Thread View: comp.std.misc
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Started by Mark Shepard
Wed, 10 Apr 1991 22:11
[ novice questions ] KEYSYMs vs Unicode
Author: Mark Shepard
Date: Wed, 10 Apr 1991 22:11
Date: Wed, 10 Apr 1991 22:11
48 lines
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3474 bytes
All,
I'm interested in converting between X's KEYSYMs and Unicode, and have
some questions (below). I'm new to the Unicode world, so please bear with me.
0. How is Unicode different from X's KEYSYM standard (aside from being
more extensive)? What are the fundamental technical differences?
Unicode is a 16-bit encoding, and with one exception, X's KEYSYM std.
uses a 32-bit encoding with the upper 16-bits zero.
1. One difference in philosophy I can see is this: Unicode is a std. for
_character_ symbols, while KEYSYMs are a std. for _keyboard_ symbols.
So, KEYSYMs include codes for "Shift", "Caps_Lock", "Shift_Lock",
"Alt_R", "Alt_L", "Meta", "F1", "F2", ... "F10", "Do", "Select",
"Print_Screen", and "Up_Arrow". As far as I can tell, Unicode does
not attempt to represent these, yet Unicode _does_ include codes for
the traditional ASCII control-chars (NUL, SOH, STX, ETX, ..., BEL,
BackSpace, ..., LineFeed, VertTab, FormFeed, CarriageReturn ).
1a. If Unicode includes codes for "BackSpace", shouldn't it include codes
for more exotic functions such as "Alt_L" or "Meta"? If not, perhaps
Unicode shouldn't include "BackSpace" either...
Do the Unicode standard-makers see including "non-printable" chars such
"BackSpace" as a "good thing" or as a necessary evil?
1b. Is the area of "keyboard symbols" too broad to make a reasonable
standard? (Comments from anyone with KEYSYM experience would be very
welcome). In this case, I'm thinking about Unicode not in a traditional
sense (as a code for interchange between application programs),
but as a code for interchange between applications and keyboards
("symbol-oriented devices").
Can we write sophisticated Unicode-based applications w/o a standard
encoding for "FunctionKey1" or "Insert"?
1c. Is it possible to build a Unicode to KEYSYM translator?
(I realize some loss of information is bound to occur since the KEYSYM
std. can't represent all the characters which Unicode can. I'm most
interested in handling of keyboard-symbols such as "Shift").
1d. Is the reverse translation possible (KEYSYM to Unicode)?
(I think the answer here is "yes").
-(Thanx for any help) MarkS
Mark Shepard
DEC's Workstation Systems Engineering, Palo Alto
shepard@decpa.pa.dec.com || shepard@gatekeeper.dec.com
+1.415.853.6685
Re: [ novice questions ] KEYSYMs vs Unicode
Author: Peter da Silva
Date: Fri, 12 Apr 1991 15:49
Date: Fri, 12 Apr 1991 15:49
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In article <SHEPARD.91Apr10171132@finch.pa.dec.com> shepard@finch.pa.dec.com (Mark Shepard) writes: > 0. How is Unicode different from X's KEYSYM standard (aside from being > more extensive)? What are the fundamental technical differences? KEYSYMS is an input standard. Unicode is an output standard. > 1a. If Unicode includes codes for "BackSpace", shouldn't it include codes > for more exotic functions such as "Alt_L" or "Meta"? No, because they have a different context. More appropriate would be to ask why there are no codes for "underscore", "boldface", and so on. Of course, these are covered (in the U.S.) by ANSI X3.64. > 1b. Is the area of "keyboard symbols" too broad to make a reasonable > standard? Probably not, but how broad would you want it? You want depress and release information, with time-stamps, etc...? > Can we write sophisticated Unicode-based applications w/o a standard > encoding for "FunctionKey1" or "Insert"? How about "page down" or "left-amiga" or "open-apple"? How about "compose", "select", "extend-char"? How about "graph-cursor" or "alpha display"? These are all "standard" keys on one or more lines of keyboards. -- Peter da Silva. `-_-' peter@ferranti.com +1 713 274 5180. 'U` "Have you hugged your wolf today?"
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