Re: ANDing and ORing conditional compilation directives

[Simon Coulter <shc@xxxxxxxxxxxxxxxxx>]

On 19/07/2008, at 9:05 AM, Rory Hewitt wrote:

> I just end up with a long list of IF, ELSE, ENDIF stuff, like below
>
> Just a thought - can you indent compilation directives - I know you  
> can with
> /COPY, even if the manual doesn't make this clear).

Nope: Compiler gives RNF0257 but it gives me that error for indented / 
COPY statements too so you might want to verify your statement.

> It's still a hassle, but
> it might make it clearer to look at
>
>  /IF DEFINED(COND1)
>     /IF DEFINED(COND2)
>        /DEFINE CONDS1AND2
>     /ELSE
>        /DEFINE COND1ONLY
>     /ENDIF
>  /ELSE
>     /IF DEFINED(COND2)
>        /DEFINE COND2ONLY
>     /ENDIF
>  /ENDIF

Like I said: messy. Although since you are setting conditions for the  
AND case it adds nothing to the basic compiler support. Testing /IF  
DEFINED(CONDS1AND2) is the same as testing nested conditions directly:
	/IF DEFINED(COND1)
	/IF DEFINED(COND2)
	    ...  do something ...
	/ENDIF
	/ENDIF

If there are definitions common to both the COND1 and COND2 cases,  
but not otherwise required, then you have to specify those  
definitions in at least two places. That's what I'm trying to avoid.

In my case the /DEFINE is done outside my control. A consumer of my  
include can /DEFINE X and get certain behaviour or /DEFINE Y and get  
other behaviour but if either X or Y is defined then I want some  
common behaviour. I'm trying to avoid having to duplicate definitions  
inside each conditional directive.

Your solution suffers from the same problem as my own: namely that  
once you've determined the appropriate condition you need to  
duplicate definitions: For example:

	 /IF DEFINED(COND1)
	 /IF DEFINED(X)
	D doStuff          PR               EXTPROC('function4')
	 /ELSEIF DEFINED(Y)
	D doStuff          PR               EXTPROC('function4')
         /ELSE
	D doStuff          PR               EXTPROC('function1')
	 /ENDIF
	 /ELSEIF DEFINED(COND2)
	 /IF DEFINED(X)
	D doStuff          PR               EXTPROC('function4')
	 /ELSEIF DEFINED(Y)
	D doStuff          PR               EXTPROC('function4')
         /ELSE
	D doStuff          PR               EXTPROC('function2')
	 /ENDIF
	 /ELSE
	 /IF DEFINED(X)
	D doStuff          PR               EXTPROC('function4')
	 /ELSEIF DEFINED(Y)
	D doStuff          PR               EXTPROC('function4')
         /ELSE
	D doStuff          PR               EXTPROC('function3')
	 /ENDIF
	 /ENDIF

Notice that for X and Y the function doStuff is mapped to the same  
external function therefore I have to code it in each conditional  
directive. What I want is:

	 /IF DEFINED(COND1)
	 /IF DEFINED(X)
	 /OR DEFINED(Y)
	D doStuff          PR               EXTPROC('function4')
         /ELSE
	D doStuff          PR               EXTPROC('function1')
	 /ENDIF
	 /ELSEIF DEFINED(COND2)
	 /IF DEFINED(X)
	 /OR DEFINED(Y)
	D doStuff          PR               EXTPROC('function4')
         /ELSE
	D doStuff          PR               EXTPROC('function2')
	 /ENDIF
	 /ELSE
	 /IF DEFINED(X)
	 /OR DEFINED(Y)
	D doStuff          PR               EXTPROC('function4')
         /ELSE
	D doStuff          PR               EXTPROC('function3')
	 /ENDIF
	 /ENDIF

Which is marginally neater and subscribes to the current syntax.  
Being able to specify:
	
	 /IF DEFINED(COND1)
	 /IF DEFINED(X) OR DEFINED(Y)
	D doStuff          PR               EXTPROC('function4')
         /ELSE
	D doStuff          PR               EXTPROC('function1')
	 /ENDIF
	 /ELSEIF DEFINED(COND2)
	 /IF DEFINED(X) OR DEFINED(Y)
	D doStuff          PR               EXTPROC('function4')
         /ELSE
	D doStuff          PR               EXTPROC('function2')
	 /ENDIF
	 /ELSE
	 /IF DEFINED(X) OR DEFINED(Y)
	D doStuff          PR               EXTPROC('function4')
         /ELSE
	D doStuff          PR               EXTPROC('function3')
	 /ENDIF
	 /ENDIF

is neater still but only because it uses less source lines.

Regards,
Simon Coulter.
--------------------------------------------------------------------
   FlyByNight Software         OS/400, i5/OS Technical Specialists

   http://www.flybynight.com.au/
   Phone: +61 2 6657 8251   Mobile: +61 0411 091 400        /"\
   Fax:   +61 2 6657 8251                                   \ /
                                                             X
                 ASCII Ribbon campaign against HTML E-Mail  / \
--------------------------------------------------------------------