RE: The pulse of the Nation (Was: Please vote for Syntax check in /FREE!)

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx]On Behalf Of Hans Boldt
Sent: Friday, October 17, 2003 12:28 PM
To: rpg400-l@xxxxxxxxxxxx
Subject: Re: The pulse of the Nation (Was: Please vote for Syntax check
in /FREE!)


Steve Richter wrote:
>
> In this case the compiler's response is that operator+ is ambiguous. To
> clear up the ambiguity, the programmer could be allowed to specify the
> return type, that is the full signature of the function:
>      <char>getMonth(x) + <char>getMonth(y)
>

Hans thought he had me and said:

>But then, what's the difference between coding:
>  <char>getMonth(x) + <char>getMonth(y)
>
>   and:
>
>   getMonthAsChar(x) + getMonthAsChar(y)
>
>
>  eh?

in the first version, the explicit return type is only needed if the
operator+ is ambiguous. ( and if the procs are only overloaded on primitive
return types like char and bin. in practice, one proc may return a string,
others would return different data structures. In such a case, operator+ is
not ambiguous. )

in the 2nd version, the "AsChar" always has to be typed out and effectively
locks in place a dependency ( between the proc and the lhs of the
expression ) that could hinder future changes to the code.

  CharFld = getMonth( x ) ;
can be changed later on in the app dev cycle to:
  DecFld = getMonth( x ) ; // no problem!

with less chance of error than:
  CharFld = getMonthAsChar( x ) ;
is changed to:
  DecFld = getMonthAsChar( x ) ;  // possibly not flagged as error
                                  // by the compiler.

( hope you dont feal badgered.  I'm interested in the subject. )

Anyway, I am thinking that the need for procedure overloading may just be a
placeholder for the need for namespaces.  Where two procs, in two different
include files, are allowed to have the same name because their arguments are
different.  In such a case, namespaces would be a better way to allow the
procs to have the same name:

Using overloading to distinguish two procs:
     PrintOrder( PurchaseOrder_DataStruct ) ;
     PrintOrder( CustOrder_DataStruct ) ;

Better to use namespaces:
     purchasing::PrintOrder( arg1 ) ;
     customer::PrintOrder( arg1 ) ;

-Steve