diff --git a/rockspecs/largparse-0.1-1.rockspec~ b/rockspecs/largparse-0.1-1.rockspec~
new file mode 100644
index 0000000..b93aae8
--- /dev/null
+++ b/rockspecs/largparse-0.1-1.rockspec~
@@ -0,0 +1,22 @@
+package = "largparse"
+version = "git-1"
+source = {
+   url = "src"
+}
+description = {
+   summary = "*** please specify description summary ***",
+   detailed = "*** please enter a detailed description ***",
+   homepage = "*** please enter a project homepage ***",
+   license = "MIT/X11"
+}
+dependencies = {
+   "lua >= 5.1, < 5.3",
+   "30log >= 0.6"
+}
+build = {
+   type = "builtin",
+   modules = {
+      largparse = "src/largparse.lua",
+      ["largparse.state"] = "src/state.lua"
+   }
+}
diff --git a/rockspecs/largparse-wip-1.rockspec b/rockspecs/largparse-wip-1.rockspec
new file mode 100644
index 0000000..a3323e4
--- /dev/null
+++ b/rockspecs/largparse-wip-1.rockspec
@@ -0,0 +1,22 @@
+package = "largparse"
+version = "wip-1"
+source = {
+   url = "src"
+}
+description = {
+   summary = "*** please specify description summary ***",
+   detailed = "*** please enter a detailed description ***",
+   homepage = "*** please enter a project homepage ***",
+   license = "MIT/X11"
+}
+dependencies = {
+   "lua >= 5.1, < 5.3",
+   "30log >= 0.6"
+}
+build = {
+   type = "builtin",
+   modules = {
+      largparse = "src/largparse.lua",
+      ["largparse.state"] = "src/state.lua"
+   }
+}
diff --git a/src/largparse.lua b/src/largparse.lua
new file mode 100644
index 0000000..1ea46b1
--- /dev/null
+++ b/src/largparse.lua
@@ -0,0 +1,297 @@
+local largparse = {}
+
+local class = require "30log"
+
+local State = require "largparse.state"
+
+local Parser = class()
+
+function Parser:__init(options)
+   options = options or {}
+   self.description = options.description
+   self.name = options.name
+   self.no_help = options.no_help
+   self.must_command = options.must_command
+
+   self.arguments = {}
+   self.elements = {}
+   self.groups = {}
+   self.commands = {}
+   self.context = {}
+end
+
+function Parser:add_alias(element, alias)
+   table.insert(element.aliases, alias)
+   self.context[alias] = element
+end
+
+function Parser:apply_options(element, options)
+   for k, v in pairs(options) do
+      element[k] = v -- fixme
+   end
+end
+
+function Parser:make_target(element)
+   if not element.target then
+      for _, alias in ipairs(element.aliases) do
+         if alias:match "^%-%-" then
+            element.target = alias:sub(3)
+            return
+         end
+      end
+
+      element.target = element.aliases[1]:match "^%-*(.*)"
+   end
+end
+
+function Parser:parse_boundaries(boundaries)
+   if tonumber(boundaries) then
+      return tonumber(boundaries), tonumber(boundaries)
+   end
+
+   if boundaries == "*" then
+      return 0, math.huge
+   end
+
+   if boundaries == "+" then
+      return 1, math.huge
+   end
+
+   if boundaries == "?" then
+      return 0, 1
+   end
+
+   if boundaries:match "^%d+%-%d+$" then
+      local min, max = boundaries:match "^(%d+)%-(%d+)$"
+      return tonumber(min), tonumber(max)
+   end
+
+   if boundaries:match "^%d+%+$" then
+      local min = boundaries:match "^(%d+)%+$"
+      return tonumber(min), math.huge
+   end
+end
+
+-- TODO: make it declarative as it was
+function Parser:argument(name, ...)
+   local element = {
+      name = name,
+      aliases = {},
+      count = 1,
+      args = 1,
+      type = "argument"
+   }
+
+   self:add_alias(element, name)
+
+   local argument
+   for i = 1, select('#', ...) do
+      argument = select(i, ...)
+
+      if type(argument) == "string" then
+         self:add_alias(element, argument)
+      else
+         self:apply_options(element, argument)
+      end
+   end
+
+   self:make_target(element)
+
+   element.mincount, element.maxcount = self:parse_boundaries(element.count)
+   element.minargs, element.maxargs = self:parse_boundaries(element.args)
+   if element.minargs == 0 then
+      element.mincount = 0
+   end
+
+   table.insert(self.arguments, element)
+   table.insert(self.elements, element)
+
+   return element
+end
+
+function Parser:option(name, ...)
+   local element = {
+      name = name,
+      aliases = {},
+      count = "0-1",
+      args = 1,
+      type = "option"
+   }
+
+   self:add_alias(element, name)
+
+   local argument
+   for i = 1, select('#', ...) do
+      argument = select(i, ...)
+
+      if type(argument) == "string" then
+         self:add_alias(element, argument)
+      else
+         self:apply_options(element, argument)
+      end
+   end
+
+   self:make_target(element)
+
+   element.mincount, element.maxcount = self:parse_boundaries(element.count)
+   element.minargs, element.maxargs = self:parse_boundaries(element.args)
+
+   table.insert(self.elements, element)
+
+   return element
+end
+
+-- DRY?
+
+function Parser:flag(name, ...)
+   local element = {
+      name = name,
+      aliases = {},
+      count = "0-1",
+      args = 0,
+      type = "option"
+   }
+
+   self:add_alias(element, name)
+
+   local argument
+   for i = 1, select('#', ...) do
+      argument = select(i, ...)
+
+      if type(argument) == "string" then
+         self:add_alias(element, argument)
+      else
+         self:apply_options(element, argument)
+      end
+   end
+
+   self:make_target(element)
+
+   element.mincount, element.maxcount = self:parse_boundaries(element.count)
+   element.minargs, element.maxargs = self:parse_boundaries(element.args)
+
+   table.insert(self.elements, element)
+
+   return element
+end
+
+function Parser:command(name, ...)
+   local element = {
+      name = name,
+      aliases = {},
+      count = "0-1",
+      args = 0,
+      type = "command"
+   }
+
+   local command = Parser() -- fixme
+   for k, v in pairs(element) do
+      command[k] = v
+   end
+
+   self:add_alias(command, name)
+
+   local argument
+   for i = 1, select('#', ...) do
+      argument = select(i, ...)
+      self:add_alias(command, argument)
+   end
+
+   self:make_target(command)
+
+   command.mincount, command.maxcount = self:parse_boundaries(command.count)
+   command.minargs, command.maxargs = self:parse_boundaries(command.args)
+
+   table.insert(self.elements, command)
+
+   return command
+end
+
+function Parser:group(...)
+   --
+end
+
+function Parser:mutually_exclusive(...)
+   local group = {
+      elements = {...}
+   }
+
+   table.insert(self.groups, group)
+   return group
+end
+
+function Parser:error(fmt, ...)
+   local msg = fmt:format(...)
+   io.stderr:write("Error: " .. msg .. "\n")
+   os.exit(1)
+end
+
+function Parser:assert(assertion, ...)
+   return assertion or self:error(...)
+end
+
+
+function Parser:parse(args)
+   args = args or arg
+   self.name = self.name or args[0]
+
+   local state = State(self)
+
+   local handle_options = true
+   for _, data in ipairs(args) do
+      local plain = true
+
+      if handle_options then
+         if data:sub(1, 1) == "-" then
+            if #data > 1 then
+               if data:sub(2, 2):match "[a-zA-Z]" then
+                  plain = false
+
+                  local name, element
+                  for i = 2, #data do
+                     name = "-" .. data:sub(i, i)
+                     element = self:assert(state.context[name], "unknown option " .. name)
+                     state:handle_option(name)
+
+                     if i ~= #data and not (element:can_take(0) and data:sub(i+1, i+1):match "[a-zA-Z]") then
+                        state:handle_argument(data:sub(i+1))
+                        break
+                     end
+                  end
+               elseif data:sub(2, 2) == "-" then
+                  if #data == 2 then
+                     plain = false
+                     handle_options = false
+                  elseif data:sub(3, 3):match "[a-zA-Z]" then
+                     plain = false
+
+                     local equal = data:find "="
+                     if equal then
+                        local name = data:sub(1, equal-1)
+                        local element = self:assert(state.context[name], "unknown option " .. name)
+                        self:assert(element.maxargs > 0, "option " .. name .. " doesn't take arguments")
+
+                        state:handle_option(data:sub(1, equal-1))
+                        state:handle_argument(data:sub(equal+1))
+                     else
+                        state:handle_option(data)
+                     end
+                  end
+               end
+            end
+         end
+      end
+
+      if plain then
+         state:handle_argument(data)
+      end
+   end
+
+   local result = state:get_result()
+
+   return result
+end
+
+largparse.parser = Parser
+
+return largparse
diff --git a/src/state.lua b/src/state.lua
new file mode 100644
index 0000000..5a6ab9b
--- /dev/null
+++ b/src/state.lua
@@ -0,0 +1,185 @@
+local class = require "30log"
+
+local State = class()
+
+function State:__init(parser)
+   self.context = {}
+   self._all_elements = {}
+   self._all_groups = {}
+   self:_switch(parser)
+
+   self._result = {}
+end
+
+function State:handle_option(name)
+   local option = self:_assert(self.context[name], "unknown option %s", name)
+
+   self:_open(option)
+end
+
+function State:handle_argument(data)
+   if self._current then
+      if self:_can_pass(self._current) then
+         self:_pass(self._current, data)
+         return
+      else
+         self._current = nil
+      end
+   end
+
+   local argument = self._arguments[self._next_arg_i]
