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Módulo:Lang/Testes

Origem: Wikipédia, a enciclopédia livre.
--[=[

Lua support for the {{lang}}, {{lang-xx}}, and {{transl}} templates and replacement of various supporting templates.

]=]

require('Module:No globals');

local getArgs = require ('Module:Arguments').getArgs;
local unicode = require ("Module:Unicode data");                                -- for is_latin() and is_rtl()
local yesno = require ('Module:Yesno');

local lang_data =  mw.loadData ('Module:Lang/data');                            -- language name override and transliteration tool-tip tables
local lang_name_table = lang_data.lang_name_table;                                -- language codes, names, regions, scripts, suppressed scripts
local lang_table = lang_data.lang_name_table.lang;
local lang_dep_table = lang_data.lang_name_table.lang_dep;
local script_table = lang_data.lang_name_table.script;
local region_table = lang_data.lang_name_table.region;
local variant_table = lang_data.lang_name_table.variant;
local suppressed_table = lang_data.lang_name_table.suppressed;
local override_table = lang_data.override;

local synonym_table = mw.loadData ('Module:Lang/ISO 639 synonyms');                -- ISO 639-2/639-2T code translation to 639-1 code

local namespace = mw.title.getCurrentTitle().namespace;                            -- used for categorization

local this_wiki_lang = mw.language.getContentLanguage().code;                    -- get this wiki's language

local initial_style_state;                                                        -- set by lang_xx_normal() and lang_xx_italic()

local maint_cats = {};                                                            -- maintenance categories go here
local maint_msgs = {};                                                            -- and their messages go here


--[[--------------------------< I S _ S E T >------------------------------------------------------------------

Returns true if argument is set; false otherwise. Argument is 'set' when it exists (not nil) or when it is not an empty string.

]]

local function is_set( var )
    return not (var == nil or var == '');
end


--[[--------------------------< I N V E R T  _ I T A L I C S >-------------------------------------------------

This function attempts to invert the italic markup a args.text by adding/removing leading/trailing italic markup
in args.text.  Like |italic=unset, |italic=invert disables automatic italic markup.  Individual leading/trailing
apostrophes are converted to their html numeric entity equivalent so that the new italic markup doesn't become
bold markup inadvertently.

Leading and trailing wiki markup is extracted from args.text into separate table elements.  Addition, removal,
replacement of wiki markup is handled by a string.gsub() replacement table operating only on these separate elements.
In the string.gsub() matching pattern, '.*' matches empty string as well as the three expected wiki markup patterns.

This function expects that markup in args.text is complete and correct; if it is not, oddness may result.

]]

local function invert_italics (source)
    local invert_pattern_table = {                                                -- leading/trailing markup add/remove/replace patterns
        [""]="\'\'",                                                            -- empty string becomes italic markup
        ["\'\'"]="",                                                            -- italic markup becomes empty string
        ["\'\'\'"]="\'\'\'\'\'",                                                -- bold becomes bold italic
        ["\'\'\'\'\'"]="\'\'\'",                                                -- bold italic become bold
        };
    local seg = {};

    source = source:gsub ("%f[\']\'%f[^\']", '&#39;');                            -- protect single quote marks from being interpreted as bold markup

    seg[1] = source:match ('^(\'\'+%f[^\']).+') or '';                            -- get leading markup, if any; ignore single quote
    seg[3] = source:match ('.+(%f[\']\'\'+)$') or '';                            -- get trailing markup, if any; ignore single quote

    if '' ~= seg[1] and '' ~= seg[3] then                                        -- extract the 'text'
        seg[2] = source:match ('^\'\'+%f[^\'](.+)%f[\']\'\'+$')                    -- from between leading and trailing markup
    elseif '' ~= seg[1] then
        seg[2] = source:match ('^\'\'+%f[^\'](.+)')                                -- following leading markup
    elseif '' ~= seg[3] then
        seg[2] = source:match ('(.+)%f[\']\'\'+$')                                -- preceding trailing markup
    else
        seg[2] = source                                                            -- when there is no markup
    end

    seg[1] = invert_pattern_table[seg[1]] or seg[1];                            -- replace leading markup according to pattern table
    seg[3] = invert_pattern_table[seg[3]] or seg[3];                            -- replace leading markup according to pattern table

    return table.concat (seg);                                                    -- put it all back together and done
end


--[[--------------------------< V A L I D A T E _ I T A L I C >------------------------------------------------

validates |italic= or |italics= assigned values.

When |italic= is set and has an acceptible assigned value, return the matching css font-style property value or,
for the special case 'default', return nil.

