OpenEuphoria

Re: Multiple includes

• Posted by kbochert at copper.net Nov 11, 2003
• 475 views

On 11 Nov 2003 at 13:08, C. K. Lester wrote:

> >
> Whoa! When did we get class types?
> 
> Can we do something like
> 
> class Rect
> atom x1, x2, y1, y2
> 
> classfunction Resize(atom way, atom perc)
>     if way = RECT_EXPAND_HORIZONTAL then
>        x2 *= perc
>     elsif way = RECT_EXPAND_VERTICAL then
>        y2 *= perc
>     else
>        x2 *= perc
>        y2 *= perc
>     end if
> end classfunction
> 
> end class


In Bach, yes, with slightly different syntax:

class Rect
atom x1, x2, y1, y2
endclass

method Resize(atom way, atom perc)
    if way = RECT_EXPAND_HORIZONTAL then
       .x2 *= perc
    elsif way = RECT_EXPAND_VERTICAL then
       .y2 *= perc
    else
       .x2 *= perc
       .y2 *= perc
    end if
end method

1) the class declaration only contains the data.

2) methods are attached to the most recently- refined class

3) class members are referenced with a leading '.'

4) a method may or may not return a value. A returned value
may be ignored.

More refinements:

class Rect
atom x1 = 0, x2 = 0, y1, y2
constant HORIZONTAL = 1,
              VERTICAL = 2
endclass

method Resize(atom perc, way = 0)
    if way = .HORIZONTAL then
       .x2 *= perc
    elsif way = .VERTICAL then
       .y2 *= perc
    else
       .x2 *= perc
       .y2 *= perc
    end if
end method
...
Rect myrect   -- x1 and x2 are initialized to 0
myrect.x2 = 3
myrect.y2 = 3
myrect.Resize(5)    -- resize both x and y
myrect.Resize(3, Rect.VERTICAL)

Karl Bochert