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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'. Each terminal specific file should contain a function
12 named terminal-init-TERMINALNAME (eg terminal-init-aaa-48 for
13 term/aaa-48.el) that Emacs will call in order to initialize the
14 terminal. The terminal files should not contain any top level forms
15 that are executed when the file is loaded, all the initialization
16 actions are performed by the terminal-init-TERMINALNAME functions.
18 When writing terminal packages, there are some things it is good to keep in
19 mind.
21 First, about keycap names. Your terminal package can create any keycap
22 cookies it likes, but there are good reasons to stick to the set recognized by
23 the X-windows code whenever possible. The key symbols recognized by Emacs
24 are listed in src/term.c; look for the string `keys' in that file.
26 For one thing, it means that you'll have the same Emacs key bindings on in
27 terminal mode as on an X console. If there are differences, you can bet
28 they'll frustrate you after you've forgotten about them.
30 For another, the X keysms provide a standard set of names that Emacs knows
31 about. It tries to bind many of them to useful things at startup, before your
32 .emacs is read (so you can override them). In some ways, the X keysym standard
33 is a admittedly poor one; it's incomplete, and not well matched to the set of
34 `virtual keys' that UNIX terminfo(3) provides. But, trust us, the alternatives
35 were worse.
37 This doesn't mean that if your terminal has a "Cokebottle" key you shouldn't
38 define a [cokebottle] keycap. But if you must define cookies that aren't in
39 that set, try to pattern them on the standard terminfo variable names for
40 clarity; also, for a fighting chance that your binding may be useful to someone
41 else someday.
43 For example, if your terminal has a `find' key, observe that terminfo
44 supports a key_find capability and call your cookie [find].
46 Here is a complete list, with corresponding X keysyms.
48 -----------------------------------------------------------------------------
49 Variable name cap X Keysym Description
50 -------------- --- ------------ -------------------------------------
51 key_down kd down Sent by terminal down arrow key
52 key_up ku up Sent by terminal up arrow key
53 key_left kl left Sent by terminal left arrow key
54 key_right kr right Sent by terminal right arrow key
55 key_home kh home Sent by home key.
56 key_backspace kb Sent by backspace key
57 key_dl kd deleteline Sent by delete line key.
58 key_il kA insertline Sent by insert line.
59 key_dc kD Sent by delete character key.
60 key_ic kI insertchar (1) Sent by ins char/enter ins mode key.
61 key_eic KM Sent by rmir or smir in insert mode.
62 key_clear kC Sent by clear screen or erase key.
63 key_eos kS Sent by clear-to-end-of-screen key.
64 key_eol kE Sent by clear-to-end-of-line key.
65 key_sf kF Sent by scroll-forward/down key
66 key_sr kR Sent by scroll-backward/up key
67 key_npage kN next (2) Sent by next-page key
68 key_ppage kP prior (2) Sent by previous-page key
69 key_stab kT Sent by set-tab key
70 key_ctab kt Sent by clear-tab key
71 key_catab ka Sent by clear-all-tabs key.
72 key_enter @8 kp-enter Enter/send (unreliable)
73 key_print %9 print print or copy
74 key_ll kH Sent by home-down key
75 key_a1 K1 kp-1 Upper left of keypad
76 key_a3 K3 kp-3 Upper right of keypad
77 key_b2 K2 kp-5 Center of keypad
78 key_c1 K4 kp-7 Lower left of keypad
79 key_c3 K5 kp-9 Lower right of keypad
80 key_btab kB backtab Back tab key
81 key_beg @1 begin beg(inning) key
82 key_cancel @2 cancel cancel key
83 key_close @3 close key
84 key_command @4 execute (3) cmd (command) key
85 key_copy @5 copy key
86 key_create @6 create key
87 key_end @7 end end key
88 key_exit @9 exit key
89 key_find @0 find key
90 key_help %1 help key
91 key_mark %2 mark key
92 key_message %3 message key
93 key_move %4 move key
94 key_next %5 next (2) next object key
95 key_open %6 open key
96 key_options %7 menu (3) options key
97 key_previous %8 previous (2) previous object key
98 key_redo %0 redo redo key
99 key_reference &1 ref(erence) key
100 key_refresh &2 refresh key
101 key_replace &3 replace key
102 key_restart &4 reset (3) restart key
103 key_resume &5 resume key