When |italic= is not set, or has an unacceptible assigned value, return nil and a nil error message.

When both |italic= and |italics= are set, returns nil and a 'conflicting' error message.

The return value nil causes the calling lang, lang_xx, or transl function to set args.italic according to the template's
defined default ('inherit' for {{lang}}, 'inherit' or 'italic' for {{lang-xx}} depending on
the individual template's requirements, 'italic' for {{transl}}) or to the value appropriate to |script=, if set ({{lang}}
and {{lang-xx}} only).

Accepted values and the values that this function returns are are:
    nil        -    when |italic= absent or not set; returns nil
    default    -    for completeness, should rarely if ever be used; returns nil
    yes        -    force args.text to be rendered in italic font; returns 'italic'
    no        -    force args.text to be rendered in normal font; returns 'normal'
    unset    -    disables font control so that font-style applied to text is dictated by markup inside or outside the template; returns 'inherit'
    invert    -    disables font control so that font-style applied to text is dictated by markup outside or inverted inside the template; returns 'invert'

]]

local function validate_italic (args)
    local properties = {['yes'] = 'italic', ['no'] = 'normal', ['unset'] = 'inherit', ['invert'] = 'invert', ['default'] = nil};
   
    local count = 0
    for _, arg in pairs {'italic', 'italics', 'i'} do
        if args[arg] then
            count = count + 1
        end
    end

    if count > 1 then                                                            -- return nil and an error message if more than one is set
        return nil, 'only one of |italic=, |italics=, or |i= can be specified';
    end
   
    return properties[args.italic or args.italics or args.i], nil;                -- return an appropriate value and a nil error message
end


--[=[--------------------------< V A L I D A T E _ C A T _ A R G S >----------------------------------------------------------

Default behavior of the {{lang}} and {{lang-xx}} templates is to add categorization when the templates are used in mainspace.
This default functionality may be suppressed by setting |nocat=yes or |cat=no.  This function selects one of these two parameters
to control categorization.

Because having two parameters with 'opposite' names and 'opposite' values is confusing, this function accepts only affirmative
values for |nocat= and only negative values for |cat=; in both cases the 'other' sense (and non-sense) is not accepted and the
parameter is treated as if it were not set in the template.

Sets args.nocat to true if categorization is to be turned off; to nil if the default behavior should apply.

Accepted values for |nocat= are the text strings:
    'yes', 'y', 'true', 't', on, '1'        -- [[Module:Yesno]] returns logical true for all of these; false or nil else
for |cat=
    'no', 'n', 'false', 'f', 'off', '0'        -- [[Module:Yesno]] returns logical false for all of these; true or nil else

]=]

local function validate_cat_args (args)
    if not (args.nocat or args.cat) then                                        -- both are nil, so categorize
        return;
    end
   
    if false == yesno (args.cat) or true == yesno (args.nocat) then
        args.nocat = true;                                                        -- set to true when args.nocat is affirmative; nil else (as if the parameter were not set in the template)
    else                                                                        -- args.nocat is the parameter actually used.
        args.nocat = nil;
    end
end


--[[--------------------------< I N _ A R R A Y >--------------------------------------------------------------

Whether needle is in haystack

]]

local function in_array ( needle, haystack )
    if needle == nil then
        return false;
    end
    for n,v in ipairs( haystack ) do
        if v == needle then
            return n;
        end
    end
    return false;
end


--[[--------------------------< F O R M A T _ I E T F _ T A G >------------------------------------------------

prettify ietf tags to use recommended subtag formats:
    code: lower case
    script: sentence case
    region: upper case
    variant: lower case
    private: lower case prefixed with -x-
   
]]

local function format_ietf_tag (code, script, region, variant, private)
    local out = {};

    if is_set (private) then
        return table.concat ({code:lower(), 'x', private:lower()}, '-');        -- if private, all other tags ignored
    end
   
    table.insert (out, code:lower());
    if is_set (script) then
        script = script:lower():gsub ('^%a', string.upper);
        table.insert (out, script);
    end

    if is_set (region) then
        table.insert (out, region:upper());
    end
   
    if is_set (variant) then
        table.insert (out, variant:lower());
    end
   
    return table.concat (out, '-');
end


--[[--------------------------< G E T _ I E T F _ P A R T S >--------------------------------------------------

extracts and returns IETF language tag parts:
    primary language subtag (required) - 2 or 3 character IANA language code
    script subtag - four character IANA script code
    region subtag - two-letter or three digit IANA region code
    variant subtag - four digit or 5-8 alnum variant code; only one variant subtag supported
    private subtag - x- followed by 1-8 alnum private code; only supported with the primary language tag

in any one of these forms
    lang                    lang-variant
    lang-script                lang-script-variant
    lang-region                lang-region-variant
    lang-script-region        lang-script-region-variant
    lang-x-private   
   
each of lang, script, region, variant, and private, when used, must be valid

Languages with both two- and three-character code synonyms are promoted to the two-character synonym because
the IANA registry file omits the synonymous three-character code; we cannot depend on browsers understanding
the synonymous three-character codes in the lang= attribute.

