OpenEuphoria

Re: No more platform(), conditional includes, conditional functions, condit

• Posted by CChris <christian.cuvier at agricultur?.?ouv.fr> May 13, 2008
• 644 views

Jeremy Cowgar wrote:
> 
> Jeremy Cowgar wrote:
> > 
> > > 
> > > ex --define=debug test.ex
> > > 
> > 
> > Yes, it can:
> > 
> > ex -Ddebug -Djohndoe -Dsimple test.ex
> > 
> 
> More over, I want to stress that this is *not* a pre-processor. A
> pre-processor
> will load the source file, scan from top to bottom looking for pre-processor
> keywords. The pre-processor would then alter the code as necessary and the
> pass
> it on to the parser.
> 
> That is not what ifdef does. Ifdef is a compile time execution keyword. It
> does
> not inject any of it's own code into the IL or C translated output. It does
> not inject any of the "FALSE" defines into IL or C code.
> 
> What this means is that the ifdef keyword causes no speed change in Euphoria
> like a pre-processor would. If you use it, you will get a performance hit
> equivalent
> to executing 1 if statement 1 time (well, per condition you have of course).
> And again, that happens at parse time, not every iteration, because it's never
> injected into IL or C. That is important to note. It's not a pre-processor.
> 
> --
> Jeremy Cowgar
> <a href="http://jeremy.cowgar.com">http://jeremy.cowgar.com</a>

I think ifdef would be even more useful with a couple predefined variables.
One I'm thinking about is "version":

ifdef version-3.1.1 then
    x=find_from(0,s,5)
else
    x=find(0,s[5..$])
    if x>0 then x+=(5-1) end if
end if

Of course, this particular code won't work because 3.1.1 doesn't recognise
ifdef, but you get the idea....

CChris