Basically a simple_type that auto-increments a field that is uneditable, for every new item that is created in that database, or the folder, according to a format.
Example: Quotations to be formated according to AB-Q-######-.revisionfield
or Some Ticket each ticket has its each own identifiable number in series formatted as Tic######
Syntax: serial|prepend-text|default start number|increment|append field <optional|
Syntax 1: field name:"sequenceno" description:"Ticket Number" simple_type="serial_folder|'AB-Q-'|1000|1"
for unique number in table, and not just this folder
Syntax 2: field name:"sequenceno" description:"Ticket Number" simple_type="serial|'AB-Q'|1000|2|otherfieldname"
This can be useful in many uses and types of documents, further id doesn't cut it because it appends the record number with the server number, so each consecutive record is 100 more than previous, and it doesn't allow you to set a fixed starting point, unless manually done.
sgsml-parser and simple_types could gain from this I think. So could the modules.