宋文武 <iyzs...@gmail.com> skribis: > Ludovic Courtès <l...@gnu.org> writes: > >> 宋文武 <iyzs...@gmail.com> skribis: >> >>> Ludovic Courtès <l...@gnu.org> writes: >>> >>>> Adam Pribyl <pri...@lowlevel.cz> skribis:
[...] >>> I just put it in my config.scm: >>> >>> (define (console-layout-service layout) >>> (with-monad %store-monad >>> (return >>> (service >>> (document "Setup keyboard layout for console") >>> (provision '(console-layout)) >>> (start #~(lambda _ >>> (system* (string-append #kbd "/bin/loadkeys") #$layout))) >>> (stop #~(const #t)) >>> (respawn? #f))))) >> >> Excellent. I was thinking that we should have a keyboard layout setting >> in the OS declaration, that would lead to a service like the one above >> as well as the appropriate X settings. > Currently, operating-system is not declarative, with the setting: > (operating-system > (keymap "dvorak")) > IIUC, the xorg-server service can't see it unless passed explicitly. Right. > In NixOS, declarative configuration is implemented by 'modules': > https://nixos.org/wiki/NixOS:Modules > > Every module can define some options, access and contrib to the config, > the configuration.nix is just a normal module provided by user. > > Yeah, how all the modules eval toghether is still a mystery for me. Yes, that’s the whole point. I don’t want an ‘mkIf’ here. ;-) There are several issues here. 1. Is it desirable for any service to be able to touch any part of the OS configuration, as is the case in NixOS? I’m not sure. On one hand, it’s useful in situations like the one above; on the other hand, it feels like each service definition would get more authority than it really needed. Currently, the <service> type has fields such as ‘user-accounts’ and ‘pam-services’ for that reason: a service can add new accounts or PAM services, but does not access the global OS config. These would not be needed if services had access to the global config. 2. Services typically need to be able to add files to the store, etc. Currently, that means that services must be monadic values in the store monad. This is slightly annoying, because indeed it makes it feel “less declarative.” 3. In NixOS there’s no type checking: one can just add fields to the global configuration attribute set, and they may be picked up by service definitions. Here, ‘operating-system’ is a well-defined type, and service-specific options are passed as arguments to procedures that implement the service. Just random thoughts. :-) I feel there are things we can improve, but it’s not completely clear how yet. Thanks, Ludo’.
