In which criteria we have to use positional and keyword parameters in macro

[shivakrishna]

Hi All,

Could you please anyone explain in which situation we have to use which parameter like key and positional parameters.

Is there any particular situation for using those parameters.

Thanks

Shiva

[jakarman]

That is the macro designers job to decide.  To help, the parameter approach is easier with setting default values. SAS(R) 9.3 Macro Language: Reference (%macro)

[RW9]

I would use named parameters as much as possible.  They are easier to document, make the code easier to read.  For instance if you optional parameters you could have either:

%macro do_something (avar,avar2,,,,,,some_new_var,,,,);

Or

%macro do_something (variable_to_process=avar,

                                        variable_label=avar2,

                                        output_variable=some_new_var);

This is however an opinion, and there are some occasions where it doesn't help any to have named parameters, for instance where macros are embedded in other macros:

%macro big_loop (loop_start=,loop_end=,var=);

     %macro inner_loop (a,b);

          do loop over a to b;

     %mend inner_loop;

     %inner_loop(loop_start,loop_end;

%mend big_loop;    

As the user never sees the inner loop macro, then it really doesn't need documenting.  So, if another person has to use it, maybe veer towards named paramers.