IBP banding data system: emacs customizations

The tab key is bound to the 'ibp-tab function. It skips to the next field and supplies default content.

This binding is accomplished by this code:

(global-set-key "\C-i" 'ibp-tab)

The key's name is described here as Control-I, which is another way of describing the ASCII HT (horizontal tab) character.

The 'ibp-ditto function duplicates the current field using the last previous line that contains that field. The author's bindings have varied over time, but the important thing is to have a binding that is easy to reach (because this key is heavily used) and works the same way on multiple platforms.

The current binding uses Control plus the key that contains hyphen and underbar. As it happens, emacs running in no-window mode (option -nw) transmits this as Control-_, while in a separate window it transmits as Control--. So we'll bind both those combinations like this:

(global-set-key [?\C-_] 'ibp-ditto)
(global-set-key [?\C--] 'ibp-ditto)

The first argument to global-set-key in these cases uses emacs's vector notation.