7.1 Minor Display Modes

A minor display mode is a mode useful when using a specific type of buffer. This mode might not be useful for any other kind of data or mode, or may just be more useful that a files or buffers based mode when working with a specialized mode.

Examples that already exist for speedbar include RMAIL, Info, and gdb. These modes display information specific to the major mode shown in the attached frame.

To enable a minor display mode in your favorite Major mode, follow these steps. The string ‘name’ is the name of the major mode being augmented with speedbar.

  1. Create the keymap variable name-speedbar-mode-map.
  2. Create a function, named whatever you like, which assigns values into your keymap. Use this command to create the keymap before assigning bindings:
        (setq name-speedbar-mode-map (speedbar-make-specialized-keymap))

    This function creates a special keymap for use in speedbar.

  3. Call your install function, like this:
    (with-eval-after-load 'speedbar
  4. Create an easymenu compatible vector named name-speedbar-menu-items. This will be spliced into speedbar’s control menu.
  5. Create a function called name-speedbar-buttons. This function should take one variable, which is the buffer for which it will create buttons. At this time (current-buffer) will point to the uncleared speedbar buffer.

When writing name-speedbar-buttons, the first thing you will want to do is execute a check to see if you need to re-create your display. If it needs to be cleared, you need to erase the speedbar buffer yourself, and start drawing buttons. See Creating a display.