Extend prototyped procedure calls with "keyword parameters"

SQL has the nice feature, to use optionally use keyword parameters instead of positioned parameters. My idea is, also extend RPG prototyped procedure calls with the option to use keyword parameters.

Imagine the following procedure prototype:

dcl-pr myProc;
  parm1 char(1) const;
  parm2 char(1) const options(*nopass:*omit);
  parm3 char(1) const options(*nopass:*omit);
end-pi;

Today we can / have to call it like in the following examples:

myProc('A':'B':'C');
myProc('A');
myProc('A':'B');
myProc('A':*omit:'C');

And this should still be possible.

I propose to extend the RPG syntax, to also allow called like the following:

myProc(
  parm1 => 'A',
  parm2 => 'B',
  parm3 => 'C'
  // all parameters supplied
);
myProc(
  parm1 => 'A'
  // 2nd and 3rd parameter is ommitted
);
myProc(
  parm1 => 'A',
  parm2 => 'B'
  // 3rd parameter is ommitted
);
myProc(
  parm1 => 'A',
  parm3 => 'C'
  // 2nd parameter is ommitted
);
myProc(
  parm2 => 'B',
  parm3 => 'C',
  parm1 => 'A'
  // parameters "out-of-order"
);

Of course when a non-omissible parameter is omitted, the compiler still has to produce an error message. Also if any data type mismatch occur.

This new syntax would have the following advantages:

1. better readability

2. still backward compatible as omitted parameters can be checked with %passed(...)

3. no need for new prototypes - but not possible of unnamed parameters are used in the prototype

4. inline with SQL syntax

5. inline with other modern languages like Python, Ruby or Swift