I think NixOS is great, but can't figure out how to build a package from source. Understanding the Nix expression language is not the problem, but to know what to put in a default.nix in order to build a package.
Take for example the Nix expression for gedit:
{ stdenv, intltool, fetchurl, enchant, isocodes, pkgconfig, gtk3, glib, bash, wrapGAppsHook, itstool, libsoup, libxml2, gnome3, librsvg, gdk_pixbuf, file, gspell }:stdenv.mkDerivation rec { inherit (import ./src.nix fetchurl) name src; propagatedUserEnvPkgs = [ gnome3.gnome_themes_standard ]; nativeBuildInputs = [ pkgconfig wrapGAppsHook ]; buildInputs = [ gtk3 glib intltool itstool enchant isocodes gdk_pixbuf gnome3.defaultIconTheme librsvg libsoup gnome3.libpeas gnome3.gtksourceview libxml2 gnome3.gsettings_desktop_schemas gnome3.dconf file gspell ]; enableParallelBuilding = true; preFixup = '' gappsWrapperArgs+=(--prefix LD_LIBRARY_PATH : "${stdenv.lib.makeLibraryPath [ gnome3.libpeas gnome3.gtksourceview ]}")''; meta = with stdenv.lib; { homepage = https://wiki.gnome.org/Apps/Gedit; description = "Official text editor of the GNOME desktop environment"; maintainers = gnome3.maintainers; license = licenses.gpl2; platforms = platforms.linux; };}How can someone arrive to this solution? I must be missing something.