RE: /FREE RPG compiler errors

-----Original Message-----
From: rpg400-l-bounces@midrange.com
[mailto:rpg400-l-bounces@midrange.com]On Behalf Of Peter Dow
Sent: Monday, February 10, 2003 10:24 PM
To: RPG programming on the AS400 / iSeries
Subject: Re: /FREE RPG compiler errors

>I believe Gary's point was that it's readable, but to determine what a MOVE
>opcode actually doing, you have to know the definitions of Factor 2 and the
>Result field, but with the /free method it becomes apparent just by looking
>at the EVAL statement.

Hi Peter,

In mine and dare I say Bjarne Stroustrup's opinion Gary is wrong on this
point.  One of the objectives of good program design is to abstract away as
many of the underlying details of the objects of a program as possible.   In
C++, the action of "A = B" depends on what A and B are.  All the coder knows
( and needs to know ) is that the value of B will be assigned to A.   Same
thing with the RPG MOVE ( should be COPY but who wants to quibble? ).   When
you see a MOVE stmt, you know that the value of factor 2 is being copied
right justified to the result variable.


>Also, you talk about removing the MOVE opcode.  If you mean it's been
>removed from RPG IV, that is not the case.  If you mean it's been removed
>from the /free syntax, it was never in it.  If you mean IBM plans to remove
>it from the language, I doubt it.

The problem with not including MOVE in /free is that IBM did not provide the
ability to write a proc version of MOVE.  What is needed are data pointers
in RPG, that is a pointer that also contains the attributes of the data
pointed to.  Or an OPDESC that actually has a complete set of operand
description information.  Or allow programmers to write their own BIFs.

Steve