C:\Steve\Dev\PerlMonks\P-2013-08-13@1518-Time-Days-Discount-Computation>doit1.pl
Possible unintended interpolation of @ymd2 in string at C:\Steve\Dev\PerlMonks\P-2013-08-13@1518-Time-Days-Discount-Computation\doit1.pl line 33.

Line 33:    my @ymd1 = split ',',$dates[4] //= $prev_mth_end;

Execution of C:\Steve\Dev\PerlMonks\P-2013-08-13@1518-Time-Days-Discount-Computation\doit1.pl aborted due to compilation errors.