So here is a little demo of the timing issues around CALL EXECUTE and CALL SYMPUTX().
First let's define a little macro that references some macro variable that is NOT one of its parameters.
%macro mymac;
data _null_;
* Here is the code the macro generates ;
mvarvalue=symget('mymvar');
put mvarvalue=;
run;
%mend mymac;
Now let's try a little data step that sets values to the macro variable using CALL SYMPUTX() and calls the macro using CALL EXECUTE().
data _null_;
call symput('mymvar','First Value');
call execute('%mymac;');
call symput('mymvar','Second Value');
call execute('%mymac;');
run;
Notice how the code that the macro generates is echoed to the log with the + sign in front of it. Also notice how both runs of the macro used the second value of MYMVAR.
9 data _null_;
10 call symput('mymvar','First Value');
11 call execute('%mymac;');
12 call symput('mymvar','Second Value');
13 call execute('%mymac;');
14 run;
NOTE: DATA statement used (Total process time):
real time 0.25 seconds
cpu time 0.01 seconds
NOTE: CALL EXECUTE generated line.
1 + data _null_; * Here is the code the macro generates ; mvarvalue=symget('mymvar'); put
mvarvalue=; run;
mvarvalue=Second Value
NOTE: DATA statement used (Total process time):
real time 0.00 seconds
cpu time 0.00 seconds
1 +
;
2 + data _null_; * Here is the code the macro generates ; mvarvalue=symget('mymvar'); put
mvarvalue=; run;
mvarvalue=Second Value
NOTE: DATA statement used (Total process time):
real time 0.00 seconds
cpu time 0.01 seconds
2 +
;
15
Now if we use %NRSTR() to prevent the macro call from being expanded while the code it being pushed onto the stack to run.
data _null_;
call symput('mymvar','First Value');
call execute('%nrstr(%mymac);');
call symput('mymvar','Second Value');
call execute('%nrstr(%mymac);');
run;
Notice how now the lines with + in front just show the call to the macro. But the result is still just showing the second value assigned to MYMVAR.
16 data _null_;
17 call symput('mymvar','First Value');
18 call execute('%nrstr(%mymac);');
19 call symput('mymvar','Second Value');
20 call execute('%nrstr(%mymac);');
21 run;
NOTE: DATA statement used (Total process time):
real time 0.00 seconds
cpu time 0.00 seconds
NOTE: CALL EXECUTE generated line.
1 + %mymac;
mvarvalue=Second Value
NOTE: DATA statement used (Total process time):
real time 0.00 seconds
cpu time 0.00 seconds
2 + %mymac;
mvarvalue=Second Value
NOTE: DATA statement used (Total process time):
real time 0.00 seconds
cpu time 0.00 seconds
Now if we use %NRSTR() around %LET to generate a %LET statement.
data _null_;
call execute(cats('%nrstr(%let) mymvar=','First Value',';'));
call execute('%nrstr(%mymac);');
call execute(cats('%nrstr(%let) mymvar=','Second Value',';'));
call execute('%nrstr(%mymac);');
run;
We see that the macro variable MYMVAR is updated AFTER the first run of the macro.
22 data _null_;
23 call execute(cats('%nrstr(%let) mymvar=','First Value',';'));
24 call execute('%nrstr(%mymac);');
25 call execute(cats('%nrstr(%let) mymvar=','Second Value',';'));
26 call execute('%nrstr(%mymac);');
27 run;
NOTE: DATA statement used (Total process time):
real time 0.00 seconds
cpu time 0.00 seconds
NOTE: CALL EXECUTE generated line.
1 + %let mymvar=First Value;
2 + %mymac;
mvarvalue=First Value
NOTE: DATA statement used (Total process time):
real time 0.00 seconds
cpu time 0.00 seconds
3 + %let mymvar=Second Value;
4 + %mymac;
mvarvalue=Second Value
NOTE: DATA statement used (Total process time):
real time 0.00 seconds
cpu time 0.01 seconds
Finally we can just skip CALL EXECUTE() and use PUT to write the code and %INCLUDE to run it.
filename code temp;
data _null_;
file code;
put '%let mymvar=First Value;';
put '%mymac;';
put '%let mymvar=Second Value;';
put '%mymac;';
run;
%include code / source2;
Now we have the full power of the PUT statement to make generating the code easier. We can stop after the data step and examine the generated code and make sure our code generation logic is correct. We can generate code that is formatted the way we like so that the log is easier to read. etc. etc.
37 filename code temp;
38 data _null_;
39 file code;
40 put '%let mymvar=First Value;';
41 put '%mymac;';
42 put '%let mymvar=Second Value;';
43 put '%mymac;';
44 run;
NOTE: The file CODE is:
Filename=C:\Users\ABERNA~1\AppData\Local\Temp\1\SAS Temporary
Files\_TD20432_AMRL20L6F1E4992_\#LN00058,
RECFM=V,LRECL=32767,File Size (bytes)=0,
Last Modified=01Jul2019:09:52:45,
Create Time=01Jul2019:09:52:45
NOTE: 4 records were written to the file CODE.
The minimum record length was 7.
The maximum record length was 25.
NOTE: DATA statement used (Total process time):
real time 0.00 seconds
cpu time 0.00 seconds
45 %include code / source2;
NOTE: %INCLUDE (level 1) file CODE is file C:\Users\ABERNA~1\AppData\Local\Temp\1\SAS Temporary
Files\_TD20432_AMRL20L6F1E4992_\#LN00058.
46 +%let mymvar=First Value;
47 +%mymac;
mvarvalue=First Value
NOTE: DATA statement used (Total process time):
real time 0.00 seconds
cpu time 0.00 seconds
48 +%let mymvar=Second Value;
49 +%mymac;
mvarvalue=Second Value
NOTE: DATA statement used (Total process time):
real time 0.00 seconds
cpu time 0.00 seconds
NOTE: %INCLUDE (level 1) ending.
PS If you define your macro to take its inputs as parameters instead of referencing "magic" macro variables that are assumed to have been created in advance then one aspect of the timing problem is eliminated.
data _null_;
call execute('%nrstr(%mymac)(mymvar=First Value)');
call execute('%nrstr(%mymac)(mymvar=Second Value)');
run;
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