1. Help creating procedures
- Posted by dstanger at belco.bc.ca
Jul 19, 2001
Hello all,
I am writng a program in DOS32 that displays bitmaps a lot and I am
attempting to write two procedures that will make this task easier to code.
My first procedure allows me to load a bitmap and display it at a certain
point on screen with one line of code:
procedure image(sequence name, integer x, integer y)
integer error
object bitmap
bitmap = read_bitmap(name & ".bmp")
error = sequence(bitmap)
if error = 0 then
puts(1, "Error loading bitmap")
abort(0)
else
all_palette(bitmap[1] / 4)
bitmap = bitmap[2]
display_image({x,y}, bitmap)
end if
end procedure
Now I can call a bitmap and display it like so:
image("c:\\euphoria\\bitmaps\\test", 100, 100)
What I want to do now it have another procedure called address that would
allow me to list the address seperately and have image() use that each time
so that I do not have to type it repeatedly. Something like:
procedure address(sequence where_is_it)
end procedure
Used like so:
address("c:\\euphoria\\bitmaps\\")
My problem is that when I try to place where_is_it in procedure image() I am
informed that where_is_it has not been declared. I have been trying all
sorts of things but nothing solves the problem. This error is resulting
before the program even runs.
Any help?
Thank you,
David S.
2. Re: Help creating procedures
- Posted by euman at bellsouth.net
Jul 19, 2001
> > I am writng a program in DOS32 that displays bitmaps a lot and I am
> > attempting to write two procedures that will make this task
> > easier to code.
> > My first procedure allows me to load a bitmap and display it
> > at a certain
> > point on screen with one line of code:
> >
> > procedure image(sequence name, integer x, integer y)
> >
> > integer error
> > object bitmap
> >
> > bitmap = read_bitmap(name & ".bmp")
> > error = sequence(bitmap)
> >
> > if error = 0 then
> > puts(1, "Error loading bitmap")
> > abort(0)
> > else
> > all_palette(bitmap[1] / 4)
> > bitmap = bitmap[2]
> > display_image({x,y}, bitmap)
> > end if
> >
> > end procedure
> >
> > Now I can call a bitmap and display it like so:
> > image("c:\\euphoria\\bitmaps\\test", 100, 100)
> >
> > What I want to do now it have another procedure called
> > address that would
> > allow me to list the address seperately and have image() use
> > that each time
> > so that I do not have to type it repeatedly. Something like:
> >
> > procedure address(sequence where_is_it)
> > end procedure
> >
> > Used like so:
> >
> > address("c:\\euphoria\\bitmaps\\")
> >
> > My problem is that when I try to place where_is_it in
> > procedure image() I am
> > informed that where_is_it has not been declared. I have been
> > trying all
> > sorts of things but nothing solves the problem. This error is
> > resulting
> > before the program even runs.
>
> I suspect that the problem is that the "address" procedure has been defined
> after the "image" procedure. Euphoria is a bit simplistic in this regard,
> unlike some other languages. Euphoria can only use routines if it has
> already seen their definition earlier in the source code.
>
> Thus ...
> procedure aa()
> end procedure
> procedure bb()
> aa()
> end procedure
> is okay ...
AND THIS IS OK TOO!
integer aa_int
aa_int = 0
procedure bb()
call_proc(aa_int, {})
end procedure
procedure aa()
bb()
end procedure
aa_int = routine_id("aa")
aa()
or,
bb()
Euman
euman at bellsouth.net
> But ......
> procedure bb()
> aa()
> end procedure
> procedure aa()
> bb()
> end procedure
> aa()
>is not okay. You may have to manually rearrange your source code so that
>Euphoria stops complaining.
> -----------
> cheers,
> Derek Parnell
> Senior Design Engineer
> Global Technology Australasia Ltd
> dparnell at glotec.com.au
>
> ---------------------
3. Re: Help creating procedures
- Posted by irvm at ellijay.com
Jul 20, 2001
On Thursday 19 July 2001 21:53, Derek Parnell wrote:
> I suspect that the problem is that the "address" procedure has been defined
> after the "image" procedure. Euphoria is a bit simplistic in this regard,
> unlike some other languages. Euphoria can only use routines if it has
> already seen their definition earlier in the source code.
I am always puzzled why this is a problem for anyone.
Many languages require definitions of variables, functions and procedures
*before* they are called. I may not always write my code in the order that
it appears in the source file, but it's just a matter of hitting the page-up
key a couple of times to put things where they belong.
To do otherwise is like my building a house for you, and after I'm finished,
learning how to cut lumber.
Regards,
Irv
