RE: Need a sanity check, please

["York, Albert" <albert.york@xxxxxxxxxxxxxx>]

My suggestion would be to break it into two or more statements. Not only
would it be easier for someone else to figure out what you are trying to do
but it would be easier to debug.

Trying to cram everything into one statement doesn't really accomplish much.
The computer ends up doing the same amount of work either way. It just makes
it harder to read and change. Even if you finally find the magic combination
which makes it work, what happens when someone tries to maintain it five
years from now?

Why jump through hoops at all? 

Albert York                          


        -----Original Message-----
        From:   rpg400-l-bounces@xxxxxxxxxxxx
[SMTP:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of
Chris_Bougher@xxxxxxxxxxxxx
        Sent:   Monday, May 24, 2004 9:56 AM
        To:     RPG programming on the AS400 / iSeries
        Subject:        Re: Need a sanity check, please


        Is there a semi-colon at the end of your statement?

        Chris Bougher



        

                              "Robert Clay"

                              <rclay@xxxxxxxxxxx        To:
<RPG400-L@xxxxxxxxxxxx>

                              m>                        cc:

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sanity check, please                                                   
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                              05/24/2004 12:12

                              PM

                              Please respond to

                              RPG programming on

                              the AS400 /

                              iSeries

        

        





        We are at V5R1 so I have to jump through hoops to get things to
work.

        Here's the situation:

        We have MONTHID  (A  6) which represents YYYYMM, where YYYY is the
year and
        MM is the month number.  Sample data would be '200404'.

        I need to do some manipulation where this value is the key and I
need to
        know the same month of the previous year.  So, I came up with this
EVAL
        statement (in free format):


        PASTMONTH = %char(atoi(%subst(MONTHID:1:4))-1) + %subst(MONTHID:5:2)


        PASTMONTH is also (A  6).


        I have the "atoi" C function prototyped:


        h BNDDIR('QC2LE')


        d atoi            PR            10I 0 ExtProc('atoi')
        d  charValue                      *   VALUE Options(*STRING)


        When I attempt to compile the program, I get this message on the
above EVAL
        statement:

        RNF0955  Item is not valid as the left-hand side of an EVAL
operation.

        Cause . . . . . :   The left-hand side of an EVAL operation must be
an item

          that can be modified.  This means that the following cannot be on
the

          left-hand side since they cannot be modified: figurative
constants;

          literals; named constants; lookahead fields; entry parameters with
the
        CONST
          keyword specified; prototype names; certain special words and
built-in

          functions. The specification is ignored.

        Recovery  . . . :   Specify a variable in the left-hand side of the
EVAL

          operation or remove the specification. Compile again.



        PASTMONTH is not a figurative constant, literal, named constant,
lookahead
        field, etc.

        It is a field in the file I am using:

        fLUMTM     UF A E           K DISK    Rename( RLUMTM : LUMTMR )
USROPN

        And, yes, I have the file opened on a prior statement due to the
USROPN
        keyword.

        Why the error?

        It's probably something simple but I just can't see it.

        Any help is greatly appreciated.


        Robert
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