Module:Japanese calendar

-- This module defines an "era" class for processing eras in the Japanese calendar. -- It also contains functions to export the class properties to #invoke.

local eras = mw.loadData( 'Module:Japanese calendar/data' ) local halfToFull = require( 'Module:Convert character width' ).full -- Converts half-width characters to full-width characters.

-- Helper functions

local function yearToEraIndex( year ) year = tonumber( year ) if type( year ) ~= 'number' then return end for i, t in ipairs( eras ) do       if year > t.startYear then return i       elseif year == t.startYear then if eras[ i + 1 ] and eras[ i + 1 ].startYear == t.startYear then -- This checks for occasions when there were more than two eras in the same year. At the moment, that only applies to the year 686. return i + 1 else return i           end end end end

local function textToEraIndex( s ) if not s or s == '' then return end for i, t in ipairs( eras ) do       if s == t.article or s == t.kanji then return i       end end end

-- Era class definition

local era = {} era.__index = era

function era:new( init ) init = type( init ) == 'table' and init or {} local obj = {} -- Grab the data from the init table. obj.gregorianYear = tonumber( init.year ) local initText = type( init.era ) == 'string' and init.era or nil local initIndex = tonumber( init.index ) if not ( initIndex and initIndex >= 1 and math.floor( initIndex ) == initIndex and initIndex ~= math.huge ) then -- Check that initIndex is a positive integer. initIndex = nil end -- Calculate the era data from the input. First we find the era from the era index, although this is only supposed -- to be for internal use. Next we find the era from the era name or the kanji if possible, as this allows us to   -- specify the last year of one era rather than the first year of the next one, if that is the desired behaviour. local eraIndex if initIndex then eraIndex = initIndex elseif initText then eraIndex = textToEraIndex( initText ) elseif obj.gregorianYear then eraIndex = yearToEraIndex( obj.gregorianYear ) end -- If the data entry was found for the era, process it and add it to the object. if not eraIndex then return end local eraData = eras[ eraIndex ] if not eraData or not eraData.article or eraData.article == '' then return end -- Exit if we are not dealing with a valid era. obj.startYear = eraData.startYear obj.endYear = eraData.endYear obj.article = eraData.article obj.kanji = eraData.kanji obj.label = eraData.label -- Create a link to the era article if possible. if obj.label and obj.article then obj.link = mw.ustring.format( '%s', obj.article, obj.label ) elseif obj.article then obj.link = mw.ustring.format( '%s', obj.article ) end -- Allow matching years to different eras, but only for the first year of the next era. For example, Taisho 15 is also Showa 1, but there is no such thing as Taisho 16. -- So, the code era:new{ year = 1926, era = "Taishō" } will return an object with an eraYear of 15, and era:new{ year = 1926 } will return an object with an eraYear of 1. local nextEraData = eras[ eraIndex - 1 ] local nextStartYear = nextEraData and nextEraData.startYear if obj.gregorianYear and ( -- If there is a later era, only allow the first year of that era or an earlier year.           not nextStartYear            or ( nextStartYear and obj.gregorianYear <= nextStartYear )        ) and obj.gregorianYear >= obj.startYear -- Don't allow negative years. and obj.article ~= '' -- Don't allow periods between named eras. and ( obj.endYear and obj.gregorianYear <= obj.endYear or true ) -- If this era has an end year, don't allow years that are greater than the end year. then obj.eraYear = obj.gregorianYear - obj.startYear + 1 if obj.eraYear == 1 then obj.eraYearKanji = '元' else obj.eraYearKanji = halfToFull( obj.eraYear ) end end

-- Make sure obj.label is available even if it is the same as the article name. obj.label = obj.label or obj.article -- Add methods to get the next and previous eras. function obj:getNextEra if not eraIndex then return end return era:new{ index = eraIndex - 1, year = obj.gregorianYear } end function obj:getPreviousEra if not eraIndex then return end return era:new{ index = eraIndex + 1, year = obj.gregorianYear } end

-- Gets the era object for the "old" era. In most cases this is the same as the current era object, but -- if the era year for the current object is 1, this method will return the era object for the previous -- era. If the method can't find a valid previous era it will return the object for the current era. function obj:getOldEra if obj.eraYear == 1 then local prevEra = obj:getPreviousEra if prevEra then return prevEra else return obj end else return obj end end return setmetatable( obj, {       __index = self    }) end

-- Interface for old Japanese calendar templates

local function getStartYear( obj ) return obj.startYear end

local function getEndYear( obj ) return obj.endYear end

local function getEraYear( obj ) return obj.eraYear end

local function getEraYearKanji( obj ) return obj.eraYearKanji end

local function getArticle( obj ) return obj.article end

local function getLabel( obj ) return obj.label end

local function getLink( obj ) return obj.link end

local function getKanji( obj ) return obj.kanji end

local function getLabelAndEraYear( obj, kanji ) local eraYear = kanji and obj.eraYearKanji or obj.eraYear if obj.label and eraYear then return mw.ustring.format( '%s %s', obj.label, tostring( eraYear ) ) end end

local function getLinkAndEraYear( obj, kanji ) local eraYear = kanji and obj.eraYearKanji or obj.eraYear if obj.link and eraYear then return mw.ustring.format( '%s %s', obj.link, tostring( eraYear ) ) end end

local function getLabelAndEraYearKanji( obj ) return getLabelAndEraYear( obj, true ) end

local function getLinkAndEraYearKanji( obj ) return getLinkAndEraYear( obj, true ) end

-- Process the arguments from #invoke. local function makeWrapper( func ) return function( frame ) -- If called via #invoke, use the args passed into the invoking -- template, or the args passed to #invoke if any exist. Otherwise -- assume args are being passed directly in from the debug console -- or from another Lua module. local origArgs if frame == mw.getCurrentFrame then origArgs = frame:getParent.args for k, v in pairs( frame.args ) do               origArgs = frame.args break end else origArgs = frame end -- Trim whitespace and remove blank arguments. local args = {} for k, v in pairs( origArgs ) do           if type( v ) == 'string' then v = mw.text.trim( v ) end if v ~= '' then args[k] = v           end end local myEra local otherEraArgs = {} table.insert( otherEraArgs, args.next ) table.insert( otherEraArgs, args.previous ) table.insert( otherEraArgs, args.old ) if #otherEraArgs > 1 then return ' Module:Japanese calendar error: you can only specify one parameter out of "next", "previous" and "old". '       elseif args.next then myEra = era:new( args ):getNextEra elseif args.previous then myEra = era:new( args ):getPreviousEra elseif args.old then myEra = era:new( args ):getOldEra else myEra = era:new( args ) end return myEra and func( myEra ) or '' end end

-- Return the era class and the template interface

return { era = function return era end, -- Accessor function for getting the era class from other modules. baseyear = makeWrapper( getStartYear ), endyear = makeWrapper( getEndYear ), year = makeWrapper( getEraYear ), kanjiyear = makeWrapper( getEraYearKanji ), article = makeWrapper( getArticle ), label = makeWrapper( getLabel ), link = makeWrapper( getLink ), kanji = makeWrapper( getKanji ), label_year = makeWrapper( getLabelAndEraYear ), link_year = makeWrapper( getLinkAndEraYear ), label_kanjiyear = makeWrapper( getLabelAndEraYearKanji ), link_kanjiyear = makeWrapper( getLinkAndEraYearKanji ) }