1Copyright (C) 1993, 2001-2021 Free Software Foundation, Inc. 2See the end of the file for license conditions. 3 4 5 This directory contains files of elisp that customize Emacs for certain 6terminal types. 7 8 When Emacs opens a new terminal, it checks the TERM environment variable 9to see what type of terminal the user is running on. (If there is an entry 10for TERM in the 'term-file-aliases' variable, Emacs uses the associated value 11in place of TERM in the following.) Emacs searches for an elisp file named 12"term/${TERM}.el", and if one exists, loads it. If Emacs finds no 13suitable file, then it strips the last hyphen and what follows it from TERM, 14and tries again. If that still doesn't yield a file, then the previous hyphen 15is stripped, and so on until all hyphens are gone. For example, if the 16terminal type is 'aaa-48-foo', Emacs will try first 'term/aaa-48-foo.el', then 17'term/aaa-48.el' and finally 'term/aaa.el'. Emacs stops searching at the 18first file found, and will not load more than one file for any terminal. Note 19that it is not an error if Emacs is unable to find a terminal initialization 20file; in that case, it will simply proceed with the next step without loading 21any files. 22 23 Once the file has been loaded (or the search failed), Emacs tries to call a 24function named 'terminal-init-TERMINALNAME' (eg 'terminal-init-aaa-48' for the 25'aaa-48' terminal) in order to initialize the terminal. Once again, if the 26function is not found, Emacs strips the last component of the name and tries 27again using the shorter name. This search is independent of the previous file 28search, so that you can have terminal initialization functions for a family of 29terminals collected in a single file named after the family name, and users 30may put terminal initialization functions directly in their .emacs files. 31 32 Note that an individual terminal file is loaded only once in an Emacs 33session; if the same terminal type is opened again, Emacs will simply call the 34initialization function without reloading the file. Therefore, all the actual 35initialization actions should be collected in terminal-init-* functions; the 36file should not contain any top-level form that is not a function or variable 37declaration. Simply loading the file should not have any side effect. 38 39 Similarly, the terminal initialization function is called only once on any 40given terminal, when the first frame is created on it. The function is not 41called for subsequent frames on the same terminal. Therefore, terminal-init-* 42functions should only modify terminal-local variables (such as 43'local-function-key-map') and terminal parameters. For example, it is not 44correct to modify frame parameters, since the modifications will only be 45applied for the first frame opened on the terminal. 46 47 48 When writing terminal packages, there are some things it is good to keep in 49mind. 50 51 First, about keycap names. Your terminal package can create any keycap 52cookies it likes, but there are good reasons to stick to the set recognized by 53the X-windows code whenever possible. The key symbols recognized by Emacs 54are listed in src/term.c; look for the string 'keys' in that file. 55 56 For one thing, it means that you'll have the same Emacs key bindings on in 57terminal mode as on an X console. If there are differences, you can bet 58they'll frustrate you after you've forgotten about them. 59 60 For another, the X keysyms provide a standard set of names that Emacs knows 61about. It tries to bind many of them to useful things at startup, before your 62.emacs is read (so you can override them). In some ways, the X keysym standard 63is an admittedly poor one; it's incomplete, and not well matched to the set of 64'virtual keys' that UNIX terminfo(3) provides. But, trust us, the alternatives 65were worse. 66 67 This doesn't mean that if your terminal has a "Cokebottle" key you shouldn't 68define a [cokebottle] keycap. But if you must define cookies that aren't in 69that set, try to pattern them on the standard terminfo variable names for 70clarity; also, for a fighting chance that your binding may be useful to someone 71else someday. 72 73 For example, if your terminal has a 'find' key, observe that terminfo 74supports a key_find capability and call your cookie [find]. 75 76Here is a complete list, with corresponding X keysyms. 77 78----------------------------------------------------------------------------- 79Variable name cap X Keysym Description 80-------------- --- ------------ ------------------------------------- 81key_down kd down Sent by terminal down arrow key 82key_up ku up Sent by terminal up arrow key 83key_left kl left Sent by terminal left arrow key 84key_right kr right Sent by terminal right arrow key 85key_home kh home Sent by home key. 86key_backspace kb Sent by backspace key 87key_dl kd deleteline Sent by delete line key. 88key_il kA insertline Sent by insert line. 89key_dc kD Sent by delete character key. 90key_ic kI insertchar (1) Sent by ins char/enter ins mode key. 91key_eic KM Sent by rmir or smir in insert mode. 92key_clear kC Sent by clear screen or erase key. 93key_eos kS Sent by clear-to-end-of-screen key. 94key_eol kE Sent by clear-to-end-of-line key. 95key_sf kF Sent by scroll-forward/down key 96key_sr kR Sent by scroll-backward/up key 97key_npage kN next (2) Sent by next-page key 98key_ppage kP prior (2) Sent by previous-page key 99key_stab kT Sent by set-tab key 100key_ctab kt Sent by clear-tab key 101key_catab ka Sent by clear-all-tabs key. 102key_enter @8 kp-enter Enter/send (unreliable) 103key_print %9 print print or copy 104key_ll kH Sent by home-down key 105key_a1 K1 kp-1 Upper left of keypad 106key_a3 K3 kp-3 Upper right of keypad 107key_b2 K2 kp-5 Center of keypad 