Module:Parameters

local export = {}

-- A helper function to escape magic characters in a string -- Magic characters: ^$()%.[]*+-? local plain = require("Module:string").pattern_escape

-- A helper function that removes empty numeric indexes in a table, -- so that the values are tightly packed like in a normal Lua table. local remove_holes = require("Module:table").compressSparseArray

function export.process(args, params, return_unknown) local args_new = {}

-- Process parameters for specific properties local required = {} local patterns = {} local list_from_index = nil

for name, param in pairs(params) do if param.required then if param.alias_of then require("Module:debug").track("parameters/required alias") end required[name] = true end

if param.list then local key = name if type(name) == "string" then key = string.gsub(name, "=", "") end if param.default ~= nil then args_new[key] = {param.default, maxindex = 1} else args_new[key] = {maxindex = 0} end

if type(param.list) == "string" then -- If the list property is a string, then it represents the name -- to be used as the prefix for list items. This is for use with lists -- where the first item is a numbered parameter and the -- subsequent ones are named, such as 1, pl2, pl3. if string.find(param.list, "=") then patterns["^" .. string.gsub(plain(param.list), "=", "(%%d+)") .. "$"] = name else patterns["^" .. plain(param.list) .. "(%d+)$"] = name end elseif type(name) == "number" then -- If the name is a number, then all indexed parameters from -- this number onwards go in the list. list_from_index = name else if string.find(name, "=") then patterns["^" .. string.gsub(plain(name), "=", "(%%d+)") .. "$"] = string.gsub(name, "=", "") else patterns["^" .. plain(name) .. "(%d+)$"] = name end end

if string.find(name, "=") then require("Module:debug").track("parameters/name with equals") params[string.gsub(name, "=", "")] = params[name] params[name] = nil end elseif param.default ~= nil then args_new[name] = param.default end end

-- Process the arguments local args_unknown = {}

for name, val in pairs(args) do local index = nil

if type(name) == "number" then if list_from_index ~= nil and name >= list_from_index then index = name - list_from_index + 1 name = list_from_index end else -- Does this argument name match a pattern? for pattern, pname in pairs(patterns) do index = mw.ustring.match(name, pattern)

-- It matches, so store the parameter name and the -- numeric index extracted from the argument name. if index then index = tonumber(index) name = pname break end end end

-- If no index was found, use 1 as the default index. -- This makes list parameters like g, g2, g3 put g at index 1. index = index or 1

local param = params[name]

-- If the argument is not in the list of parameters, trigger an error. -- return_unknown suppresses the error, and stores it in a separate list instead. if not param then if return_unknown then args_unknown[name] = val else error("The parameter \"" .. name .. "\" is not used by this template.", 2) end else -- Remove leading and trailing whitespace unless allow_whitespace is true. if not param.allow_whitespace then val = mw.text.trim(val) end

-- Empty string is equivalent to nil unless allow_empty is true. if val == "" and not param.allow_empty then val = nil end

-- Convert to proper type if necessary. if param.type == "boolean" then val = not (not val or val == "" or val == "0" or val == "no" or val == "n" or val == "false") elseif param.type == "number" and val ~= nil then val = tonumber(val) end

-- Can't use "if val" alone, because val may be a boolean false. if val ~= nil then -- Mark it as no longer required, as it is present. required[param.alias_of or name] = nil

-- Store the argument value. if param.list then -- If the parameter is an alias of another, store it as the original, -- but avoid overwriting it; the original takes precedence. if not param.alias_of then args_new[name][index] = val

-- Store the highest index we find. args_new[name].maxindex = math.max(index, args_new[name].maxindex) elseif args[param.alias_of] == nil then if params[param.alias_of] and params[param.alias_of].list then args_new[param.alias_of][index] = val

-- Store the highest index we find. args_new[param.alias_of].maxindex = math.max(1, args_new[param.alias_of].maxindex) else args_new[param.alias_of] = val end end else -- If the parameter is an alias of another, store it as the original, -- but avoid overwriting it; the original takes precedence. if not param.alias_of then args_new[name] = val elseif args[param.alias_of] == nil then if params[param.alias_of] and params[param.alias_of].list then args_new[param.alias_of][1] = val

-- Store the highest index we find. args_new[param.alias_of].maxindex = math.max(1, args_new[param.alias_of].maxindex) else args_new[param.alias_of] = val end end end end end end

-- The required table should now be empty. -- If any entry remains, trigger an error, unless we're in the template namespace. if mw.title.getCurrentTitle().nsText ~= "Template" then local list = {} for name, param in pairs(required) do table.insert(list, name) end

local count = #list if count == 1 then error('The parameter "' .. list[1] .. '" is required.', 2) elseif count == 2 then error('The parameters "' .. table.concat(list, '" and "') .. '" are required.', 2) elseif count > 2 then error('The parameters "' .. mw.text.listToText(list, '", "', '", and "') .. '" are required.', 2) end end

-- Remove holes in any list parameters if needed. for name, val in pairs(args_new) do if type(val) == "table" and not params[name].allow_holes then args_new[name] = remove_holes(val) end end

if return_unknown then return args_new, args_unknown else return args_new end end

return export