104 key_save &6 save key
105 key_sbeg &9 shifted beginning key
106 key_select *6 select select key
107 key_suspend &7 suspend key
108 key_undo &8 undo undo key
110 key_scancel &0 shifted cancel key
111 key_scommand *1 shifted command key
112 key_scopy *2 shifted copy key
113 key_screate *3 shifted create key
114 key_sdc *4 shifted delete char key
115 key_sdl *5 shifted delete line key
116 key_send *7 shifted end key
117 key_seol *8 shifted clear line key
118 key_sexit *9 shifted exit key
119 key_sf kF shifted find key
120 key_shelp #1 shifted help key
121 key_shome #2 shifted home key
122 key_sic #3 shifted input key
123 key_sleft #4 shifted left arrow key
124 key_smessage %a shifted message key
125 key_smove %b shifted move key
126 key_snext %c shifted next key
127 key_soptions %d shifted options key
128 key_sprevious %e shifted prev key
129 key_sprint %f shifted print key
130 key_sredo %g shifted redo key
131 key_sreplace %h shifted replace key
132 key_sright %i shifted right arrow
133 key_sresume %j shifted resume key
134 key_ssave !1 shifted save key
135 key_suspend !2 shifted suspend key
136 key_sundo !3 shifted undo key
138 key_f0 k0 f0 (4) function key 0
139 key_f1 k1 f1 function key 1
140 key_f2 k2 f2 function key 2
141 key_f3 k3 f3 function key 3
142 key_f4 k4 f4 function key 4
143 key_f5 k5 f5 function key 5
144 key_f6 k6 f6 function key 6
145 key_f7 k7 f7 function key 7
146 key_f8 k8 f8 function key 8
147 key_f9 k9 f9 function key 9
148 key_f10 k; f10 (4) function key 10
149 key_f11 F1 f11 function key 11
150 : : : :
151 key_f35 FP f35 function key 35
152 key_f36 FQ function key 36
153 : : : :
154 key_f64 k1 function key 64
156 (1) The terminfo documentation says this may be the 'insert character' or
157 `enter insert mode' key. Accordingly, key_ic is mapped to the `insertchar'
158 keysym if there is also a key_dc key; otherwise it's mapped to `insert'.
159 The presumption is that keyboards with `insert character' keys usually
160 have `delete character' keys paired with them.
162 (2) If there is no key_next key but there is a key_npage key, key_npage
163 will be bound to the `next' keysym. If there is no key_previous key but
164 there is a key_ppage key, key_ppage will be bound to the `previous' keysym.
166 (3) Sorry, these are not exact but they're the best we can do.
168 (4) The uses of the "k0" capability are inconsistent; sometimes it
169 describes F10, whereas othertimes it describes F0 and "k;" describes F10.
170 Emacs attempts to politely accommodate both systems by testing for
171 "k;", and if it is present, assuming that "k0" denotes F0, otherwise F10.
172 -----------------------------------------------------------------------------
174 The following X keysyms do *not* have terminfo equivalents. These are
175 the cookies your terminal package will have to set up itself, if you want them:
177 break
178 system
179 user
180 kp-backtab
181 kp-space
182 kp-tab
183 kp-f1
184 kp-f2
185 kp-f3
186 kp-f4
187 kp-multiply
188 kp-add
189 kp-separator
190 kp-subtract
191 kp-decimal
192 kp-divide
193 kp-0
194 kp-2
195 kp-4
196 kp-6
197 kp-8
198 kp-equal
200 In general, you should not bind any of the standard keysym names to
201 functions in a terminal package. There's code in loaddefs.el that does that;
202 the less people make exceptions to that, the more consistent an interface Emacs
203 will have across different keyboards. Those exceptions should go in your
204 .emacs file.
206 Finally, if you're using a USL UNIX or a Sun box or anything else with the
207 USL version of curses(3) on it, bear in mind that the original curses(3) had
208 (and still has) a very much smaller set of keycaps. In fact, the reliable
209 ones were just the arrow keys and the first ten function keys. If you care
210 about making your package portable to older Berkeley machines, don't count on
211 the setup code to bind anything else.
213 If your terminal's arrow key sequences are so funky that they conflict with
214 normal Emacs key bindings, the package should set up a function called
215 (enable-foo-arrow-keys), where `foo' becomes the terminal name, and leave
216 it up to the user's .emacs file whether to call it.
218 Before writing a terminal-support package, it's a good idea to read the
219 existing ones and learn the common conventions.