SAS macro functions outside of macro block or data step

Question

I'm having problems with getting the hang of using functions in SAS, the syntax is confusing.

I'm trying to get name without a date in the end. For example I have something like this: "MODEL_NAME_202101" and I want "MODEL_NAME".

I'm doing it like so.

%let model_ds = 
%sysfunc(
    substr(
        %scan(&models_list, 12), 
        0, 
        %length(%scan(&models_list, 12)) - 7
    )
);

%put &model_ds;

And only thing I get is a warring that tells me nothing about syntax errors I'm making.

WARNING: Argument 2 to function SUBSTR referenced by the %SYSFUNC or %QSYSFUNC macro function is out of range.

No idea how I'm supposed to nest function calls. Is every call required to have %sysfunc before call, or nesting functions inside already called function inside %sysfunc are syntax correct.

Would be nice if someone could reference me to explanation/documentation of this specific "feature",

Thanks

Answer 1

Rhythm is likely correct about the best solution for you - but the specific error:

WARNING: Argument 2 to function SUBSTR referenced by the %SYSFUNC or %QSYSFUNC macro function is out of range.

That's because of this:

substr(...,0,...)

That second argument is "what position to start from". SAS is 1-based, not 0-based (are you a python developer originally? This may be a bit challenging then!), so it needs to never be lower than 1.

substr(...,1,...)