add basic darwin-option command

pkgs/nix-tools/darwin-option.sh

@@ -5,8 +5,54 @@ export PATH=@path@:$PATH
 
 
 showSyntax() {
-    echo "$0: not implemented" >&2
-    exit 1
+  echo "$0: not implemented" >&2
+  exit 1
 }
 
-showSyntax
+evalNix() {
+  nix-instantiate --eval --strict -E "with import <darwin> {}; $@"
+}
+
+evalAttrs() {
+  evalNix "builtins.concatStringsSep \"\n\" (builtins.attrNames $@)"
+}
+
+evalOpt() {
+  evalNix "options.$option.$@" || true
+}
+
+# Parse the command line.
+origArgs=("$@")
+option=
+
+while [ "$#" -gt 0 ]; do
+  i="$1"; shift 1
+  case "$i" in
+    --help)
+      showSyntax
+      ;;
+    *)
+      option="$i"
+      ;;
+  esac
+done
+
+if [ -z "$option" ]; then showSyntax; fi
+
+if [ "$(evalOpt "_type" 2> /dev/null)" = '"option"' ]; then
+  echo "Value:"
+  evalOpt "value"
+  echo
+  echo "Default:"
+  evalOpt "default"
+  echo
+  echo "Example:"
+  evalOpt "example"
+  echo
+  echo "Description:"
+  eval printf $(evalOpt "description")
+  echo
+else
+  eval printf $(evalAttrs "options.$option")
+  echo
+fi

pkgs/nix-tools/darwin-rebuild.sh

@@ -5,8 +5,8 @@ export PATH=@path@:$PATH
 
 
 showSyntax() {
-    exec man darwin-rebuild
-    exit 1
+  exec man darwin-rebuild
+  exit 1
 }
 
 # Parse the command line.
@@ -14,47 +14,47 @@ origArgs=("$@")
 action=
 
 while [ "$#" -gt 0 ]; do
-    i="$1"; shift 1
-    case "$i" in
-        --help)
-          showSyntax
-          ;;
-        switch|build)
-          action="$i"
-          ;;
-        *)
-          echo "$0: unknown option \`$i'"
-          exit 1
-          ;;
-    esac
+  i="$1"; shift 1
+  case "$i" in
+    --help)
+      showSyntax
+      ;;
+    switch|build)
+      action="$i"
+      ;;
+    *)
+      echo "$0: unknown option \`$i'"
+      exit 1
+      ;;
+  esac
 done
 
 if [ -z "$action" ]; then showSyntax; fi
 
 echo "building the system configuration..." >&2
 if [ "$action" = switch -o "$action" = build ]; then
-    systemConfig="$(nix-build '<darwin>' --no-out-link -A system)"
+  systemConfig="$(nix-build '<darwin>' --no-out-link -A system)"
 fi
 
 if [ "$action" = build ]; then
-    echo $systemConfig
+  echo $systemConfig
 fi
 
 
 if [ "$action" = switch ]; then
-    profileDir=$(dirname @profile@)
+  profileDir=$(dirname @profile@)
 
-    if [ "$USER" != root -a ! -w $profileDir ]; then
-        sudo nix-env -p @profile@ --set $systemConfig
-    else
-        nix-env -p @profile@ --set $systemConfig
-    fi
+  if [ "$USER" != root -a ! -w $profileDir ]; then
+    sudo nix-env -p @profile@ --set $systemConfig
+  else
+    nix-env -p @profile@ --set $systemConfig
+  fi
 
-    if [ "$USER" != root ]; then
-      sudo $systemConfig/activate
-    else
-      $systemConfig/activate
-    fi
+  if [ "$USER" != root ]; then
+    sudo $systemConfig/activate
+  else
+    $systemConfig/activate
+  fi
 
-    $systemConfig/activate-user
+  $systemConfig/activate-user
 fi