Merge branch 'add-nix' into 'master'

Add nix package manager support.

See merge request !5

plugins.md

@@ -164,6 +164,7 @@ Since Ion does not support autocompletion via plugins, a lot of oh-my-zsh plugin
 | mysql-macports           | Done                           |
 | n98-magerun              | Not sure                       |
 | nanoc                    | Not sure                       |
+| nim                      | Done                           |
 | ng                       | Not happening                  |
 | nmap                     | Done                           |
 | node                     | Not sure                       |

tools/nix.ion

+# This plugin is based on the nix plugin for elvish.
+# It doesn't leave any functions, only sets up the profile and sets the appropriate
+# environment variables.
+
+fn setup_nix
+	# Only execute this file once per shell.
+	if test -n $or(${__ETC_PROFILE_NIX_SOURCED} "")
+		break
+	end
+	export __ETC_PROFILE_NIX_SOURCED=1
+
+	# Set up secure multi-user builds: non-root users build through the
+	# Nix daemon.
+	if test "$USER" != root || not test -w /nix/var/nix/db
+		export NIX_REMOTE=daemon
+	end
+
+	export NIX_USER_PROFILE_DIR="/nix/var/nix/profiles/per-user/$USER"
+	let nix_profiles = [ "/nix/var/nix/profiles/default" "$HOME/.nix-profile" ]
+	export NIX_PROFILES=$join(nix_profiles)
+
+	# Set up the per-user profile.
+	mkdir -m 0755 -p $NIX_USER_PROFILE_DIR
+	if not test -O "$NIX_USER_PROFILE_DIR"
+		echo "WARNING: bad ownership on $NIX_USER_PROFILE_DIR"
+	end
+
+	if test -w $HOME
+	  if not test -L $HOME/.nix-profile
+		  if test "$USER" != root
+			  ln -s $NIX_USER_PROFILE_DIR/profile $HOME/.nix-profile
+		  else
+			  # Root installs in the system-wide profile by default.
+			  ln -s /nix/var/nix/profiles/default $HOME/.nix-profile
+		  end
+	  end
+
+	  # Subscribe the root user to the NixOS channel by default.
+	  if test "$USER" = root && not test -e $HOME/.nix-channels
+		  echo "https://nixos.org/channels/nixpkgs-unstable nixpkgs" > $HOME/.nix-channels
+	  end
+
+	  # Create the per-user garbage collector roots directory.
+	  let NIX_USER_GCROOTS_DIR=/nix/var/nix/gcroots/per-user/$USER
+	  mkdir -m 0755 -p $NIX_USER_GCROOTS_DIR
+	  if not test -O "$NIX_USER_GCROOTS_DIR"
+		  echo "WARNING: bad ownership on $NIX_USER_GCROOTS_DIR"
+	  end
+
+	  # Set up a default Nix expression from which to install stuff.
+	  if not test -e $HOME/.nix-defexpr || test -L $HOME/.nix-defexpr
+		  rm -f $HOME/.nix-defexpr
+		  mkdir -p $HOME/.nix-defexpr
+		  if test "$USER" != root
+			  ln -s /nix/var/nix/profiles/per-user/root/channels $HOME/.nix-defexpr/channels_root
+		  end
+	  end
+	end
+
+
+	# Set $NIX_SSL_CERT_FILE so that Nixpkgs applications like curl work.
+	if not test -z $or(${NIX_SSL_CERT_FILE} "")
+		: # Allow users to override the NIX_SSL_CERT_FILE
+	else if test -e /etc/ssl/certs/ca-certificates.crt # NixOS, Ubuntu, Debian, Gentoo, Arch
+		export NIX_SSL_CERT_FILE=/etc/ssl/certs/ca-certificates.crt
+	else if test -e /etc/ssl/ca-bundle.pem # openSUSE Tumbleweed
+		export NIX_SSL_CERT_FILE=/etc/ssl/ca-bundle.pem
+	else if test -e /etc/ssl/certs/ca-bundle.crt # Old NixOS
+		export NIX_SSL_CERT_FILE=/etc/ssl/certs/ca-bundle.crt
+	else if test -e /etc/pki/tls/certs/ca-bundle.crt # Fedora, CentOS
+		export NIX_SSL_CERT_FILE=/etc/pki/tls/certs/ca-bundle.crt
+	else
+	  # Fall back to what is in the nix profiles, favouring whatever is defined last.
+	  for i in @nix_profiles
+		if test -e $i/etc/ssl/certs/ca-bundle.crt
+		  export NIX_SSL_CERT_FILE=$i/etc/ssl/certs/ca-bundle.crt
+		end
+	  end
+	end
+
+	export NIX_PATH="nixpkgs=/nix/var/nix/profiles/per-user/root/channels/nixpkgs:/nix/var/nix/profiles/per-user/root/channels"
+	export PATH="$HOME/.nix-profile/bin:/nix/var/nix/profiles/default/bin:$PATH"
+end
+
+setup_nix
+
+drop setup_nix