iband7: IBP banding data entry system

Despite specific instructions to the contrary, some banders insist on using some form of dittoing for single-column fields. Sometimes it is the standard IBP ditto character (<). More often it is that character backwards (>): this character is particularly evil because it can be very difficult to tell it from the digit 7. Other banders use wavy lines or the common English ditto (").

Without some support from the software, such a mark can bog down data entry significantly. Most of the time, the data entry operator's eye can stay on the line they're entering—and that's important because it can be easy to lose one's place on a crowded banding sheet. Dittoing of entire fields, which is recommended by IBP, is handled by features described in Section 8, “The emacs extensions”.

However, single-column ditto refers to a previous field that may be several lines away from the reference. The data entry operator's eye would have to leave the current line, find the referenced value, type it, and then try to get back to their previous location. This really messes up the operator's rhythm and can make entering such a line several times slower than a normal line.

Consequently, the data compilers support a special convention that allows the data entry operator to enter a single character and keep rolling, and the compiler will figure out what value is being dittoed.

The character double-quote (") will be interpreted as a single-column ditto of the value of that column in the previous line. This convention is allowed in all fields starting with the age group, through and including all the micro-aging fields.