Classes in functions

[Niels Henrik Bruun]

Hi
According to the code below it seems like you can not use classes as arguments to or inside functions.

Is that true? Or am I doing something wrong?

If it is true is there then a workaround for it?

cls
mata
    mata clear

    
    class coord {
            real scalar    x, y
            real scalar    length(), angle()
    }

        real scalar coord::length()
        {
                return(sqrt(x^2 + y^2))
        }

        real scalar coord::angle()
        {
                return(atan2(y, x)*360/(2*pi()))
        }

    
    void test1(class coord scalar c)
    {
        return(c.length())
    }

    void test2(real scalar x, y)
    {
        real scalar l
        class coord scalar c
        
        c = coord()
        c.x = x
        c.y = y
        l = c.length()
        return(l)
    }

    c = coord()
    c.x = 4
    c.y = 3
    c.length()
    
    test1(c)
    /* From the Results window
    :         test1(c)
                     test1():  3258  l[1,1] found where void required
                     <istmt>:     -  function returned error
    r(3258);
    */
    
    test2(5, 12)
    /* From the Results window
    :         test2(5, 12)
                     test2():  3258  l[1,1] found where void required
                     <istmt>:     -  function returned error
    r(3258);
    */
end

[Hua Peng (StataCorp)]

Your test1() and test2() are declared as returning void but should be declared as returning real scalar.

[Niels Henrik Bruun]

Ah
Now everything is working , also:

:     class coord scalar test4(class coord scalar c, real scalar x, y)
>     {
>         c.x = x
>         c.y = y
>         return(c)
>     }

:     
:     c = coord()

:     c = test4(c, 5, 12)

:     c.length()
  13

So it was just me.

Thank you very much