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1 This directory contains files of elisp that customize Emacs for certain
2 terminal types.
4 When Emacs starts, it checks the TERM environment variable to see what type
5 of terminal the user is running on, checks for an elisp file named
6 "term/${TERM}.el", and if one exists, loads it. If that doesn't yield a file
7 that exists, the last hyphen and what follows it is stripped. If that doesn't
8 yield a file that exists, the previous hyphen is stripped, and so on until all
9 hyphens are gone. For example, if the terminal type is `aaa-48-foo', Emacs
10 will try first `term/aaa-48-foo.el', then `term/aaa-48.el' and finally
11 `term/aaa.el'.
13 When writing terminal packages, there are some things it is good to keep in
14 mind.
16 First, about keycap names. Your terminal package can create any keycap
17 cookies it likes, but there are good reasons to stick to the set recognized by
18 the X-windows code whenever possible. The key symbols recognized by Emacs
19 are listed in src/term.c; look for the string `keys' in that file.
21 For one thing, it means that you'll have the same Emacs key bindings on in
22 terminal mode as on an X console. If there are differences, you can bet
23 they'll frustrate you after you've forgotten about them.
25 For another, the X keysms provide a standard set of names that Emacs knows
26 about. It tries to bind many of them to useful things at startup, before your
27 .emacs is read (so you can override them). In some ways, the X keysym standard
28 is a admittedly poor one; it's incomplete, and not well matched to the set of
29 `virtual keys' that UNIX terminfo(3) provides. But, trust us, the alternatives
30 were worse.
32 This doesn't mean that if your terminal has a "Cokebottle" key you shouldn't
33 define a [cokebottle] keycap. But if you must define cookies that aren't in
34 that set, try to pattern them on the standard terminfo variable names for
35 clarity; also, for a fighting chance that your binding may be useful to someone
36 else someday.
38 For example, if your terminal has a `find' key, observe that terminfo
39 supports a key_find capability and call your cookie [find].
41 Here is a complete list, with corresponding X keysyms.
43 -----------------------------------------------------------------------------
44 Variable name cap X Keysym Description
45 -------------- --- ------------ -------------------------------------
46 key_down kd down Sent by terminal down arrow key
47 key_up ku up Sent by terminal up arrow key
48 key_left kl left Sent by terminal left arrow key
49 key_right kr right Sent by terminal right arrow key
50 key_home kh home Sent by home key.
51 key_backspace kb Sent by backspace key
52 key_dl kd deleteline Sent by delete line key.
53 key_il kA insertline Sent by insert line.
54 key_dc kD Sent by delete character key.
55 key_ic kI insertchar (1) Sent by ins char/enter ins mode key.
56 key_eic KM Sent by rmir or smir in insert mode.
57 key_clear kC Sent by clear screen or erase key.
58 key_eos kS Sent by clear-to-end-of-screen key.
59 key_eol kE Sent by clear-to-end-of-line key.
60 key_sf kF Sent by scroll-forward/down key
61 key_sr kR Sent by scroll-backward/up key
62 key_npage kN next (2) Sent by next-page key
63 key_ppage kP prior (2) Sent by previous-page key
64 key_stab kT Sent by set-tab key
65 key_ctab kt Sent by clear-tab key
66 key_catab ka Sent by clear-all-tabs key.
