command to produce a bound executable whose name we can type into the Run... dialog.

attachment:makehelloworld.jpg

CategoryHelloWorld CategoryDyalog