OpenEuphoria

Re: load user defined module

• Posted by Derek Parnell <ddparnell at bigpond.com> Nov 08, 2002
• 398 views

Robert,
is this the sort of thing you are suggesting for us ? ...

include linux/ui.e as lui
include win32/ui.e as wui
include dos/ui.e as dui
.
.
.
function CreateWidget( object WidgetType, object Caption, ... )
  object lResult

  if platform() = UNIX then
    lResult = lui:CreateWidget(WidgetType, Caption, ...)
  elsif platform() = WIN32 then
    lResult = wui:CreateWidget(WidgetType, Caption, ...)
  elsif platform() = MSDOS then
    lResult = dui:CreateWidget(WidgetType, Caption, ...)
  end if

  return lResult
end function

procedure PositionCaret( object Widget, object Left, object Top)

  if platform() = UNIX then
    lui:PositionCaret(Widget, Left, Top)
  elsif platform() = WIN32 then
    wui:PositionCaret(Widget, Left, Top)
  elsif platform() = MSDOS then
    dui:PositionCaret(Widget, Left, Top)
  end if

end procedure

procedure RenderText( object Widget, object Text)

  if platform() = UNIX then
    lui:RenderText(Widget, Text)
  elsif platform() = WIN32 then
    wui:RenderText(Widget, Text)
  elsif platform() = MSDOS then
    dui:RenderText(Widget, Text)
  end if

end procedure

procedure ProcessMessages( object Widget)

  if platform() = UNIX then
    lui:ProcessMessages( Widget )
  elsif platform() = WIN32 then
    wui:ProcessMessages( Widget )
  elsif platform() = MSDOS then
    dui:ProcessMessages( Widget )
  end if

end procedure

object Window,
       Button,
       .
       .
       .

if platform() = UNIX then
  Window = lui:Window
  Button = lui:Button
  .
  .
  .
elsif platform() = WIN32 then
  Window = wui:Window
  Button = wui:Button
  .
  .
  .
elsif platform() = MSDOS then
  Window = dui:Window
  Button = dui:Button
  .
  .
  .
end if

constant MainWindow = CreateWidget( Window, "My Window", ...),
         OkayBtn = CreateWidget( Button, "Okay", ...)

PositionCaret(MainWindow, 20, 20)
RenderText(MainWindow, "Hello, World!")

ProcessMessages(MainWindow)

----------------

As you could imagine, it would not take much for this to become very hard to
maintain. Can you suggest a better approach?  Maybe something along the
lines of ...

if platform() = UNIX then
  include linux/ui.e
if platform() = WIN32 then
  include win32/ui.e
if platform() = MSDOS then
  include dos/ui.e
end if

constant MainWindow = CreateWidget( Window, "My Window", ...),
         OkayBtn = CreateWidget( Button, "Okay", ...)

PositionCaret(MainWindow, 20, 20)
RenderText(MainWindow, "Hello, World!")

ProcessMessages(MainWindow)


--------------
cheers,
Derek Parnell




----- Original Message -----
From: "Robert Craig" <rds at RapidEuphoria.com>
To: "EUforum" <EUforum at topica.com>
Sent: Friday, November 08, 2002 3:46 PM
Subject: Re: load user defined module


>
> Derek Parnell writes:
> > Rob, how would you recommend that coders deal with
> > this issue of platform-specific code, using the
> > current incarnation of Euphoria?
>
> You can use platform() to determine which platform
> you are running on. platform() is fast. It's as if you had
> coded a constant, like 1, 2 or 3. No subroutine call is made.
>
> Euphoria does not have conditional compilation built into it,
> like C does. I'd like to keep it that way. Why add
> a new concept to the language, for such a small advantage?
>
> With conditional compilation, or a preprocessor of some kind,
> you could eliminate code that's only used on another platform,
> thereby saving a few K bytes.
>
> However it's extremely rare, and getting rarer each year, for
> a program to run out of memory because it contains
> too much code. It's almost always an excess amount of data that
> causes the problem. Over time, programs grow linearly (at most)
> in size, while memory is still growing exponentially,
> so I expect this to be even less of a problem in the future.
>
> If you really want to save a few K by stripping out code,
> you can develop your own simple preprocessor in
> an hour or so.
>
> I know from coding in C, that it's more readable if all
> your nested conditional statements are at the same linguistic level,
> using if-else, rather than having two levels, with static ifdef's
> and dynamic if's mixed together.
>
> Something I could do is optimize statements like:
>           if platform()=LINUX then
>               code-block-1
>           else
>               code-block-2
>           end if
> so that no intermediate code is generated for code-block-2
> when the platform is LINUX. I'd rather do that, than introduce
> conditional compilation.
>
> Also the code above, when translated with E to C,
> will produce C code like:
>
>           if 3 = 3 then
>                code-block-1
>           else
>                code-block-2
>           end if
>
> where I know that Watcom (at least) will eliminate
> code-block-2 at compile-time.
>
> Keep in mind also, that the 2-pass binder and the translator
> will eliminate all unused routines.
>
> Regards,
>    Rob Craig
>    Rapid Deployment Software
>    http://www.RapidEuphoria.com
>
>
>
>