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.
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.