BASE36 - Add 1 to an Alpha-Numeric String in RPGLE

This is a service program that adds 1 to an alpha-numeric string. The string can be any (sensible) length but is currently set at a arbitrary max of 50 characters.

The code was originally developed to help out when a numeric key (kept in a character field) was about to hit the maximum, and the company did not want to re-structure their database. I had developed a solution back in RPG III days so converting it to RPGIV was a trivial task. (See midrange.com for the the thread the the other suggested solutions.)

Another potential use might be incrementing a unique alpha numeric part number.

The code is quite short and can be easily modified to change the maximum length.

It is currently set to use a BASE36 character set (A-Z and 0-9) and the raw EBCDIC code sorting sequence, where numbers are higher than characters. Changing either the character set of the sorting sequence simply requires changing two constants.

I've been experimenting with free Visual Studio Code and the Code for IBM i extension to VS Code, so using that I tidied up the code, made it into a service program, made it more flexible and wrote some testing code. Lots of fun and a good learning experience using the new, totally free, D-specs...

Note: This is not a BASE36 math package. I covers just the case of adding 1 to a string.

SRV-BASE36

This is the service program. It contains the BASE36ADD procedure. You call it with a value and it returns the value + 1. A typical call might be:

valVar = BASE36ADD(ValVar);

where ValVar is defined as varChar.

BASE36_P

This is the prototype for the BASE36ADD procedure.

BTBR

A batch program that exercises BASE36ADD. You call it with a starting and ending value and it writes the results to file BTB. A typical call might be like this:

CALL PGM(BTBR) PARM('988' '992')

This program drops (deletes), creates and writes to the file using SQL. I wanted to try this to avoid creating DDS for the file.

BTIR/BTID

A program to explore BASE36ADD interactively. You enter a starting value and each successive enter adds to a rolling display of values. Like this: Or this, with a longer value: