diff --git a/optparse.lua b/optparse.lua
new file mode 100644
index 0000000..e1b451c
--- /dev/null
+++ b/optparse.lua
@@ -0,0 +1,203 @@
+--
+-- Lua command line option parser.
+-- Interface based on Pythons optparse.
+-- http://docs.python.org/lib/module-optparse.html
+-- (c) 2008 David Manura, Licensed under the same terms as Lua (MIT license)
+--
+-- To be used like this:
+-- t={usage="<some usage message>", version="<version string>"}
+-- op = xlua.OptionParser(t)
+-- op:option{"<opt>", action=<action>, dest=<dest>, help="<help message for this option>"}
+--
+-- with :
+--   <opt> the option string to be used (can be anything, if one letter opt, then should be -x val, more letters: -xy=val )
+--   <action> one of
+--   - store: store in options as key, val
+--   - store_true: stores key, true
+--   - store_false: stores key, false
+--   <dest> is the key under which the option is saved
+--
+-- options,args = op.parse_args()
+--
+-- now options is the table of options (key, val) and args is the table with non-option arguments.
+-- You can use op.fail(message) for failing and op.help() for printing the usage as you like.
+--
+-- modifed by Benoit Corda, Clement Farabet
+--
+
+OptionParser = {}
+
+function OptionParser:new(t)
+   local self = {}
+   self.usage = t.usage
+   self.oneliner = t.oneliner
+   self.option_descriptions = {}
+   self.option_of = {}
+   for k,v in pairs(OptionParser) do
+      self[k] = v
+   end
+   self:option{"-h", "--help", action="store_true", dest="help",
+               help="show this help message and exit"}
+   return self
+end
+
+function OptionParser:fail(s) -- extension
+   io.stderr:write(s .. '\n')
+   self:help()
+   os.exit(1)
+end
+
+function OptionParser:option(optdesc)
+   self.option_descriptions[#self.option_descriptions+1] = optdesc
+   for _,v in ipairs(optdesc) do
+      self.option_of[v] = optdesc
+   end
+end
+
+function OptionParser:parse(options)
+   local options = options or {}
+   local args = {}
+
+   -- set the default
+   for _,v in ipairs(self.option_descriptions) do
+      if v.default ~= nil and options[v.dest]==nil then
+         options[v.dest] = v.default
+      end
+   end
+
+   if not arg then
+      options.__main__ = false -- python like main
+      self.options = options
+      return options, args
+   end
+   options.__main__ = true -- python like main
+
+   -- expand options (e.g. "--input=file" -> "--input", "file")
+   local arg = {unpack(arg)}
+   for i=#arg,1,-1 do local v = arg[i]
+      local flag, val = v:match('^(%-%-%w+)=(.*)')
+      if flag then
+         arg[i] = flag
+         table.insert(arg, i+1, val)
+      end
+   end
+
+   local i = 1
+   while i <= #arg do
+      local v = arg[i]
+      local optdesc = self.option_of[v]
+      if optdesc then
+         local default = optdesc.default
+         local action = optdesc.action
+         local val = default
+         if action == 'store' or action == nil then
+            i = i + 1
+            val = arg[i] or default
+            if not val then self:fail('option requires an argument ' .. v) end
+         elseif action == 'store_true' then
+            val = true
+         elseif action == 'store_false' then
+            val = false
+         end
+         options[optdesc.dest] = val
+      else
+         if v:match('^%-') then self:fail('invalid option ' .. v) end
+         args[#args+1] = v
+      end
+      i = i + 1
+   end
+   for k,opt in pairs(self.option_of) do
+      if opt.req and not options[opt.dest] then
+         self:fail('option '.. k .. ' requires an argument ')
+      end
+   end
+   if options.help then
+      self:help()
+      os.exit()
+   end
+   -- set the default if nil
+   self.options = options
+   return options, args
+end
+
+function OptionParser:flags(optdesc)
+   local sflags = {}
+   local action = optdesc and optdesc.action
+   for _,flag in ipairs(optdesc) do
+      local sflagend
+      if action == nil or action == 'store' then
+         local metavar = optdesc.metavar or optdesc.dest:upper()
+         sflagend = #flag == 2 and ' ' .. metavar
+            or  '=' .. metavar
+      else
+         sflagend = ''
+      end
+      sflags[#sflags+1] = flag .. sflagend
+   end
+   return table.concat(sflags, ', ')
+end
+
+function OptionParser:help()
+   io.stdout:write(self.oneliner .. "\n")
+   if arg[-1] then
+      io.stdout:write("Usage: " .. self.usage:gsub('%%prog', (arg[-1] .. ' ' .. arg[0])) .. "\n")
+   elseif arg[0] then
+      io.stdout:write("Usage: " .. self.usage:gsub('%%prog', arg[0]) .. "\n")
+   else
+      io.stdout:write("Usage: " .. self.usage:gsub('%%prog', 'THISPROG') .. "\n")
+   end
+   io.stdout:write("\n")
+   io.stdout:write("Options:\n")
+   pad = 0
+   for _,optdesc in ipairs(self.option_descriptions) do
+      pad = math.max(pad, #self:flags(optdesc))
+   end
+   for _,optdesc in ipairs(self.option_descriptions) do
+      local defstr = ''
+      if optdesc.req then
+         defstr = ' [REQUIRED]'
+      elseif optdesc.default then
+         defstr = ' [default = ' .. tostring(optdesc.default) .. ']'
+      end
+      io.stdout:write("  " .. self:flags(optdesc) ..
+                   string.rep(' ', pad - #self:flags(optdesc)) ..
+                "  " .. optdesc.help .. defstr .. "\n")
+   end
+end
+
+function OptionParser:tostring(generatefilename, params)
+   local str = ''
+   if not generatefilename then
+      str = '<'.. ((arg and arg[0]) or 'interpreted.lua'):gsub('.lua','') .. "> configuration:\n"
+      for k,v in pairs(self.options) do
+         str = str .. ' + ' .. k .. ' = ' .. tostring(v) .. '\n'
+      end
+   else
+      local first = true
+      for i,entry in ipairs(self.option_descriptions) do
+         local key = entry[1]
+         local match = true
+         if #params > 0 then
+            match = false
+            for i,param in ipairs(params) do
+               if key == param then match = true; break end
+            end
+         end
+         local val = self.options[entry.dest]
+         if val and match then
+            if first then
+               str = str .. key .. '=' .. tostring(val)
+            else
+               str = str .. ',' .. key .. '=' .. tostring(val)
+            end
+            first = false
+         end
+      end
+      str = str:gsub('/','|'):gsub(' ','_')
+   end
+   return str
+end
+
+function OptionParser:summarize(compact)
+   io.write(self:tostring(compact))
+end