OpenEuphoria

1. Converting qbasic to Euphoria?

• Posted by Ed Davis <ed_davis2 at yahoo.com> Jul 28, 2004
• 626 views

Can the following qbasic code be easily converted to Euphoria?
Note that I am not looking for an exact translation. My goal is
to be able to use Euphoria to graph some simple algebraic
equations.  Using DOS (as opposed to Linux or Windows) is ok too.

Thanks for any help!

DIM a, b, c, x AS DOUBLE
SCREEN (12)
WINDOW (-8, 6)-(8, -6)
LINE (-8, 0)-(8, 0)   'X axis
LINE (0, 6)-(0, -6)   'Y axis
FOR x = -8 TO 8 STEP .025
    a = x ^ 2
    b = SIN(x)
    c = COS(x)
    PSET (x, a)
    PSET (x, b)
    PSET (x, c)
NEXT x

3. Re: Converting qbasic to Euphoria?

• Posted by Matt Lewis <matthewwalkerlewis at yahoo.com> Jul 28, 2004
• 618 views

Ed Davis wrote:
> 
> Can the following qbasic code be easily converted to Euphoria?
> Note that I am not looking for an exact translation. My goal is
> to be able to use Euphoria to graph some simple algebraic
> equations.  Using DOS (as opposed to Linux or Windows) is ok too.
> 
> Thanks for any help!
> 
> DIM a, b, c, x AS DOUBLE
> SCREEN (12)
> WINDOW (-8, 6)-(8, -6)
> LINE (-8, 0)-(8, 0)   'X axis
> LINE (0, 6)-(0, -6)   'Y axis
> FOR x = -8 TO 8 STEP .025
>     a = x ^ 2
>     b = SIN(x)
>     c = COS(x)
>     PSET (x, a)
>     PSET (x, b)
>     PSET (x, c)
> NEXT x

You could do this fairly easily using matheval.  You'll need to update
the grapheval.e file:

The line towards the top (add CONSTANT, VAR):

integer INVALID, DATA, GRAPH, CGRAPH, RANGE, CONSTANT, VAR

And graph_init() should look like:

procedure graph_init()
    INVALID = resolve_math_ref( "INVALID" )
    DATA = resolve_math_ref( "DATA" )
    CONSTANT = resolve_math_ref( "CONSTANT" )
    VAR = resolve_math_ref( "VAR") 

    GRAPH = reg_math_func( "GRAPH", routine_id("Graph") )
    CGRAPH = reg_math_func( "CGRAPH", routine_id("CGraph") )
    RANGE = reg_math_func( "RANGE", routine_id("Range") )

end procedure

Then try the following (uses Win32Lib):

without warning
include win32lib.ew
include matheval.e
include grapheval.e

constant 
win	= create( Window, "Graph", 0, Default, Default, 500, 420, 0 )

sequence graph, func, colors
integer GRAPH

procedure win_paint( integer self, atom event, sequence params )
	setPenColor( win, BrightWhite )
	drawPolygon( win, 1, { 10, 10, 490, 10, 490, 390, 10, 390 } )
	for i = 1 to 3 do
		drawLines( win, colors[i] & graph[i] )
	end for
	setPenColor( win, Black )
	drawPolygon( win, 0, { 10, 10, 490, 10, 490, 390, 10, 390 } )
	drawLine( win, 250, 10, 250, 390)
	drawLine( win, 10, 200, 490, 200)
end procedure
setHandler( win, w32HPaint, routine_id("win_paint"))

procedure setup()
	sequence g
	matheval_init()
	GRAPH = resolve_math_ref( "GRAPH" )
	func = {
			Parse( "x^2" ),
			Parse( "sin(x)" ),
			Parse( "cos(x)" )
			}
	
	colors = {Blue, Green, Red}
	
	graph = repeat( 0, 3 )
	SetScreen( {480, 380})
	SetOrigin({10,10})

	for i = 1 to 3 do
		g = Evaluate({ GRAPH, { func[i], "X"}, {-8, 8, 0.1, -6, 6} })
		g = floor(g[2])
		g[2] = g[1] & g[2]
		graph[i] = g[2..length(g)]
	end for
end procedure
setup()

WinMain( win, Normal )

Matt Lewis