parametercount

-- 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 }