Support Unicode keymappings

Changes

• implemented basic UTF-8 parsing
• commands are parsed as UTF-8
• non-ASCII keys can be buffered

Description

This merge request brings the ability to map non-Latin characters without manually listing them in callbacks.c. It is now possible to map them as normal characters like in various terminal programs. This should hopefully solve #9 (closed) (and various duplicates), which has been open for 3 years already.

The Nuklear's UTF-8 handling code was used as a reference for helpers in utf8.{c,h}. Now the Glib's UTF-8 functions are used instead.

Examples

Here is an example zathurarc with mappings for Russian keyboard layout, which I wrote to demonstrate how this can be used, and I actually use this zathurarc currently myself:

150+ lines

map й feedkeys q
map ц feedkeys w
map у feedkeys e
map к feedkeys r
map е feedkeys t
map н feedkeys y
map г feedkeys u
map ш feedkeys i
map щ feedkeys o
map з feedkeys p
# Feedkeys can't do this
map х feedkeys [
# Feedkeys can't do this
map ъ feedkeys ]
map ф feedkeys a
map ы feedkeys s
map в feedkeys d
map а feedkeys f
map п feedkeys g
# This is needed because the first "п" is immediately replaced with "g",
# but subsequent keys stay unmodified
map gп feedkeys gg
map р feedkeys h
map о feedkeys j
map л feedkeys k
map д feedkeys l
map ж feedkeys ;
map э feedkeys "'"
map я feedkeys z
# See comment for "gп" above
map zя feedkeys zz
map ч feedkeys x
map с feedkeys c
map м feedkeys v
map и feedkeys b
map т feedkeys n
map ь feedkeys m
# Feedkeys can't do this
map б feedkeys ,
# Feedkeys can't do this
map ю feedkeys .
# FIXME: "feedkeys `" always works as "feedkeys ~" for some reason
map ё feedkeys `
map Й feedkeys <S-q>
map Ц feedkeys <S-w>
map У feedkeys <S-e>
map К feedkeys <S-r>
map Е feedkeys <S-t>
map Н feedkeys <S-y>
map Г feedkeys <S-u>
map Ш feedkeys <S-i>
map Щ feedkeys <S-o>
map З feedkeys <S-p>
# Feedkeys can't do this
map Х feedkeys {
# Feedkeys can't do this
map Ъ feedkeys }
map Ф feedkeys <S-a>
map Ы feedkeys <S-s>
map В feedkeys <S-d>
map А feedkeys <S-f>
map П feedkeys <S-g>
map Р feedkeys <S-h>
map О feedkeys <S-j>
map Л feedkeys <S-k>
map Д feedkeys <S-l>
map Ж feedkeys :
map Э feedkeys '"'
map Я feedkeys <S-z>
map Ч feedkeys <S-x>
map С feedkeys <S-c>
map М feedkeys <S-v>
map И feedkeys <S-b>
map Т feedkeys <S-n>
map Ь feedkeys <S-m>
map Б feedkeys <
map Ю feedkeys >
map Ё feedkeys ~
map <C-й> feedkeys <C-q>
map <C-ц> feedkeys <C-w>
map <C-у> feedkeys <C-e>
map <C-к> feedkeys <C-r>
map <C-е> feedkeys <C-t>
map <C-н> feedkeys <C-y>
map <C-г> feedkeys <C-u>
map <C-ш> feedkeys <C-i>
map <C-щ> feedkeys <C-o>
map <C-з> feedkeys <C-p>
# Feedkeys can't do this
map <C-х> feedkeys <C-[>
# Feedkeys can't do this
map <C-ъ> feedkeys <C-]>
map <C-ф> feedkeys <C-a>
map <C-ы> feedkeys <C-s>
map <C-в> feedkeys <C-d>
map <C-а> feedkeys <C-f>
map <C-п> feedkeys <C-g>
map <C-р> feedkeys <C-h>
map <C-о> feedkeys <C-j>
map <C-л> feedkeys <C-k>
map <C-д> feedkeys <C-l>
map <C-ж> feedkeys <C-;>
# Feedkeys can't do this
map <C-э> feedkeys <C-"'">
map <C-я> feedkeys <C-z>
map <C-ч> feedkeys <C-x>
map <C-с> feedkeys <C-c>
map <C-м> feedkeys <C-v>
map <C-и> feedkeys <C-b>
map <C-т> feedkeys <C-n>
map <C-ь> feedkeys <C-m>
# Feedkeys can't do this
map <C-б> feedkeys <C-,>
# Feedkeys can't do this
map <C-ю> feedkeys <C-.>
map <A-й> feedkeys <A-q>
map <A-ц> feedkeys <A-w>
map <A-у> feedkeys <A-e>
map <A-к> feedkeys <A-r>
map <A-е> feedkeys <A-t>
map <A-н> feedkeys <A-y>
map <A-г> feedkeys <A-u>
map <A-ш> feedkeys <A-i>
map <A-щ> feedkeys <A-o>
map <A-з> feedkeys <A-p>
# Feedkeys can't do this
map <A-х> feedkeys <A-[>
# Feedkeys can't do this
map <A-ъ> feedkeys <A-]>
map <A-ф> feedkeys <A-a>
map <A-ы> feedkeys <A-s>
map <A-в> feedkeys <A-d>
map <A-а> feedkeys <A-f>
map <A-п> feedkeys <A-g>
map <A-р> feedkeys <A-h>
map <A-о> feedkeys <A-j>
map <A-л> feedkeys <A-k>
map <A-д> feedkeys <A-l>
map <A-ж> feedkeys <A-;>
# Feedkeys can't do this
map <A-э> feedkeys <A-"'">
map <A-я> feedkeys <A-z>
map <A-ч> feedkeys <A-x>
map <A-с> feedkeys <A-c>
map <A-м> feedkeys <A-v>
map <A-и> feedkeys <A-b>
map <A-т> feedkeys <A-n>
map <A-ь> feedkeys <A-m>
# Feedkeys can't do this
map <A-б> feedkeys <A-,>
# Feedkeys can't do this
map <A-ю> feedkeys <A-.>

This config is semi-auto-generated, so some (or even most?) mappings probably do nothing, and several mappings may still be missing. As you can see, there are still some quirks (mainly from how feedkeys works), but it works.

The other example would be the situation mentioned by @roman a week ago, where you want to map extra keys on your keyboard that produce Unicode characters directly to some actions:

map ← scroll left
map ↓ scroll down
map ↑ scroll up
map → scroll right