I’m using Gnome 3 on NixOS and really like it. It includes a Software store that currently uses flatpak to install applications. However, as I understand it, other backends are possible and it seems that someone already tried but it bitrotted.
However, Nix has many advantages over flatpak. So I was thinking that it should be possible to make “streaming apps”: For all the *.desktop files that Hydra builds, autogenerate a wrapper *.desktop file that shows a window with the metadata of the package (including to-install-size), asking if the user wants to run it.
If the user clicks “Yes”, it updates something like the home-manager file and runs whatever manages it, and then launches it.
The wrapper desktop file should be installed in a location that has low precedence, or the wrappers list needs to be updated after every install.
This way, installing Nix means installing all the apps, immediately available, easily removed, automatically updated.