* Re: How to make <shift> work with <control> in xterm?
2006-10-14 5:01 How to make <shift> work with <control> in xterm? id.brep
@ 2006-10-14 6:00 ` Pascal Bourguignon
2006-10-14 8:43 ` id.brep
2006-10-14 12:05 ` dickey
2006-10-14 7:06 ` Harald Hanche-Olsen
2006-10-14 18:40 ` Ilya Zakharevich
2 siblings, 2 replies; 6+ messages in thread
From: Pascal Bourguignon @ 2006-10-14 6:00 UTC (permalink / raw)
id.brep@gmail.com writes:
> In the emacs manual, it's said:
>
> On ASCII terminals, there are only 32 possible control characters.
> These are the control variants of letters and `@[]\^_'. In addition,
> the shift key is meaningless with control characters: `C-a' and `C-A'
> are the same character, and Emacs cannot distinguish them.
>
> I use xterm, I think it's graphical terminal, is it possibleto make
> <shit>
> work with <control> in xterm?
Not AFAIK.
The question is that there is no line protocol to encode shit+control+key.
There is the ASCII code, with 33 control codes and 95 character codes.
Unshifted, we get characters between 32 and 47, and between 96 and 127.
The shift key is used to get the characters between 48 and 95.
The control key is used to get the control codes between 0 and 31.
So we only need 32 keys in addition to shift and control to generate
all the ASCII codes.
0 NUL 1 SOH 2 STX 3 ETX 4 EOT 5 ENQ 6 ACK 7 BEL
8 BS 9 TAB 10 LF 11 VT 12 FF 13 CR 14 SO 15 SI
16 DLE 17 DC1 18 DC2 19 DC3 20 DC4 21 NAK 22 SYN 23 ETB
24 CAN 25 EM 26 SUB 27 ESC 28 FS 29 GS 30 RS 31 US
32 SP 33 ! 34 " 35 # 36 $ 37 % 38 & 39 '
40 ( 41 ) 42 * 43 + 44 , 45 - 46 . 47 /
48 0 49 1 50 2 51 3 52 4 53 5 54 6 55 7
56 8 57 9 58 : 59 ; 60 < 61 = 62 > 63 ?
64 @ 65 A 66 B 67 C 68 D 69 E 70 F 71 G
72 H 73 I 74 J 75 K 76 L 77 M 78 N 79 O
80 P 81 Q 82 R 83 S 84 T 85 U 86 V 87 W
88 X 89 Y 90 Z 91 [ 92 \ 93 ] 94 ^ 95 _
96 ` 97 a 98 b 99 c 100 d 101 e 102 f 103 g
104 h 105 i 106 j 107 k 108 l 109 m 110 n 111 o
112 p 113 q 114 r 115 s 116 t 117 u 118 v 119 w
120 x 121 y 122 z 123 { 124 | 125 } 126 ~ 127 DEL
For Meta, we have the choice to use the old protocol, prefixing the
key with escape (ESC, code 27), or the new one, setting the high bit
on the 7-bit ASCII code. But this doesn't work well with iso-8859-1
keyboards, so we still often map Meta to ESC...
Apart from Meta sent as ESC, there's no protocol to encode the other
modifiers. We just send normal ASCII codes. On the other side, emacs
takes the ASCII codes and guess that some modifier keys were pressed
along with some character key. But of course, since there are not 64
control code, it can only man C-x, not C-S-x (C-X).
What could be done, is to define a protocol to encode and transmit all
the X keysyms thru a serial line, and patch xterm to use it.
Or we could design a ad-hoc encoding scheme where:
Escape = 1
Control = 2
Meta = 4
Alt = 8
Shift = 16
super = 32
Hyper = 64
And a key choard would be encoded as
CAN(24) c(99) <modifiers> <character>
with <modifiers> being the sum of the codes of the modifier keys that
are pressed, and <character> being the ASCII code of the graphic
character.
So when you'd type C-M-S-x, xterm would send: 24 99 22 120
This would be interpreted by emacs as: C-x c C-v x
and it could be bound to a distinct command from a keymap for C-x c.
Or we could patch emacs to decode the protocol and translate the two
bytes following a C-x c into the corresponding key events.
--
__Pascal Bourguignon__ http://www.informatimago.com/
"You can tell the Lisp programmers. They have pockets full of punch
cards with close parentheses on them." --> http://tinyurl.com/8ubpf
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: How to make <shift> work with <control> in xterm?
2006-10-14 5:01 How to make <shift> work with <control> in xterm? id.brep
2006-10-14 6:00 ` Pascal Bourguignon
2006-10-14 7:06 ` Harald Hanche-Olsen
@ 2006-10-14 18:40 ` Ilya Zakharevich
2 siblings, 0 replies; 6+ messages in thread
From: Ilya Zakharevich @ 2006-10-14 18:40 UTC (permalink / raw)
[A complimentary Cc of this posting was sent to
<id.brep@gmail.com>], who wrote in article <1160802062.842063.186330@i42g2000cwa.googlegroups.com>:
> In the emacs manual, it's said:
>
> On ASCII terminals, there are only 32 possible control characters.
> These are the control variants of letters and `@[]\^_'. In addition,
> the shift key is meaningless with control characters: `C-a' and `C-A'
> are the same character, and Emacs cannot distinguish them.
>
> I use xterm, I think it's graphical terminal, is it possibleto make
> <shit>
> work with <control> in xterm?
With special keys, it should work out-of-the-box (with sufficiently
new xterm) [of course, Emacs is (was?) too stupid to support keys with
modifiers out-of-the box; if current one is still that stupid, see
ilyaz.org/software/emacs, look for `key' `modifier' in customization files].
With ASCII key, if Thomas suggestion on modify-other-keys does not
help, you may want to add xterm keybindings which would send, e.g.,
C-x @ c A for C-S-a etc.
Hope this helps,
Ilya
^ permalink raw reply [flat|nested] 6+ messages in thread