local inspect ={
	_VERSION = 'inspect.lua 3.1.0',
	_URL     = 'http://github.com/kikito/inspect.lua',
	_DESCRIPTION = 'human-readable representations of tables',
	_LICENSE = [[
	  MIT LICENSE

	  Copyright (c) 2013 Enrique García Cota

	  Permission is hereby granted, free of charge, to any person obtaining a
	  copy of this software and associated documentation files (the
	  "Software"), to deal in the Software without restriction, including
	  without limitation the rights to use, copy, modify, merge, publish,
	  distribute, sublicense, and/or sell copies of the Software, and to
	  permit persons to whom the Software is furnished to do so, subject to
	  the following conditions:

	  The above copyright notice and this permission notice shall be included
	  in all copies or substantial portions of the Software.

	  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
	  OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
	  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
	  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
	  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
	  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
	  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
	]]
  }

  local tostring = tostring

  inspect.KEY       = setmetatable({}, {__tostring = function() return 'inspect.KEY' end})
  inspect.METATABLE = setmetatable({}, {__tostring = function() return 'inspect.METATABLE' end})

  local function rawpairs(t)
	return next, t, nil
  end

  -- Apostrophizes the string if it has quotes, but not aphostrophes
  -- Otherwise, it returns a regular quoted string
  local function smartQuote(str)
	if str:match('"') and not str:match("'") then
	  return "'" .. str .. "'"
	end
	return '"' .. str:gsub('"', '\\"') .. '"'
  end

  -- \a => '\\a', \0 => '\\0', 31 => '\31'
  local shortControlCharEscapes = {
	["\a"] = "\\a",  ["\b"] = "\\b", ["\f"] = "\\f", ["\n"] = "\\n",
	["\r"] = "\\r",  ["\t"] = "\\t", ["\v"] = "\\v"
  }
  local longControlCharEscapes = {} -- \a => nil, \0 => \000, 31 => \031
  for i=0, 31 do
	local ch = string.char(i)
	if not shortControlCharEscapes[ch] then
	  shortControlCharEscapes[ch] = "\\"..i
	  longControlCharEscapes[ch]  = string.format("\\%03d", i)
	end
  end

  local function escape(str)
	return (str:gsub("\\", "\\\\")
			   :gsub("(%c)%f[0-9]", longControlCharEscapes)
			   :gsub("%c", shortControlCharEscapes))
  end

  local function isIdentifier(str)
	return type(str) == 'string' and str:match( "^[_%a][_%a%d]*$" )
  end

  local function isSequenceKey(k, sequenceLength)
	return type(k) == 'number'
	   and 1 <= k
	   and k <= sequenceLength
	   and math.floor(k) == k
  end

  local defaultTypeOrders = {
	['number']   = 1, ['boolean']  = 2, ['string'] = 3, ['table'] = 4,
	['function'] = 5, ['userdata'] = 6, ['thread'] = 7
  }

  local function sortKeys(a, b)
	local ta, tb = type(a), type(b)

	-- strings and numbers are sorted numerically/alphabetically
	if ta == tb and (ta == 'string' or ta == 'number') then return a < b end

	local dta, dtb = defaultTypeOrders[ta], defaultTypeOrders[tb]
	-- Two default types are compared according to the defaultTypeOrders table
	if dta and dtb then return defaultTypeOrders[ta] < defaultTypeOrders[tb]
	elseif dta     then return true  -- default types before custom ones
	elseif dtb     then return false -- custom types after default ones
	end

	-- custom types are sorted out alphabetically
	return ta < tb
  end

  -- For implementation reasons, the behavior of rawlen & # is "undefined" when
  -- tables aren't pure sequences. So we implement our own # operator.
  local function getSequenceLength(t)
	local len = 1
	local v = rawget(t,len)
	while v ~= nil do
	  len = len + 1
	  v = rawget(t,len)
	end
	return len - 1
  end

  local function getNonSequentialKeys(t)
	local keys, keysLength = {}, 0
	local sequenceLength = getSequenceLength(t)
	for k,_ in rawpairs(t) do
	  if not isSequenceKey(k, sequenceLength) then
		keysLength = keysLength + 1
		keys[keysLength] = k
	  end
	end
	table.sort(keys, sortKeys)
	return keys, keysLength, sequenceLength
  end

  local function countTableAppearances(t, tableAppearances)
	tableAppearances = tableAppearances or {}

	if type(t) == 'table' then
	  if not tableAppearances[t] then
		tableAppearances[t] = 1
		for k,v in rawpairs(t) do
		  countTableAppearances(k, tableAppearances)
		  countTableAppearances(v, tableAppearances)
		end
		countTableAppearances(getmetatable(t), tableAppearances)
	  else
		tableAppearances[t] = tableAppearances[t] + 1
	  end
	end

	return tableAppearances
  end

  local copySequence = function(s)
	local copy, len = {}, #s
	for i=1, len do copy[i] = s[i] end
	return copy, len
  end

