BIFs requiring constants = frustrating

%kds - number of keys to use has to be a constant
%dec - length and decimal positions have to be constants
%editc - edit code has to be constant

I'm working with amounts that I'm writing to XML. They can have differing decimal precision based on the client processed. I thought, wonderful, I can create a procedure, pass in some parameters, and simply insert those parms into a statement to format my return value. If only it were so easy. But why isn't it? What is the purpose of making BIF parms requiring constant values? Where is the flexibility in that? I suppose it may be easier on the RPG developers, but is it better for the language?

Info about my example. Amounts are already rounded to the needed precision. Also, we go out to 6 decimals, I cut the example down to only going out to two decimals.

So in my example, instead of being able to code:
rtnAmount = %trim( %editC( %dec( Amount: LEN_Amount: w_DecPos ): EditCode: *CurSym);

I have to code:

20983 Select;

20983 When w_DecPos = 0;
20983 Amt0Dec = Amount;

20983 Select;
20983 When EditCode = 'A';
20983 rtnAmount = %trim( %editc( Amt0Dec: 'A': *CURSYM ) );
20983 When EditCode = 'B';
20983 rtnAmount = %trim( %editc( Amt0Dec: 'B': *CURSYM ) );
20983 EndSl;

20983 When w_DecPos = 1;
20983 Amt1Dec = Amount;

20983 Select;
20983 When EditCode = 'A';
20983 rtnAmount = %trim( %editc( Amt1Dec: 'A': *CURSYM ) );
20983 When EditCode = 'B';
20983 rtnAmount = %trim( %editc( Amt1Dec: 'B': *CURSYM ) );
20983 EndSl;

20983 When w_DecPos = 2;
20983 Amt2Dec = Amount;

20983 Select;
20983 When EditCode = 'A';
20983 rtnAmount = %trim( %editc( Amt2Dec: 'A': *CURSYM ) );
20983 When EditCode = 'B';
20983 rtnAmount = %trim( %editc( Amt2Dec: 'B': *CURSYM ) );
20983 EndSl;
20983 EndSl;

If I'm missing something and there's an easier way to do what I'm doing, please let me know.

Thanks,

Kurt Anderson
Sr. Programmer/Analyst
CustomCall Data Systems
Madison, WI