For {{lang-xx}} templates, the parameters |script=, |region=, and |variant= are supported (not supported in {{lang}}
because those parameters are superfluous to the IETF subtags in |code=)

returns six  values; all lower case.  Valid parts are returned as themselves; omitted parts are returned as empty strings, invalid
parts are returned as nil; the sixth returned item is an error message (if an error detected) or nil.

see http://www.rfc-editor.org/rfc/bcp/bcp47.txt section 2.1

]]

local function get_ietf_parts (source, args_script, args_region, args_variant)
    local code, script, region, variant, private;                                -- ietf tag parts

    if not is_set (source) then
        return nil, nil, nil, nil, nil, 'missing language tag';
    end

    local pattern = {                                                            -- table of tables holding acceptibe ietf tag patterns and short names of the ietf part captured by the pattern
        {'^(%a%a%a?)%-(%a%a%a%a)%-(%a%a)%-(%d%d%d%d)$', 's', 'r', 'v'},                 -- 1 -  ll-Ssss-RR-variant (where variant is 4 digits)
        {'^(%a%a%a?)%-(%a%a%a%a)%-(%d%d%d)%-(%d%d%d%d)$', 's', 'r', 'v'},                -- 2 -  ll-Ssss-DDD-variant (where region is 3 digits; variant is 4 digits)
        {'^(%a%a%a?)%-(%a%a%a%a)%-(%a%a)%-(%w%w%w%w%w%w?%w?%w?)$', 's', 'r', 'v'},        -- 3 -  ll-Ssss-RR-variant (where variant is 5-8 alnum characters)
        {'^(%a%a%a?)%-(%a%a%a%a)%-(%d%d%d)%-(%w%w%w%w%w%w?%w?%w?)$', 's', 'r', 'v'},    -- 4 -  ll-Ssss-DDD-variant (where region is 3 digits; variant is 5-8 alnum characters)
       
        {'^(%a%a%a?)%-(%a%a%a%a)%-(%d%d%d%d)$', 's', 'v'},                        -- 5 -  ll-Ssss-variant (where variant is 4 digits)
        {'^(%a%a%a?)%-(%a%a%a%a)%-(%w%w%w%w%w%w?%w?%w?)$', 's', 'v'},            -- 6 -  ll-Ssss-variant (where variant is 5-8 alnum characters)
       
        {'^(%a%a%a?)%-(%a%a)%-(%d%d%d%d)$', 'r', 'v'},                            -- 7 -  ll-RR-variant (where variant is 4 digits)
        {'^(%a%a%a?)%-(%d%d%d)%-(%d%d%d%d)$', 'r', 'v'},                        -- 8 -  ll-DDD-variant (where region is 3 digits; variant is 4 digits)
        {'^(%a%a%a?)%-(%a%a)%-(%w%w%w%w%w%w?%w?%w?)$', 'r', 'v'},                -- 9 -  ll-RR-variant (where variant is 5-8 alnum characters)
        {'^(%a%a%a?)%-(%d%d%d)%-(%w%w%w%w%w%w?%w?%w?)$', 'r', 'v'},                -- 10 - ll-DDD-variant (where region is 3 digits; variant is 5-8 alnum characters)
       
        {'^(%a%a%a?)%-(%d%d%d%d)$', 'v'},                                        -- 11 - ll-variant (where variant is 4 digits)
        {'^(%a%a%a?)%-(%w%w%w%w%w%w?%w?%w?)$', 'v'},                            -- 12 - ll-variant (where variant is 5-8 alnum characters)
       
        {'^(%a%a%a?)%-(%a%a%a%a)%-(%a%a)$', 's', 'r'},                            -- 13 - ll-Ssss-RR
        {'^(%a%a%a?)%-(%a%a%a%a)%-(%d%d%d)$', 's', 'r'},                        -- 14 - ll-Ssss-DDD (region is 3 digits)
       
