Date: Thu, 4 Mar 1999 11:48:56 +1100
Reply-To: Thomas Rick <rthomas@WOOLWORTHS.COM.AU>
Sender: "SAS(r) Discussion" <SAS-L@UGA.CC.UGA.EDU>
From: Thomas Rick <rthomas@WOOLWORTHS.COM.AU>
Subject: Re: MACRO Invocation - Solution
Content-Type: text/plain
Thanks to Wolf, Thomas, Nancy B, Nancy P and Ian for their help in solving
my problem.
The problem was not one but two nested macros that created a macro variable
I. Neither was declared as local. Declaring the variables as local in all
the macros using %LOCAL fixed the problem.
I'm off to re-read the manual to get all this stuff about macro referencing
back into my head - I thought I knew it once :o)
Thanks again for the help - this list is great!
Regards,
Rick.
> -----Original Message-----
> From: WHITLOI1@westat.com [SMTP:WHITLOI1@westat.com]
> Sent: Thursday, March 04, 1999 2:46 AM
> To: Thomas Rick; SAS-L@UGA.CC.UGA.EDU
> Subject: Re:MACRO Invocation
>
> Subject: MACRO Invocation
> Summary: Declare local variables, use CALL EXECUTE for looping
> Respondent: Ian Whitlock <whitloi1@westat.com>
>
> Thomas Rick <rthomas@WOOLWORTHS.COM.AU> describes a classic problem.
> He has to invoke a macro a number of times
>
> > %BMB1P(SYSTEM1,DAILY RUN DURATION);
>
> He has coded
>
> > %MACRO GRAPHIT;
> > %DO I=1 %TO &SYCNT %BY 1;
> > %BMB1P(&&SYSNAM&I,DAILY RUN DURATION);
> > %END;
> > %MEND;
> >
> > %GRAPHIT;
>
> to do the job, but
>
> > The macro executes perfectly for SYSTEM1, then executes for
> > SYSTEM5, and then executes repeatedly for SYSTEM4 until I cancel
> > the job. The data is correctly sorted by system.
>
> This is a classic description of a clash in names of macro variables. The
> macro BMB1P has a macro variable I that is not
> declared local. Hence, when called by GRAPHIT, it uses the looping
> variable I of GRAPHIT. On the first call things work fine and I is
> set to 4. Bumped by the loop to 5 and executed resetting I to 3. Now I is
> repeatedly set to 3 and bumped to 4. So the same
> invocation is repeated until stopped.
>
> The best habit is declare all macro variable local. Add
>
> %local I ;
>
> to BMB1P to solve the problem. A poor solution would be to change the
> name of the looping variable in GRAPHIT until you found one that worked.
>
> Now let's consider the problem - how should BMB1P be invoked multiple
> times? Thomas' solution:
>
> > I have done is to read the input data and generate the following
> > macro variables;
> >
> > SYSNAM1......SYSNAMn containing each system name (SYSTEM1 ...
> > SYSTEMn). SYCNT containing the number of systems in the input
> > data (which is equal to n).
>
> and then writing is managing macro is a good old solution to the problem.
> I find it annoying that a lot of extra variables are
> generated and not explicitly described in the interface for GRAPHIT. With
> version 6.07+ one can do better with using CALL EXECUTE.
>
> data _null_ ;
> infile ... ;
> input @... system $char.... ;
>
> call execute ( '%BMB1P(' || SYSTEM
> || ",DAILY RUN DURATION)" ) ;
> run ;
>
> This solution will not work if BMB1P uses execution of a step to create a
> macro variable, e.g. CALL SYMPUT or PROC SQL. Otherwise it is the
> simplest solution to the looping problem.
>
> Note that Thomas' solution works without restrictions on the code in the
> called macro.
>
> > %MACRO GRAPHIT;
> > DATA _NULL_;
> > FILE FT15F002 NOTITLES LINESIZE=72;
> > %DO I=1 %TO &SYCNT %BY 1;
> > PUT @3 '%BMB1P('
> > @10 "&&SYSNAM&I,DAILY RUN DURATION)";
> > %END;
> > RUN;
> > %MEND;
> >
> > %GRAPHIT;
> >
> > %INCLUDE FT15F002;
>
> Why wasn't there a conflict with I's here? GRAPHIT finished executing
> before the %INCLUDE was executed, hence BMB1P used a local I and caused no
> problems. A system independent solution would use a temporary catalog to
> store the code generated.
>
> filename code catalog "work.temp.bmb1ps.source" ;
>
> Now reference CODE instead of FT15F002 in the preceding code.
>
> Ian Whitlock
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