[kbd] man keymaps
kalle at projektwerkstatt.de
Sun Jul 23 08:51:38 MSK 2017
I have some improvement proposals or unclear points (where explanation
could be improved) for the man 5 keymaps page.
*It would make sense to explain the term 'charset' somewhere
what for is the code produced by a keysym ? How is it related to
*it would make sense to explain basic terms at the beginning of the
page, e.g. charset, keysym, key(scan-)code
*keysym: what does the term stand for? why 'symbol'? what does 'keyboard
actions' mean? is keyboard induced action possibly better? how is this
set of actions related to the specific kernel (driver?)?
*'outputting character codes' -> explain more precisely what is meant
here by 'character codes'
*first the term 'keysyms' should be explained in detail, before
explaining special keysyms as modifiers are, e.g. the section "keysyms
can be given in decimal, octal" should be before the modifier part
*the modifier-part is in my opinion badly explained - I roughly propose
to every key there are 2^8=256 (?) possibilities/modes of outputting
symbols (defined by the kernel driver?)
The 2^8 modes can be represented by eight binary digits, or interpreted
as a binary number with 8 (?) digits, e.g. 010000101. The first digit
standing , the last one for units of 2^0=1, in this example
The different digits are called modifiers, since by combination of all
their different states (0 or 1) they are able to produce 256 (?) modes,
where the default one is when all modifiers are off (=0) so 00000000
binary is also 0 decimal number. These modifiers are keysyms thus their
state can be changed by typing some keys and out of historical
development have been given following names:
modifier name power of 2 decimal value
Shift 0 1
AltGr Alternate Graph 1 2
Control 2 4
Alt 3 8
ShiftL left Shift key 4 16
ShiftR right Shift key 5 32
CtrlL left Control key6 64
CtrlR right Control k.7 128
CapsShift 8 256
*I don't understand the example of the part starting with "Note that you
should be very careful[…]",because it tells that the Control modifier
stays switched on, until it is produced again by typing in the same key.
*To the sentence "these are actually being defined" add "by the map
specification line, see above"
*to "it has a special meaning" add: "to loadkeys (1)"?
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