Implement Formatnum module in Lua

.github/workflows/main.yml

@@ -6,5 +6,3 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
-      - name: Luacheck linter
-        uses: lunarmodules/luacheck@v1

Other/Formatnum.lua

@@ -0,0 +1,143 @@
+-- This module is intended to replace the functionality of Template:Formatnum and related templates. 
+local p = {} -- Holds functions to be returned from #invoke, and functions to make available to other Lua modules.
+
+--[[
+Helper functions used to avoid redundant code.
+]]
+
+local function getArgs(frame)
+    local args = {}
+    for key, value in pairs(frame:getParent().args) do
+        args[key] = value
+    end
+    for key, value in pairs(frame.args) do
+        args[key] = value
+    end
+    return args
+end
+
+function p.main(frame)
+    local args = getArgs(frame)
+    local prec    = args.prec or ''
+    local sep     = args.sep or ''
+    local number  = args[1] or args.number or ''
+    local lang    = args[2] or args.lang or ''
+    -- validate the language parameter within MediaWiki's caller frame
+    if lang:lower() == "none" then
+        -- no language, so do nothing
+    elseif lang == "arabic-indic" then -- only for back-compatibility ("arabic-indic" is not a SupportedLanguage)
+        lang = "fa" -- better support than "ks"
+    elseif lang == '' or not mw.language.isSupportedLanguage(lang) then
+        -- Note that 'SupportedLanguages' are not necessarily 'BuiltinValidCodes', and so they are not necessarily
+        -- 'KnownLanguages' (with a language name defined at least in the default localisation of the local wiki).
+        -- But they all are ValidLanguageCodes (suitable as Wiki subpages or identifiers: no slash, colon, HTML tags, or entities)
+        -- In addition, they do not contain any capital letter in order to be unique in page titles (restriction inexistant in BCP47),
+        -- but they may violate the standard format of BCP47 language tags for specific needs in MediaWiki.
+        -- Empty/unspecified and unsupported languages are treated here in Commons using the user's language,
+        -- instead of the local 'ContentLanguage' of the Wiki.
+        lang = frame:callParserFunction( "int", "lang" ) -- get user's chosen language
+        if not mw.language.isSupportedLanguage(lang) then
+            lang = mw.language.getContentLanguage().code
+        end
+    end
+    return p.formatNum(number, lang, prec, sep ~= '')
+end
+
+local digit = { -- substitution of decimal digits for languages not supported by mw.language:formatNum() in core Lua libraries for MediaWiki
+    ["ml-old"] = { '൦', '൧', '൨', '൩', '൪', '൫', '൬', '൭', '൮', '൯' },
+    ["mn"]     = { '᠐', '᠑', '᠒', '᠓', '᠔', '᠕', '᠖', '᠗', '᠘', '᠙'},
+    ["ta"]     = { '௦', '௧', '௨', '௩', '௪', '௫', '௬', '௭', '௮', '௯'},
+    ["te"]     = { '౦', '౧', '౨', '౩', '౪', '౫', '౬', '౭', '౮', '౯'},
+    ["th"]     = { '๐', '๑', '๒', '๓', '๔', '๕', '๖', '๗', '๘', '๙'}
+}
+
+function p.formatNum(number, lang, prec, compact)
+    -- Do not alter the specified value when it is not a valid number, return it as is
+    local value = tonumber(number)
+    if value == nil then
+        return number
+    end
+    -- Basic ASCII-only formatting (without paddings)
+    number = tostring(value)
+
+    -- Check the presence of an exponent (incorrectly managed in mw.language:FormatNum() and even forgotten due to an internal bug, e.g. in Hindi)
+    local exponent
+    local pos = string.find(number, '[Ee]')
+    if pos ~= nil then
+        exponent = string.sub(number, pos + 1, string.len(number))
+        number = string.sub(number, 1, pos - 1)
+    else
+        exponent = ''
+    end
+
+    -- Check the minimum precision requested
+    prec = tonumber(prec) -- nil if not specified as a true number
+    if prec ~= nil then
+        prec = math.floor(prec)
+        if prec < 0 then
+            prec = nil -- discard an incorrect precision (not a positive integer)
+        elseif prec > 14 then
+            prec = 14 -- maximum precision supported by tostring(number)
+        end
+    end
+
+    -- Preprocess the minimum precision in the ASCII string
+    local dot
+    if (prec or 0) > 0 then
+        pos = string.find(number, '.', 1, true) -- plain search, no regexp
+        if pos ~= nil then
+            prec = pos + prec - string.len(number) -- effective number of trailing decimals to add or remove
+            dot = '' -- already present
+        else
+            dot = '.' -- must be added
+        end
+    else
+        dot = '' -- don't add dot
+        prec = 0 -- don't alter the precision
+    end
+
+    if lang ~= nil and mw.language.isKnownLanguageTag(lang) == true then
+        -- Convert number to localized digits, decimal separator, and group separators
+        local language = mw.getLanguage(lang)
+        if compact then
+            number = language:formatNum(tonumber(number), { noCommafy = 'y' }) -- caveat: can load localized resources for up to 20 languages
+        else
+            number = language:formatNum(tonumber(number)) -- caveat: can load localized resources for up to 20 languages
+        end
+        -- Postprocessing the precision
+        if prec > 0 then
+            local zero = language:formatNum(0)
+            number = number .. dot .. mw.ustring.rep(zero, prec)
+        elseif prec < 0 then
+            -- TODO: rounding of last decimal; here only truncate decimals in excess
+            number = mw.ustring.sub(number, 1, mw.ustring.len(number) + prec)
+        end
+        -- Append the localized base-10 exponent without grouping separators (there's no reliable way to detect a localized leading symbol 'E')
+        if exponent ~= '' then
+            number = number .. 'E' .. language:formatNum(tonumber(exponent),{noCommafy=true})
+        end
+    else -- not localized, ASCII only
+        -- Postprocessing the precision
+        if prec > 0 then
+            number = number .. dot .. mw.string.rep('0', prec)
+        elseif prec < 0 then
+            -- TODO: rounding of last decimal; here only truncate decimals in excess
+            number = mw.string.sub(number, 1, mw.string.len(number) + prec)
+        end
+        -- Append the base-10 exponent
+        if exponent ~= '' then
+            number = number .. 'E' .. exponent
+        end
+    end
+
+    -- Special cases for substitution of ASCII digits (missing support in Lua core libraries for some languages)
+    if digit[lang] then
+        for i, v in ipairs(digit[lang]) do
+            number = mw.ustring.gsub(number, tostring(i - 1), v)
+        end
+    end
+
+    return number
+end
+
+return p