108key_c1 K4 kp-7 Lower left of keypad 109key_c3 K5 kp-9 Lower right of keypad 110key_btab kB backtab Back tab key 111key_beg @1 begin beg(inning) key 112key_cancel @2 cancel cancel key 113key_close @3 close key 114key_command @4 execute (3) cmd (command) key 115key_copy @5 copy key 116key_create @6 create key 117key_end @7 end end key 118key_exit @9 exit key 119key_find @0 find key 120key_help %1 help key 121key_mark %2 mark key 122key_message %3 message key 123key_move %4 move key 124key_next %5 next (2) next object key 125key_open %6 open key 126key_options %7 menu (3) options key 127key_previous %8 previous (2) previous object key 128key_redo %0 redo redo key 129key_reference &1 ref(erence) key 130key_refresh &2 refresh key 131key_replace &3 replace key 132key_restart &4 reset (3) restart key 133key_resume &5 resume key 134key_save &6 save key 135key_sbeg &9 shifted beginning key 136key_select *6 select select key 137key_suspend &7 suspend key 138key_undo &8 undo undo key 139 140key_scancel &0 shifted cancel key 141key_scommand *1 shifted command key 142key_scopy *2 shifted copy key 143key_screate *3 shifted create key 144key_sdc *4 shifted delete char key 145key_sdl *5 shifted delete line key 146key_send *7 shifted end key 147key_seol *8 shifted clear line key 148key_sexit *9 shifted exit key 149key_sf kF shifted find key 150key_shelp #1 shifted help key 151key_shome #2 shifted home key 152key_sic #3 shifted input key 153key_sleft #4 shifted left arrow key 154key_smessage %a shifted message key 155key_smove %b shifted move key 156key_snext %c shifted next key 157key_soptions %d shifted options key 158key_sprevious %e shifted prev key 159key_sprint %f shifted print key 160key_sredo %g shifted redo key 161key_sreplace %h shifted replace key 162key_sright %i shifted right arrow 163key_sresume %j shifted resume key 164key_ssave !1 shifted save key 165key_suspend !2 shifted suspend key 166key_sundo !3 shifted undo key 167 168key_f0 k0 f0 (4) function key 0 169key_f1 k1 f1 function key 1 170key_f2 k2 f2 function key 2 171key_f3 k3 f3 function key 3 172key_f4 k4 f4 function key 4 173key_f5 k5 f5 function key 5 174key_f6 k6 f6 function key 6 175key_f7 k7 f7 function key 7 176key_f8 k8 f8 function key 8 177key_f9 k9 f9 function key 9 178key_f10 k; f10 (4) function key 10 179key_f11 F1 f11 function key 11 180 : : : : 181key_f35 FP f35 function key 35 182key_f36 FQ function key 36 183 : : : : 184key_f64 k1 function key 64 185 186(1) The terminfo documentation says this may be the 'insert character' or 187 'enter insert mode' key. Accordingly, key_ic is mapped to the 'insertchar' 188 keysym if there is also a key_dc key; otherwise it's mapped to 'insert'. 189 The presumption is that keyboards with 'insert character' keys usually 190 have 'delete character' keys paired with them. 191 192(2) If there is no key_next key but there is a key_npage key, key_npage 193 will be bound to the 'next' keysym. If there is no key_previous key but 194 there is a key_ppage key, key_ppage will be bound to the 'previous' keysym. 195 196(3) Sorry, these are not exact but they're the best we can do. 197 198(4) The uses of the "k0" capability are inconsistent; sometimes it 199 describes F10, whereas othertimes it describes F0 and "k;" describes F10. 200 Emacs attempts to politely accommodate both systems by testing for 201 "k;", and if it is present, assuming that "k0" denotes F0, otherwise F10. 202----------------------------------------------------------------------------- 203 204 The following X keysyms do *not* have terminfo equivalents. These are 205the cookies your terminal package will have to set up itself, if you want them: 206 207 break 208 system 209 user 210 kp-backtab 211 kp-space 212 kp-tab 213 kp-f1 214 kp-f2 215 kp-f3 216 kp-f4 217 kp-multiply 218 kp-add 219 kp-separator 220 kp-subtract 221 kp-decimal 222 kp-divide 223 kp-0 224 kp-2 225 kp-4 226 kp-6 227 kp-8 228 kp-equal 229 230 In general, you should not bind any of the standard keysym names to 231functions in a terminal package. There's code in loaddefs.el that does that; 232the less people make exceptions to that, the more consistent an interface Emacs 233will have across different keyboards. Those exceptions should go in your 234.emacs file. 235 236 Finally, if you're using a USL UNIX or a Sun box or anything else with the 237USL version of curses(3) on it, bear in mind that the original curses(3) had 238(and still has) a very much smaller set of keycaps. In fact, the reliable 239ones were just the arrow keys and the first ten function keys. If you care 240about making your package portable to older Berkeley machines, don't count on 241the setup code to bind anything else. 242 243 If your terminal's arrow key sequences are so funky that they conflict with 244normal Emacs key bindings, the package should set up a function called 245(enable-foo-arrow-keys), where 'foo' becomes the terminal name, and leave 246it up to the user's .emacs file whether to call it. 247 248 Before writing a terminal-support package, it's a good idea to read the 249existing ones and learn the common conventions. 250 251 252This file is part of GNU Emacs. 253 254GNU Emacs is free software: you can redistribute it and/or modify 255it under the terms of the GNU General Public License as published by 256the Free Software Foundation, either version 3 of the License, or 257(at your option) any later version. 258 259GNU Emacs is distributed in the hope that it will be useful, 260but WITHOUT ANY WARRANTY; without even the implied warranty of 261MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 262GNU General Public License for more details. 263 264You should have received a copy of the GNU General Public License 265along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>. 266