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20 Miscellaneous

20.1 Abort Character

The abort character (Ctrl-G by default) is special and should not be rebound. On the IBMPC, the keyboard interrupt 0x09 is hooked and a quit condition is signaled when it is pressed. For this reason, it should not be used in any keybindings. A similar statement holds for the other systems.

This character may be changed using the function set_abort_char Using this function affects all keymaps. For example, putting the line

      set_abort_char (30);

in your jed.rc file will change the abort character from its current value to 30 which is Ctrl-^.

20.2 Input Translation

By using the function map_input the user is able to remap characters input from the terminal before jed’s keymap routines have a chance to act upon them. This is useful when it is difficult to get jed to see certain characters. For example, consider the Ctrl-S character. This character is especially notorious because many systems use it and Ctrl-Q for flow control. Nevertheless Emacs uses Ctrl-S for searching. Short of rebinding all keys which involve a Ctrl-S how does one work with functions that are bound to key sequences using Ctrl-S? This is where map_input comes into play. The map_input function requires two integer arguments which define how a given ascii character is to be mapped. Suppose that you wish to substitute Ctrl-\ for Ctrl-S everywhere. The line

      map_input (28, 19);

will do the trick. Here 28 is the ascii character of Ctrl-\ and 19 is the ascii character for the Ctrl-S.

As another example, consider the case where the backspace key sends out a Ctrl-H instead of the DEL character (Ctrl-?).

      map_input (8, 127);

will map the Ctrl-H (ascii 8) to the delete character (ascii 127).

20.3 Display Sizes

On VMS and unix systems, the screen size may be changed to either 80 or 132 columns by using the functions w80 and w132 respectively. Simply enter the appropriate function name at the M-x prompt in the minibuffer. The default binding for access to the minibuffer is Esc X. Most window systems, e.g., DECWindows, allow the window size to be changed. When this is done, jed should automatically adapt to the new size.

On the PC, at this time the screen size cannot be changed while jed is running. Instead it is necessary to exit jed first then set the display size and rerun jed.


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