+   if argument then
+      self:_open(argument)
+      self:_pass(argument, data)
+   else
+      local command = self.context[data]
+      if command and command.type == "command" then
+         self._result[command.target] = {{}}
+         self:_switch(command)
+      else
+         if #self._commands > 0 then
+            self:_error("unknown command %s", data)
+         else
+            self:_error("too many arguments")
+         end
+      end
+   end
+end
+
+function State:get_result()
+   self:_check()
+
+   local result = {}
+
+   local invocations
+   for _, element in ipairs(self._all_elements) do
+      invocations = self._result[element.target]
+
+      if element.maxcount == 1 then
+         if #invocations > 0 then
+            if element.maxargs == 0 then
+               result[element.target] = true
+            elseif element.maxargs == 1 and element.minargs == 1 then
+               result[element.target] = invocations[1][1]
+            else
+               result[element.target] = invocations[1]
+            end
+         end
+      else
+         if element.maxargs == 0 then
+            result[element.target] = #invocations
+         elseif element.maxargs == 1 and element.minargs == 1 then
+            local new_result = {}
+            for i, passed in ipairs(invocations) do
+               new_result[i] = passed[1]
+            end
+            result[element.target] = new_result
+         else
+            result[element.target] = invocations
+         end
+      end
+   end
+
+   return result
+end
+
+function State:_check()
+   self:_assert(not self._parser.must_command, "a command is required")
+
+   local invocations
+   for _, element in ipairs(self._all_elements) do
+      invocations = self._result[element.target] or {}
+      if #invocations > element.maxcount then
+         if element.no_overwrite then
+            self:_error("option %s can only be used %d times", element.name, element.maxcount)
+         else
+            local new_invocations = {}
+            for i = 1, element.maxcount do
+               new_invocations[i] = invocations[#invocations-element.maxcount+i]
+            end
+            invocations = new_invocations
+         end
+      end
+
+      self:_assert(#invocations >= element.mincount, "option %s must be used at least %d times", element.name, element.mincount)
+
+      for _, passed in ipairs(invocations) do
+         self:_assert(#passed <= element.maxargs, "%s takes at most %d arguments", element.name, element.maxargs)
+         self:_assert(#passed >= element.minargs, "%s takes at least %d arguments", element.name, element.minargs)
+      end
+
+      self._result[element.target] = invocations
+   end
+
+   for _, group in ipairs(self._all_groups) do
+      local invoked
+      for _, element in ipairs(group.elements) do
+         if #self._result[element.target] > 0 then
+            if invoked then
+               self:_error("%s can not be used together with %s", invoked.name, element.name)
+            else
+               invoked = element
+            end
+         end
+      end
+
+      if group.required then
+         self:_assert(invoked, "WIP(required mutually exclusive group)")
+      end
+   end
+end
+
+function State:_open(element)
+   if not self._result[element.target] then
+      self._result[element.target] = {}
+   end
+
+   table.insert(self._result[element.target], {})
+
+   if element.type == "argument" then
+      self._next_arg_i = self._next_arg_i+1
+   end
+
+   self._current = element
+end
+
+function State:_can_pass(element)
+   local invocations = self._result[element.target]
+   local passed = invocations[#invocations]
+
+   return #passed < element.maxargs
+end
+
+function State:_pass(element, data)
+   local invocations = self._result[element.target]
+   local passed = invocations[#invocations]
+
+   table.insert(passed, data)
+end
+
+function State:_switch(command)
+   self._parser = command
+   self._arguments = command.arguments
+   self._commands = command.commands
+
+   for _, element in ipairs(command.elements) do
+      table.insert(self._all_elements, element)
+   end
+
+   for _, group in ipairs(command.groups) do
+      table.insert(self._all_groups, group)
+   end
+
+   self.context = setmetatable(command.context, {__index = self.context})
+   self._next_arg_i = 1
+end
+
+function State:_error(...)
+   return self._parser:error(...)
+end
+
+function State:_assert(...)
+   return self._parser:assert(...)
+end
+
+return State
diff --git a/test/test.lua b/test/test.lua
new file mode 100644
index 0000000..8a754c6
--- /dev/null
+++ b/test/test.lua
@@ -0,0 +1,24 @@
+local largparse = require "largparse"
+local serpent = require "serpent"
+
+local parser = largparse.parser()
+
+parser:argument("input", {
+   args = 2
+})
+
+parser:flag("-q", "--quiet")
+parser:option("-s", "--server")
+
+parser:mutually_exclusive(
+   parser:flag("-q", "--quiet"),
+   parser:option("-s", "--server")
+)
+
+local run = parser:command "run"
+
+run:flag("-f", "--fast")
+
+local args = parser:parse()
+
+print(serpent.block(args))