Module:Engvar

-- This module implements Template:Engvar.
-- Template:Engvar is to be build into the template (like an infobox), with default & variant spellings defined.
-- That template should also allow parameter '|engvar=' for the editor (article page).
-- The module/template Engvar then returns the spelling variant as is set in that article (for example '|engvar=en-GB').
-- The defaultWord is returned, unless the engvar input hits on a defined (en-XX) variant word.
local p = {}
local getArgs = require('Module:Arguments').getArgs
local gsub = string.gsub
local lower = string.lower
local upper = string.upper

function p.variants(frame)
local args = getArgs(frame)
 return p._variants(args)
end

function p._variants(args)
local returnWord = nil

 local defaultWord = args.defaultWord or ''
 if args.engvar == nil then
  -- Nothing to look for; use defaultWord right away
  returnWord = defaultWord
 elseif args.defaultLang == gsub(lower(args.engvar), '^en%-(%w%w)$', formatISO) then
  -- By the defaultLang, the defaultWord is asked
  returnWord = defaultWord
 else
  returnWord = args[gsub(lower(args.engvar), '^en%-(%w%w)$', formatISO)]
 end

 if returnWord == nil then
  -- No hit so far. Search by words in the engvar entered, checking the list
  local useLang = engvarLang(args.engvar)
  if useLang == nil then
   returnWord = defaultWord .. addMaintCat(args)
  else
   returnWord = args[useLang] or defaultWord
  end
 end

 return returnWord
end

-- Returns arguments and intermediate result. Plus the template result, in front.
function p.explain(frame)
local args = getArgs(frame)
local ret = {}
 table.insert(ret, '\n\n: Settings:')
 table.insert(ret, 'defaultWord=' .. (args.defaultWord or '') .. '; ')
 table.insert(ret, 'defaultLang=' .. (args.defaultLang or '') .. '; ')
 table.insert(ret, 'engvarCat=' .. (args.engvarCat or '[default:yes]') .. '; ')
 table.insert(ret, 'engvarCatSort=' .. (args.engvarCatSort or ''))
 table.insert(ret, '\n\n: engvar=' .. (args.engvar or '') .. ' [input] ')
 local useLang = engvarLang(args.engvar or '')
 table.insert(ret, ' => Engvar code [used]: >' .. (useLang or '') .. '<.')
 
 for k, v in pairs(args) do
  if k == 'en-UK' then
   table.insert(ret, k .. ' ? better: use "en-GB"; ')
  elseif k == 'en-SA' then
   table.insert(ret, k .. ' ? misleading; use "en-ZA"; ')
  end
  
  if k == 'defaultWord' then
  elseif k == 'defaultLang' then
  elseif k == 'engvar' then
  elseif k == 'engvarcat' then
  elseif k == gsub(lower(k), '^en%-(%w%w)$', formatISO) then
   table.insert(ret, k .. '=' .. v .. '; ')
  else
   table.insert(ret, k .. ' [not standard:]=' .. v .. '; ')
  end

 end
 return (args.engvar or '') .. ' => ' .. p._variants(args) .. table.concat(ret, ' ')
end

-- Turn a match into pattern 'en-XX'
function formatISO(country)
 return ('en-' .. upper(country) or '')
end

function engvarLang(searchEngvar)
-- Search verbose language identifiers to ISO-format 'en-XX'
-- Assumed: not a blank string '' to search
local match = string.match

 searchEngvar = gsub(searchEngvar, '^%s*en%-(.*)', '%1') -- rm any opening 'en-'.
 searchEngvar = gsub(lower(searchEngvar), '[%s%(%)%-]', '') -- To lc, remove all: (, ) , ws, hyphen.
 local useLang
 --Special codes
 if match(searchEngvar, 'oxford')
  or searchEngvar == 'oed' then
   useLang = 'en-OED' -- 'oxford' to catch before anyting 'british'
 elseif match(searchEngvar, 'iupac') then
   useLang = 'en-IUPAC' -- chemistry
 -- Very often used
 elseif match(searchEngvar, 'british')
  or searchEngvar == 'uk'
  or searchEngvar == 'gbr' then
   useLang = 'en-GB'
 elseif searchEngvar == 'us'
  or match(searchEngvar, 'unitedstates')
  or searchEngvar == 'american'
  or searchEngvar == 'usa' then
   useLang = 'en-US'
 elseif match(searchEngvar, 'australia')
  or searchEngvar == 'aus' then
   useLang = 'en-AU'
 -- Often used
 elseif match(searchEngvar, 'india')
  or searchEngvar == 'ind' then
   useLang = 'en-IN'
 elseif searchEngvar == 'newzealand'
  or searchEngvar == 'nzl' then
   useLang = 'en-NZ'
 elseif match(searchEngvar, 'southafrica') -- not: en-SA
  or searchEngvar == 'zaf' then
   useLang = 'en-ZA'
 elseif searchEngvar == 'canada'
  or searchEngvar == 'can' then
   useLang = 'en-CA'
 elseif match(searchEngvar, 'hiberno')
  or match(searchEngvar, 'ireland')
  or match(searchEngvar, 'irish')
  or searchEngvar == 'irl' then
   useLang = 'en-EI'
 elseif match(searchEngvar, 'hongkong')
  or searchEngvar == 'hkg' then
   useLang = 'en-HK'
 -- Less often used
 elseif match(searchEngvar, 'jamaica')
  or searchEngvar == 'jam' then
   useLang = 'en-JM'
 elseif match(searchEngvar, 'malawi')
  or searchEngvar == 'mwi' then
   useLang = 'en-MW'
 elseif match(searchEngvar, 'nigeria')
  or searchEngvar == 'nga' then
   useLang = 'en-NG'
 elseif match(searchEngvar, 'pakistan')
  or searchEngvar == 'pak' then
   useLang = 'en-PK'
 elseif match(searchEngvar, 'philippine')
  or searchEngvar == 'phl' then
   useLang = 'en-PH'
 elseif match(searchEngvar, 'scotland')
  or match(searchEngvar, 'scottish')
  or searchEngvar == 'sco' then
   useLang = 'en-SCO' -- Has no alpha-2 code; not 'scotch'
 elseif match(searchEngvar, 'singapore')
  or searchEngvar == 'sgp' then
   useLang = 'en-SG'
 elseif match(searchEngvar, 'trinidad')
  or match(searchEngvar, 'tobago')
  or searchEngvar == 'tto' then
   useLang = 'en-TT'
 else
  useLang = nil
 end
 
 return useLang
end

function addMaintCat(args)
local catMaintenance
 if args.engvarCat == 'no' then
 else
  local title = mw.title.getCurrentTitle()
  if title:inNamespaces(0) then  -- 0=main, 10=templ, 828=module
   if args.engvarCatSort then
    catMaintenance = '|' .. args.engvarCatSort .. ', ' .. title.text
   end
   catMaintenance = '[[Category:Articles using an unknown Template:Engvar option' .. (catMaintenance or '') .. ']]'
  end
 end
 return catMaintenance or ''
end

return p