67 key_enter @8 kp-enter Enter/send (unreliable)
68 key_print %9 print print or copy
69 key_ll kH Sent by home-down key
70 key_a1 K1 kp-1 Upper left of keypad
71 key_a3 K3 kp-3 Upper right of keypad
72 key_b2 K2 kp-5 Center of keypad
73 key_c1 K4 kp-7 Lower left of keypad
74 key_c3 K5 kp-9 Lower right of keypad
75 key_btab kB backtab Back tab key
76 key_beg @1 begin beg(inning) key
77 key_cancel @2 cancel cancel key
78 key_close @3 close key
79 key_command @4 execute (3) cmd (command) key
80 key_copy @5 copy key
81 key_create @6 create key
82 key_end @7 end end key
83 key_exit @9 exit key
84 key_find @0 find key
85 key_help %1 help key
86 key_mark %2 mark key
87 key_message %3 message key
88 key_move %4 move key
89 key_next %5 next (2) next object key
90 key_open %6 open key
91 key_options %7 menu (3) options key
92 key_previous %8 previous (2) previous object key
93 key_redo %0 redo redo key
94 key_reference &1 ref(erence) key
95 key_refresh &2 refresh key
96 key_replace &3 replace key
97 key_restart &4 reset (3) restart key
98 key_resume &5 resume key
99 key_save &6 save key
100 key_sbeg &9 shifted beginning key
101 key_select *6 select select key
102 key_suspend &7 suspend key
103 key_undo &8 undo undo key
105 key_scancel &0 shifted cancel key
106 key_scommand *1 shifted command key
107 key_scopy *2 shifted copy key
108 key_screate *3 shifted create key
109 key_sdc *4 shifted delete char key
110 key_sdl *5 shifted delete line key
111 key_send *7 shifted end key
112 key_seol *8 shifted clear line key
113 key_sexit *9 shifted exit key
114 key_sf kF shifted find key
115 key_shelp #1 shifted help key
116 key_shome #2 shifted home key
117 key_sic #3 shifted input key
118 key_sleft #4 shifted left arrow key
119 key_smessage %a shifted message key
120 key_smove %b shifted move key
121 key_snext %c shifted next key
122 key_soptions %d shifted options key
123 key_sprevious %e shifted prev key
124 key_sprint %f shifted print key
125 key_sredo %g shifted redo key
126 key_sreplace %h shifted replace key
127 key_sright %i shifted right arrow
128 key_sresume %j shifted resume key
129 key_ssave !1 shifted save key
130 key_suspend !2 shifted suspend key
131 key_sundo !3 shifted undo key
133 key_f0 k0 f0 (4) function key 0
134 key_f1 k1 f1 function key 1
135 key_f2 k2 f2 function key 2
136 key_f3 k3 f3 function key 3
137 key_f4 k4 f4 function key 4
138 key_f5 k5 f5 function key 5
139 key_f6 k6 f6 function key 6
140 key_f7 k7 f7 function key 7
141 key_f8 k8 f8 function key 8
142 key_f9 k9 f9 function key 9
143 key_f10 k; f10 (4) function key 10
144 key_f11 F1 f11 function key 11
145 : : : :
146 key_f35 FP f35 function key 35
147 key_f36 FQ function key 36
148 : : : :
149 key_f64 k1 function key 64
151 (1) The terminfo documentation says this may be the 'insert character' or
152 `enter insert mode' key. Accordingly, key_ic is mapped to the `insertchar'
153 keysym if there is also a key_dc key; otherwise it's mapped to `insert'.
154 The presumption is that keyboards with `insert character' keys usually
155 have `delete character' keys paired with them.
157 (2) If there is no key_next key but there is a key_npage key, key_npage
158 will be bound to the `next' keysym. If there is no key_previous key but
159 there is a key_ppage key, key_ppage will be bound to the `previous' keysym.
161 (3) Sorry, these are not exact but they're the best we can do.
163 (4) The uses of the "k0" capability are inconsistent; sometimes it
164 describes F10, whereas othertimes it describes F0 and "k;" describes F10.
165 Emacs attempts to politely accommodate both systems by testing for
166 "k;", and if it is present, assuming that "k0" denotes F0, otherwise F10.
167 -----------------------------------------------------------------------------
169 The following X keysyms do *not* have terminfo equivalents. These are
170 the cookies your terminal package will have to set up itself, if you want them:
172 break
173 system
174 user
175 kp-backtab
176 kp-space
177 kp-tab
178 kp-f1
179 kp-f2
180 kp-f3
181 kp-f4
182 kp-multiply
183 kp-add
184 kp-separator
185 kp-subtract
186 kp-decimal
187 kp-divide
188 kp-0
189 kp-2
190 kp-4
191 kp-6
192 kp-8
193 kp-equal
195 In general, you should not bind any of the standard keysym names to
196 functions in a terminal package. There's code in loaddefs.el that does that;
197 the less people make exceptions to that, the more consistent an interface Emacs
198 will have across different keyboards. Those exceptions should go in your
199 .emacs file.
201 Finally, if you're using a USL UNIX or a Sun box or anything else with the
202 USL version of curses(3) on it, bear in mind that the original curses(3) had
203 (and still has) a very much smaller set of keycaps. In fact, the reliable
204 ones were just the arrow keys and the first ten function keys. If you care
205 about making your package portable to older Berkeley machines, don't count on
206 the setup code to bind anything else.
208 If your terminal's arrow key sequences are so funky that they conflict with
209 normal Emacs key bindings, the package should set up a function called
210 (enable-foo-arrow-keys), where `foo' becomes the terminal name, and leave
211 it up to the user's .emacs file whether to call it.
213 Before writing a terminal-support package, it's a good idea to read the
214 existing ones and learn the common conventions.