I would like to check if a record meets the requirements of '8 digits long', '1st digit is a upcase letter', '2-8th digits are number (0-9)'.
I have used custom manipulator to create new variables:

first_char :=  substring(varname,1,1);
rest_num := substring(varname,2);
string_len := strlength(varname);

custom filter is connected after the custom manipulator:
/* filter out varname longer and shorter than 8 and first digit is not a letter and 2-8 digits contain numbers */
(string_length == 8) and (rest_num eq '0-9') and (first_char eq 'A-Z');

I was using isnumber to check rest_num but I might be using the function incorrectly so I did not get it to work. So, I thought I could use regular expression.

I inserted two records (12345678, A123456D) to test if the filter works. But, everything went to the fail port, even records that satisfy the requirements ex. A1234567. 

Records are in excel file and was read into pipeline pilot. I will appreciate any input!