-- This module produces a count of all the arguments passed to it.  local yesno = require('Module:Yesno')  -- Trim a string local function trim(s)  return s:match('^%s*(.-)%s*$') end  -- Test whether a string is blank local function isBlank(s)  return not s:find('%S') end  -- Tests whether a string is a valid positional key, and if so, returns it. If -- the key is invalid, this returns nil. local function isPositionalKey(s)  s = trim(s)  if s:find('^[1-9][0-9]*$') then  return tonumber(s)  end end  -- Return the count of all arguments for which testFunc returns a truthy value. local function count(args, testFunc)  local ret = 0  for key, val in pairs(args) do  if testFunc(key, val) then  ret = ret + 1  end  end  return ret end  -- Check shared arguments and get the parent argument count. local function main(frame, testFunc)  local blankifiedTestFunc  if yesno(frame.args.checkblanks) ~= false then  -- Extend the test function to check for blanks as well.  blankifiedTestFunc = function (key, val)  if not isBlank(val) then  return testFunc(key, val)  end  end  else  blankifiedTestFunc = testFunc  end  return count(frame:getParent().args, blankifiedTestFunc) end  return {  -- Called with {{#invoke:ParameterCount|all}}  -- All specified parameters are counted, even those not supported by the  -- template.  all = function (frame)  return main(frame, function () return true end)  end,   -- Called with {{#invoke:ParameterCount|main}}  -- Users can specify a list of parameters to check, and a list of Lua  -- Ustring patterns to check each parameter against.  main = function (frame)  local args = frame.args  local keys, patterns = {}, {}   -- Get key list  for i, key in ipairs(args) do  local positionalKey = isPositionalKey(key)  if positionalKey then  keys[positionalKey] = true  else  keys[trim(key)] = true  end  end   -- Get patterns  do  local function getPattern(i)  local pattern = args['pattern' .. tostring(i)]  if pattern and pattern ~= '' then  return pattern  end  end  local i = 1  local pattern = getPattern(i)  while pattern do  patterns[i] = pattern  i = i + 1  pattern = getPattern(i)  end  end   -- Construct the test function  local testFunc = function (key, val)  if keys[key] then  return true  end  for i, pattern in ipairs(patterns) do  if mw.ustring.find(tostring(key), pattern) then  return true  end  end  return false  end   return main(frame, testFunc)  end }