  local function makePath(path, ...)
	local keys = {...}
	local newPath, len = copySequence(path)
	for i=1, #keys do
	  newPath[len + i] = keys[i]
	end
	return newPath
  end

  local function processRecursive(process, item, path, visited)
	if item == nil then return nil end
	if visited[item] then return visited[item] end

	local processed = process(item, path)
	if type(processed) == 'table' then
	  local processedCopy = {}
	  visited[item] = processedCopy
	  local processedKey

	  for k,v in rawpairs(processed) do
		processedKey = processRecursive(process, k, makePath(path, k, inspect.KEY), visited)
		if processedKey ~= nil then
		  processedCopy[processedKey] = processRecursive(process, v, makePath(path, processedKey), visited)
		end
	  end

	  local mt  = processRecursive(process, getmetatable(processed), makePath(path, inspect.METATABLE), visited)
	  if type(mt) ~= 'table' then mt = nil end -- ignore not nil/table __metatable field
	  setmetatable(processedCopy, mt)
	  processed = processedCopy
	end
	return processed
  end



  -------------------------------------------------------------------

  local Inspector = {}
  local Inspector_mt = {__index = Inspector}

  function Inspector:puts(...)
	local args   = {...}
	local buffer = self.buffer
	local len    = #buffer
	for i=1, #args do
	  len = len + 1
	  buffer[len] = args[i]
	end
  end

  function Inspector:down(f)
	self.level = self.level + 1
	f()
	self.level = self.level - 1
  end

  function Inspector:tabify()
	self:puts(self.newline, string.rep(self.indent, self.level))
  end

  function Inspector:alreadyVisited(v)
	return self.ids[v] ~= nil
  end

  function Inspector:getId(v)
	local id = self.ids[v]
	if not id then
	  local tv = type(v)
	  id              = (self.maxIds[tv] or 0) + 1
	  self.maxIds[tv] = id
	  self.ids[v]     = id
	end
	return tostring(id)
  end

  function Inspector:putKey(k)
	if isIdentifier(k) then return self:puts(k) end
	self:puts("[")
	self:putValue(k)
	self:puts("]")
  end

  function Inspector:putTable(t)
	if t == inspect.KEY or t == inspect.METATABLE then
	  self:puts(tostring(t))
	elseif self:alreadyVisited(t) then
	  self:puts('<table ', self:getId(t), '>')
	elseif self.level >= self.depth then
	  self:puts('{...}')
	else
	  if self.tableAppearances[t] > 1 then self:puts('<', self:getId(t), '>') end

	  local nonSequentialKeys, nonSequentialKeysLength, sequenceLength = getNonSequentialKeys(t)
	  local mt                = getmetatable(t)

	  self:puts('{')
	  self:down(function()
		local count = 0
		for i=1, sequenceLength do
		  if count > 0 then self:puts(',') end
		  self:puts(' ')
		  self:putValue(t[i])
		  count = count + 1
		end

		for i=1, nonSequentialKeysLength do
		  local k = nonSequentialKeys[i]
		  if count > 0 then self:puts(',') end
		  self:tabify()
		  self:putKey(k)
		  self:puts(' = ')
		  self:putValue(t[k])
		  count = count + 1
		end

		if type(mt) == 'table' then
		  if count > 0 then self:puts(',') end
		  self:tabify()
		  self:puts('<metatable> = ')
		  self:putValue(mt)
		end
	  end)

	  if nonSequentialKeysLength > 0 or type(mt) == 'table' then -- result is multi-lined. Justify closing }
		self:tabify()
	  elseif sequenceLength > 0 then -- array tables have one extra space before closing }
		self:puts(' ')
	  end

	  self:puts('}')
	end
  end

  function Inspector:putValue(v)
	local tv = type(v)

	if tv == 'string' then
	  self:puts(smartQuote(escape(v)))
	elseif tv == 'number' or tv == 'boolean' or tv == 'nil' or
		   tv == 'cdata' or tv == 'ctype' then
	  self:puts(tostring(v))
	elseif tv == 'table' then
	  self:putTable(v)
	else
	  self:puts('<', tv, ' ', self:getId(v), '>')
	end
  end

  -------------------------------------------------------------------

  function inspect.inspect(root, options)
	options       = options or {}

	local depth   = options.depth   or math.huge
	local newline = options.newline or '\n'
	local indent  = options.indent  or '  '
	local process = options.process

	if process then
	  root = processRecursive(process, root, {}, {})
	end

	local inspector = setmetatable({
	  depth            = depth,
	  level            = 0,
	  buffer           = {},
	  ids              = {},
	  maxIds           = {},
	  newline          = newline,
	  indent           = indent,
	  tableAppearances = countTableAppearances(root)
	}, Inspector_mt)

	inspector:putValue(root)

	return table.concat(inspector.buffer)
  end

  setmetatable(inspect, { __call = function(_, ...) return inspect.inspect(...) end })

  return inspect
