Makes Dutch language file default to U.S. keyboard layout

[Wengier]

This intends to solve #1951 as reported by @rderooy by making the Dutch language file default to the U.S. keyboard layout, since as mentioned in the issue Dutch keyboard layouts are very rarely used in the Netherlands.

[rderooy]

I did a test with this patch, and indeed it keeps the US layout. But it also causes this error in the log:

LAYOUT: Failed loading codepage 850 for detected language nl

In addition to testing with nl_NL.UTF-8 as locale, I tested with:

LANG=nl_BE.UTF-8 dosbox

This is the Belgium Dutch (Flemish) locale. This also came up with a US layout, which is actually not correct as it should use the Belgium layout.

For those not in the know, Belgium has three locales. nl_BE.UTF-8, fr_BE.UTF-8 and de_BE.UTF-8. Basically Dutch, French and German. But all 3 use the same French-style keyboard layout (AZERTY).

[rderooy]

Some further testing reveals more issues with keyboard layouts.

Switzerland has 4 locales and 2 keyboard layouts (Swiss-German and Swiss-French). When starting with
LANG=de_CH.UTF-8 dosbox it gives a German keyboard layout, instead of Swiss-German (keyb sg), and a similar issue will occur with LANG=fr_CH.UTF-8 dosbox which will give a French keyboard, instead of Swiss-French (keyb sf).

Swiss-Italian (it_CH) should default to the Swiss-French keyboard, and Swiss-Romansh (rm_CH) should default to the Swiss-German keyboard.

And then you may think that a country as tiny as Luxembourg would be easy. It only has 2 locales (fr_LU and de_LU). But it does not have it's own keyboard layout. Instead it uses Belgium, French and German keyboards in addition to Swiss-French keyboards commonly found in schools and government institutions. Try to guess the layout...

[kcgen]

Currently the chunk of code that parses LANG= only takes the first-two letters (the language component), and skips the rest. This was a deliberate choice back when LANG's only purpose was load one of our 5 translations (de, es, it, po, ru).

This should be expanded into handling both the language and country components, and then flowed into the layout and other settings on start-up.

[kcgen]

Some further testing reveals more issues with keyboard layouts.

Switzerland has 4 locales and 2 keyboard layouts (Swiss-German and Swiss-French). When starting with LANG=de_CH.UTF-8 dosbox it gives a German keyboard layout, instead of Swiss-German (keyb sg), and a similar issue will occur with LANG=fr_CH.UTF-8 dosbox which will give a French keyboard, instead of Swiss-French (keyb sf).

Swiss-Italian (it_CH) should default to the Swiss-French keyboard, and Swiss-Romansh (rm_CH) should default to the Swiss-German keyboard.

And then you may think that a country as tiny as Luxembourg would be easy. It only has 2 locales (fr_LU and de_LU). But it does not have it's own keyboard layout. Instead it uses Belgium, French and German keyboards in addition to Swiss-French keyboards commonly found in schools and government institutions. Try to guess the layout...

@rderooy , right now only the language is fetched from the LANG= variable.

If we get the second country code from the LANG= as well, how should this play into these conf settings:

[dos]
#               country: Set DOS country code which will affect country-specific
#                        information such as date, time, and decimal formats.
#                        If set to 0, the country code corresponding to the
#                        selected keyboard layout will be used.
#        keyboardlayout: Language code of the keyboard layout (or none).

country               = 0
keyboardlayout        = auto

I think we want to follow the general software approach of "near/specific" variables trump "distant/general" variables.

So if the conf's country and keyboardlayout are defaults, then we try to derive these from the more general LANG env variable.

But if country and/or layout are customized inside the conf, then those should take priority over the LANG.

[rderooy]

Relying on the LANG variable to "guess" the keyboard layout is very much hit and miss. A few ways to check keyboard layout on Linux that I am aware of.

This seems to return the current keyboard layout, but requires X11 (or XWayland) to be present

$ setxkbmap -query
rules:      evdev
model:      pc105
layout:     us

This uses systemd, but returns the default "system" layout, and may not reflect the currently set layout for the user.

$ localectl
   System Locale: LANG=en_GB.UTF-8
       VC Keymap: us-euro
      X11 Layout: us,us
     X11 Variant: euro,intl
$ cat /etc/vconsole.conf 
KEYMAP="us-euro"
FONT="eurlatgr"

[Wengier]

@rderooy The log message LAYOUT: Failed loading codepage 850 for detected language nl will also not be shown with the updated code. Other issue(s) mentioned above probably go to separate PRs.

[kcgen]

Looks great, @Wengier!