This directory contains files of elisp that customize Emacs for certain terminal types. When Emacs starts, it checks the TERM environment variable to see what type of terminal the user is running on, checks for an elisp file named "term/${TERM}.el", and if one exists, loads it. If that doesn't yield a file that exists, the last hyphen and what follows it is stripped. If that doesn't yield a file that exists, the previous hyphen is stripped, and so on until all hyphens are gone. For example, if the terminal type is `aaa-48-foo', Emacs will try first `term/aaa-48-foo.el', then `term/aaa-48.el' and finally `term/aaa.el'. When writing terminal packages, there are some things it is good to keep in mind. First, about keycap names. Your terminal package can create any keycap cookies it likes, but there are good reasons to stick to the set recognized by the X-windows code whenever possible. The key symbols recognized by Emacs are listed in src/term.c; look for the string `keys' in that file. For one thing, it means that you'll have the same Emacs key bindings on in terminal mode as on an X console. If there are differences, you can bet they'll frustrate you after you've forgotten about them. For another, the X keysms provide a standard set of names that Emacs knows about. It tries to bind many of them to useful things at startup, before your .emacs is read (so you can override them). In some ways, the X keysym standard is a admittedly poor one; it's incomplete, and not well matched to the set of `virtual keys' that UNIX terminfo(3) provides. But, trust us, the alternatives were worse. This doesn't mean that if your terminal has a "Cokebottle" key you shouldn't define a [cokebottle] keycap. But if you must define cookies that aren't in that set, try to pattern them on the standard terminfo variable names for clarity; also, for a fighting chance that your binding may be useful to someone else someday. For example, if your terminal has a `find' key, observe that terminfo supports a key_find capability and call your cookie [key-find]. Here is a complete list, with corresponding X keysyms. ----------------------------------------------------------------------------- Variable name cap X Keysym Description -------------- --- ------------ ------------------------------------- key_down kd down Sent by terminal down arrow key key_up ku up Sent by terminal up arrow key key_left kl left Sent by terminal left arrow key key_right kr right Sent by terminal right arrow key key_home kh home Sent by home key. key_backspace kb Sent by backspace key key_dl kd deleteline Sent by delete line key. key_il kA insertline Sent by insert line. key_dc kD Sent by delete character key. key_ic kI insertchar (1) Sent by ins char/enter ins mode key. key_eic KM Sent by rmir or smir in insert mode. key_clear kC Sent by clear screen or erase key. key_eos kS Sent by clear-to-end-of-screen key. key_eol kE Sent by clear-to-end-of-line key. key_sf kF Sent by scroll-forward/down key key_sr kR Sent by scroll-backward/up key key_npage kN next (2) Sent by next-page key key_ppage kP prior (2) Sent by previous-page key key_stab kT Sent by set-tab key key_ctab kt Sent by clear-tab key key_catab ka Sent by clear-all-tabs key. key_enter @8 kp-enter Enter/send (unreliable) key_print %9 print print or copy key_ll kH Sent by home-down key key_a1 K1 kp-1 Upper left of keypad key_a3 K3 kp-3 Upper right of keypad key_b2 K2 kp-5 Center of keypad key_c1 K4 kp-7 Lower left of keypad key_c3 K5 kp-9 Lower right of keypad key_btab kB backtab Back tab key key_beg @1 begin beg(inning) key key_cancel @2 cancel cancel key key_close @3 close key key_command @4 execute (3) cmd (command) key key_copy @5 copy key key_create @6 create key key_end @7 end end key key_exit @9 exit key key_find @0 find key key_help %1 help key key_mark %2 mark key key_message %3 message key key_move %4 move key key_next %5 next (2) next object key key_open %6 open key key_options %7 menu (3) options key key_previous %8 previous (2) previous object key key_redo %0 redo redo key key_reference &1 ref(erence) key key_refresh &2 refresh key key_replace &3 replace key key_restart &4 reset (3) restart key key_resume &5 resume key key_save &6 save key key_sbeg &9 shifted beginning key key_select *6 select select key key_suspend &7 suspend key key_undo &8 undo undo key key_scancel &0 shifted cancel key key_scommand *1 shifted command key key_scopy *2 shifted copy key key_screate *3 shifted create key key_sdc *4 shifted delete char key key_sdl *5 shifted delete line key key_send *7 shifted end key key_seol *8 shifted clear line key key_sexit *9 shifted exit key key_sf kF shifted find key key_shelp #1 shifted help key key_shome #2 shifted home key key_sic #3 shifted input key key_sleft #4 shifted left arrow key key_smessage %a shifted message key key_smove %b shifted move key key_snext %c shifted next key key_soptions %d shifted options key key_sprevious %e shifted prev key key_sprint %f shifted print key key_sredo %g shifted redo key key_sreplace %h shifted replace key key_sright %i shifted right arrow key_sresume %j shifted resume key key_ssave !1 shifted save key key_suspend !2 shifted suspend key key_sundo !3 shifted undo key key_f0 k0 f0 (4) function key 0 key_f1 k1 f1 function key 1 key_f2 k2 f2 function key 2 key_f3 k3 f3 function key 3 key_f4 k4 f4 function key 4 key_f5 k5 f5 function key 5 key_f6 k6 f6 function key 6 key_f7 k7 f7 function key 7 key_f8 k8 f8 function key 8 key_f9 k9 f9 function key 9 key_f10 k; f10 (4) function key 10 key_f11 F1 f11 function key 11 : : : : key_f35 FP f35 function key 35 key_f36 FQ function key 36 : : : : key_f64 k1 function key 64 (1) The terminfo documentation says this may be the 'insert character' or `enter insert mode' key. Accordingly, key_ic is mapped to the `insertchar' keysym if there is also a key_dc key; otherwise it's mapped to `insert'. The presumption is that keyboards with `insert character' keys usually have `delete character' keys paired with them. (2) If there is no key_next key but there is a key_npage key, key_npage will be bound to the `next' keysym. If there is no key_previous key but there is a key_ppage key, key_ppage will be bound to the `previous' keysym. (3) Sorry, these are not exact but they're the best we can do. (4) The uses of the "k0" capability are inconsistent; sometimes it describes F10, whereas othertimes it describes F0 and "k;" describes F10. Emacs attempts to politely accommodate both systems by testing for "k;", and if it is present, assuming that "k0" denotes F0, otherwise F10. ----------------------------------------------------------------------------- The following X keysyms do *not* have terminfo equivalents. These are the cookies your terminal package will have to set up itself, if you want them: break system user kp-backtab kp-space kp-tab kp-f1 kp-f2 kp-f3 kp-f4 kp-multiply kp-add kp-separator kp-subtract kp-decimal kp-divide kp-0 kp-2 kp-4 kp-6 kp-8 kp-equal In general, you should not bind any of the standard keysym names to functions in a terminal package. There's code in loaddefs.el that does that; the less people make exceptions to that, the more consistent an interface Emacs will have across different keyboards. Those exceptions should go in your .emacs file. Finally, if you're using a USL UNIX or a Sun box or anything else with the USL version of curses(3) on it, bear in mind that the original curses(3) had (and still has) a very much smaller set of keycaps. In fact, the reliable ones were just the arrow keys and the first ten function keys. If you care about making your package portable to older Berkeley machines, don't count on the setup code to bind anything else. If your terminal's arrow key sequences are so funky that they conflict with normal Emacs key bindings, the package should set up a function called (enable-foo-arrow-keys), where `foo' becomes the terminal name, and leave it up to the user's .emacs file whether to call it. Before writing a terminal-support package, it's a good idea to read the existing ones and learn the common conventions.