replace parser with argparse

bookmobile

@@ -30,7 +30,7 @@ function usage
   echo "    -t THEME   Set theme for reader format. Default: medium"
   echo "               Theme options: " 
   for theme in themes/*.css
-      echo (string replace -r '\.[^\.]+$' '' (basename $theme))
+      echo "              " (string replace -r '\.[^\.]+$' '' (basename $theme))
   end
   echo ""
   echo "    --format FORMAT" 
@@ -44,24 +44,26 @@ function usage
 end
 
 function check_args
-  for current_arg in (seq 1 (count $argv))
-    set next_arg $argv[(math $current_arg + 1)]
+  argparse h/help t/theme= f/format= o/output= -- $argv
+  or exit 1
 
-    switch $argv[$current_arg]
-    case -h --help
+  if set -q _flag_help
       usage
-      break
-    case -t --theme
-      echo "theme: " $next_arg
-      set -g theme themes/$next_arg.css 
-    case -f --format
-      echo "format: " $next_arg
-      set -g format $next_arg
-    case -o --output
-      echo "output: " $next_arg
-      set -g output $next_arg
-    end
+      exit
   end
+
+  if set -q _flag_t
+    set theme themes/$_flag_theme.css
+  end
+
+  if set -q _flag_f
+    set format $_flag_format
+  end
+
+  if set -q _flag_o
+    set output $_flag_output
+  end
+
 end
 
 function set_metadata