Module:Road data/parser

local p = {} -- Package to be exported-- Change to "" upon deployment.local moduleSuffix = ""local parserHooksModuleName = "Module:Road data/parser/hooks" .. moduleSuffix-- Local library aliaseslocal format = string.formatlocal gsub = mw.ustring.gsublocal upper = mw.ustring.upper----- Substitution pattern based on passed arguments-- Syntax: [param|value|match|mismatch]-- where--  param is the parameter name to be tested--  value is the value to test against argument; if empty, the argument is--    tested for existence--  match is the string to be substituted if the argument matches value--  mismatch is the string to be substituted if the argument does not match--    the value-- These arguments may not contain "[", "|", or "]".local prepattern = "%[(%w+)%|([^%[|%]]*)%|([^%[|%]]*)%|([^%[|%]]*)%]"----- Parameter substitution pattern-- Syntax: %param%-- where param is the name of the parameter whose value is to be substituted-- in place of %param%.local pattern = "%%(%w+)%%"----- Perform substitutions.-- @param #string formatStr The string the be substituted-- @param #table args The arguments passed to this modulelocal function subst(formatStr, args)----- Perform a substitution based on passed argument.-- @param #string param The parameter name to be tested-- @param #string value The value to test against argument; if empty,-- the argument is tested for existence-- @param #string ifmatch The resulting string if the argument matches-- `value`-- @param #string ifmismatch The resulting string if the argument does not-- match `value`-- @return #string either `ifmatch` or `ifmismatch`, based on the testlocal function testArgs(param, value, ifmatch, ifmismatch)local arg = args[param] or ''if value ~= '' thenreturn arg == value and ifmatch or ifmismatchelsereturn arg ~= '' and ifmatch or ifmismatchendend-- argument-test substitutionslocal preprocessed = gsub(formatStr, prepattern, testArgs)-- parameter substitutionsreturn (gsub(preprocessed, pattern, args))-- gsub returns number of matches as second value.-- The enclosing parens discards it.end----- Determine whether a given title exists on Wikipedia.-- @param #string name The title, e.g., article name and file name,-- without namespace prefix-- @param #string key The name of the entry being translated.-- @return #boolean `true` if the title exists, false otherwiselocal function titleExists(name, key)if name == '' then return false endlocal namespaceModule = mw.loadData('Module:Road data/parser/namespace')-- Retrieve the namespace for `key`.local namespace = namespaceModule[key] or 0local title = mw.title.new(name, namespace);return title.existsend----- Determine whether titles exist on Wikipedia.-- @param value A string or a table containing strings of titles to be checked-- against-- @param #string key The name of the entry being translated.-- @return #boolean `true` if all titles exist, false otherwiselocal function ifexists(value, key)local valueType = type(value)if valueType == "table" then-- If `value` is a table, recursively check the existence-- for each element within the table.for _,entry in pairs(value) doif not ifexists(entry, key) then return false endendreturn trueend-- Otherwise, `value` is a string, so check the existence for that string.return titleExists(value, key)end----- Perform a translation on a given entry.-- @param entry An entry to be translated; may be any non-function type.-- A table may be a parser hook specification, a switch table, or an-- ordinary value table.  Translations are applied recursively.-- @param #table args The arguments passed to this module-- @param #string key The name of the entry being translated.-- @return The translated entrylocal function translate(entry, args, key)if type(entry) == "string" thenreturn subst(entry, args) -- Substitute arguments as necessary.elseif type(entry) ~= "table" thenreturn entryelseif entry.hook then-- This entry is a parser hook.-- Requires: Parser hook must have hook field.local hook = entry.hooklocal parserHooksModule = require(parserHooksModuleName)local hookFunction = parserHooksModule[hook]or error("Hook '" .. hook .. "' does not exist", 0)return translate(hookFunction(entry, args), args, key)elseif entry.arg or entry.undefined or entry.default then-- This entry is a switch table.-- Requires: Switch table must have--           arg, undefined, or default fields--           but not hook field.local arg = args[entry.arg or "route"]if entry[arg] then return translate(entry[arg], args, key) endif arg == nil and entry.undefined ~= nil then-- result for unspecified argumentreturn translate(entry.undefined, args, key)end-- default result for mismatchlocal defaultValue = translate(entry.default, args, key)if defaultValue and entry.ifexists then-- Check existence.if ifexists(defaultValue, key) then return defaultValue end-- Failed existence check results in fallback value (default to nil).return entry.otherwise and translate(entry.otherwise, args, key) or nilelsereturn defaultValueendelse-- This entry is a value table.-- Process each table element.local result = {}for key,elem in pairs(entry) doresult[key] = translate(elem, args, key)endreturn resultendend----- Retrieve an entry from a data module based on a given type and key.-- @param #string module The name of the data module to be fetched-- @param type The key for the type table within the loaded table-- @param key The key for the entry within the type table-- @return fetchedTable[type][key] if specified, where `fetchedTable` is the-- table fetched from `module`, nil otherwiselocal function getTypeData(module, type, key)-- Attempt to fetch the given data module.local success, moduleData = pcall(mw.loadData, module)if not success then return false, moduleData end -- Module could not be loaded-- The type table defaults to empty-key table if undefined.local typeTable = moduleData[type] or moduleData['']-- Fallback table is the empty-key table, with the empty table as default.local defaultTable = moduleData[''] or {}if typeTable thenlocal alias = typeTable.aliasif alias and alias.module and alias.type then-- The type table is an alias table.-- Recursively fetch the aliased type data.local aliasedModule = "Module:Road data/strings/" .. alias.modulelocal aliasedType = alias.typereturn getTypeData(aliasedModule, aliasedType, key)endreturn true, typeTable[key] or defaultTable[key] or nilelsereturn true, nilendend----- Determine the module name for the lookup by country and state.-- @param #table args The arguments passed to this module-- @return #string The module name to be fetchedlocal function getModuleName(args)-- countries with submodules for states or provinceslocal stateCountries = {USA = true, CAN = true}local state = upper(args.state or args.province or '')local countryif args.country thencountry = upper(args.country)else-- Recover the country from the given state or province.local countryModule = mw.loadData("Module:Road data/countrymask")country = countryModule[state] or 'UNK'endif stateCountries[country] and state ~= '' then-- Submodule within the country exists.return format("Module:Road data/strings/%s/%s", country, state)endreturn format("Module:Road data/strings/%s", country)end----- Fetch the entry from the appropriate module, and return that entry-- substituted with appropriate values.-- @param #table args The arguments to be used for lookup and substitutions-- @param #string key The key for the entry within the type table-- @param #string type (optional) The key for the type table within the fetched-- module; defaults to args.type-- @param #string moduleName (optional) The name of the module to be fetched;-- defaults to the module determined by country and state-- @return The substituted entryfunction p.parser(args, key, type, moduleName)-- Determine module name, if not given.local dataModuleName = moduleName or getModuleName(args)-- Fetch the entry from the module.local success, formatStr = getTypeData(dataModuleName, type or args.type, key)if not success then return false, formatStr end-- Translate the entry.return translate(formatStr, args, key)endreturn p