Re: /FREE RPG compiler errors

["mlazarus@xxxxxxxx" <mlazarus@xxxxxxxx>]

Barbara,

"M. Lazarus" wrote:
> ...
>   I'm not advocating using it for new code, but when converting old code
it
> would be *very* helpful.
> ...

> Mark, the reason MOVE and its friends aren't included in /free is that
we didn't think the MOVE opcode was the best choice for nearly all the
places it's currently used.  In the places where MOVE is a natural
assignment, EVAL works the same.

 For new code, I agree.


> /free is more intended for new code than for converted old code.  ("Old
code" is often code that has not been significantly changed since it was
converted from RPG III.)  We don't expect or want people to do any
wholesale conversions on their code to /free.

 Not having direct opcode conversion for all (major) opcodes directly
PREVENTS this, as even a simple tool (like CVTRPGSRC, which many people
used to get a flavor of the RPG IV syntax) could not be created easily.

> Here are a couple of reasons why I think it's not wise to convert "all"
existing code to /free:

> 1. As someone already pointed out in this thread, the bifs often don't
work exactly the same way as the opcodes.  Doing a conversion would
usually require some recoding and would always require a lot of testing.

 I think that that would be less of an issue, since most do work the same.


> 2. The issue with the icky replacement for MOVE say by %SUBST and %EDITC
would be much less likely to come up with new code as with converted RPG
code.  Trying to convert code line-by-line rather than
section-by-section is where the problems arise.  Why is that MOVE trying
to put a numeric value into the second two bytes of A, anyway?  Maybe it
would be better if A was a data structure with a zoned subfield.  If
it's part of some general buildup of the value of A, maybe several MOVE
lines dealing with A could be replaced by one concatenation expression. 
(Similar to the way two MOVEAs and a loop can often be replaced with one
string expression.)

 The MOVEx family is the big one.

 A typical scenario:  Customer requests some additional edit checking or
functionality.  I find the subroutine, want to change it to /free w/ a
minimum of hassle and add the new code.  The MOVE issue requires a lot of
research to make sure an EVAL won't break existing code.  Conclusion? 
Forget it!  Just stick w/ the existing format and be done w/ it.  

 I just think that this particular decision is one reason that /free is not
being adopted as quickly as it can.  I guess time will tell.

 -mark


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