Getting filename from SYSIN-option in SAS

The code below makes it possible to extract the filename from the filename being executed through the SYSIN-option in SAS.

%macro GetProgramNameFromBatch(_PgmName=);
        %let PgmName = &_PgmName;
        %let PgmNameRev = %sysfunc(reverse(&PgmName));
        %let SlashPos = %index(&PgmNameRev, /);
        %if &SlashPos eq 0 %then
        %do;
                %let SlashPos = %index(&PgmNameRev, \);
        %end;
        %if &SlashPos ne 0 %then
        %do;
                %let PgmNameRev = %substr(&PgmNameRev, 1, %eval(&SlashPos-1));
                %let PgmName = %sysfunc(reverse(&PgmNameRev));
        %end;
        %else
        %do;
                %let PgmName = %sysfunc(reverse(&PgmNameRev));
        %end;

        &PgmName
%mend;

%let PgmName = %GetProgramNameFromBatch(_PgmName=/sas/Batchjobs/Test.sas);
%put Programname = &PgmName;

%let PgmName = %GetProgramNameFromBatch(_PgmName=c:\sas\Test_sysin.sas);
%put Programname = &PgmName;

%let PgmName = %GetProgramNameFromBatch(_PgmName=Test_sysin.sas);
%put Programname = &PgmName;