Joy

      

        

      


      


        
Command

        

          
            

              Enter/Return
              Submit code
            

            

              Ctrl + Enter
              Newline
            

            

              Up / Down
              Browse history
            

            

              Ctrl + l
              Clear display
            

            

              Ctrl + k
              Reset toplevel
            

            

              Tab
              Indent code
            


          
        

      


      

        
Joy Reference

        

          
            

              
                Circle (with radius 50)
              
              
let c = circle 50

            

            

              
                Rectangle (with length 100, width 50)
              
              
let r = rectangle 100 50

            

            

              
                Show shapes c and r on canvas
              
              
show [ c; r ]

            

            

              
                Clear canvas
              
              
clear ()

            

            

              
                
Transformations

              		
              
            

            
            

              
                Move c to the right by 50, and up by 100
              
              
let c2 = c |> translate 50 100

            

            

              
                Move c to the right by 50, and down by 100
                

                note that we put -100 in its own parentheses.
                  we need to do this for negative numbers
              		
              
let c2 = c |> translate 50 (-100)

            

            

              
                Make c 2 times bigger
                

                note the decimal 2.0, it's a float!
              		
              
let c2 = c |> scale 2.0

            

            

              
                Make c half as small
              
              
let c2 = c |> scale 0.5

            

            

              
                Rotate a rectangle r by 18 degrees
              
              
let r2 = r |> rotate 18

            

            

              
                Rotate a rectangle r by 18 degrees, 10 times
              
              
let rot18 = rotate 18;;
let pattern = r |> repeat 10 rot18;;
show [ pattern ];;

            

            

              
                Rotate a rectangle r by 18 degrees and scale it by 0.8 in one transformation
              
              
let tr = compose (rotate 18) (scale 0.8)

            

            

              
                Rotate a rectangle r by 18 degrees and scale it by 0.8, 10 times
              
              
let tr = compose (rotate 18) (scale 0.8);;
let pattern = r |> repeat 10 tr;;
show [ pattern ];;

            

            

              
More shapes!

              
            

            

              
                Ellipse (with x-radius 100, y-radius 50)
              
              
let e = ellipse 100 50

            

            

              
                Line (from origin to (-50, 50))
              
              
let l = line (point (-50) 50)

            


          
        

      

      

        
A compiler from OCaml bytecode to Javascript.

        
It makes OCaml programs that run on Web browsers. It is
          easy to install as it works with an existing installation of OCaml,
          with no need to recompile any library. It comes with bindings for a
          large part of the browser APIs.

        
This web-based OCaml toplevel is compiled using Js_of_ocaml.

        
Command

        

          
            

              Enter/Return
              Submit code
            

            

              Ctrl + Enter
              Newline
            

            

              Up / Down
              Browse history
            

            

              Ctrl + k
              Reset toplevel
            

            

              Tab
              Indent code
            


          
        

        
Try to execute samples

        

        
        
See the generated javascript code