        {'^(%a%a%a?)%-(%a%a%a%a)$', 's'},                                        -- 15 - ll-Ssss
       
        {'^(%a%a%a?)%-(%a%a)$', 'r'},                                            -- 16 - ll-RR
        {'^(%a%a%a?)%-(%d%d%d)$', 'r'},                                            -- 17 - ll-DDD (region is 3 digits)
       
        {'^(%a%a%a?)$'},                                                        -- 18 - ll
       
        {'^(%a%a%a?)%-x%-(%w%w?%w?%w?%w?%w?%w?%w?)$', 'p'},                        -- 19 - ll-x-pppppppp (private is 1-8 alnum characters)
        }

    local t = {};                                                                -- table of captures; serves as a translator between captured ietf tag parts and named variables

    for i, v in ipairs (pattern) do                                                -- spin through the pattern table looking for a match
        local c1, c2, c3, c4;                                                    -- captures in the 'pattern' from the pattern table go here
   
        c1, c2, c3, c4 = source:match (pattern[i][1]);                            -- one or more captures set if source matches pattern[i])
            if c1 then                                                            -- c1 always set on match
                code = c1;                                                        -- first capture is always code
                t = {
                    [pattern[i][2] or 'x'] = c2,                                -- fill the table of captures with the rest of the captures
                    [pattern[i][3] or 'x'] = c3,                                -- take index names from pattern table and assign sequential captures
                    [pattern[i][4] or 'x'] = c4,                                -- index name may be nil in pattern[i] table so "or 'x'" spoofs a name for this index in this table
                    };
                script = t.s or '';                                                -- translate table contents to named variables;
                region = t.r or '';                                                -- absent table entries are nil so set named ietf parts to empty string for concatenation
                variant= t.v or '';
                private = t.p or '';
                break;                                                            -- and done
            end
    end

    if not code then
        return nil, nil, nil, nil, nil, table.concat ({'unrecognized language tag: ', source});        -- don't know what we got but it is malformed
    end

    code = code:lower();                                                        -- ensure that we use and return lower case version of this
   
    if not (override_table[code] or lang_table[code] or synonym_table[code] or lang_dep_table[code]) then
        return nil, nil, nil, nil, nil, table.concat ({'unrecognized language code: ', code});        -- invalid language code, don't know about the others (don't care?)
    end
   
    if synonym_table[code] then                                                    -- if 639-2/639-2T code has a 639-1 synonym
        table.insert (maint_cats, table.concat ({'Lang and lang-xx code promoted to ISO 639-1|', code}));
        table.insert (maint_msgs, table.concat ({'code: ', code, ' promoted to code: ', synonym_table[code]}));
        code = synonym_table[code];                                                -- use the synonym
    end

    if is_set (script) then
        if is_set (args_script) then
            return code, nil, nil, nil, nil, 'redundant script tag';            -- both code with script and |script= not allowed
        end
    else
        script = args_script or '';                                                -- use args.script if provided
    end

    if is_set (script) then
        script = script:lower();                                                -- ensure that we use and return lower case version of this
        if not script_table[script] then
            return code, nil, nil, nil, nil, table.concat ({'unrecognized script: ', script, ' for code: ', code});    -- language code ok, invalid script, don't know about the others (don't care?)
        end
    end
    if suppressed_table[script] then                                            -- ensure that code-script does not use a suppressed script
        if in_array (code, suppressed_table[script]) then
            return code, nil, nil, nil, nil, table.concat ({'script: ', script, ' not supported for code: ', code});    -- language code ok, script is suppressed for this code
        end
    end

    if is_set (region) then
        if is_set (args_region) then
            return code, nil, nil, nil, nil, 'redundant region tag';            -- both code with region and |region= not allowed
        end
    else
        region = args_region or '';                                                -- use args.region if provided
    end

    if is_set (region) then
        region = region:lower();                                                -- ensure that we use and return lower case version of this
        if not region_table[region] then
            return code, script, nil, nil, nil, table.concat ({'unrecognized region: ', region, ' for code: ', code});
        end
    end
   
    if is_set (variant) then
        if is_set (args_variant) then
            return code, nil, nil, nil, nil, 'redundant variant tag';            -- both code with variant and |variant= not allowed
        end
    else
        variant = args_variant or '';                                            -- use args.variant if provided
    end

    if is_set (variant) then
        variant = variant:lower();                                                -- ensure that we use and return lower case version of this
        if not variant_table[variant] then                                        -- make sure variant is valid
            return code, script, region, nil, nil, table.concat ({'unrecognized variant: ', variant});
        end                                                                        -- does this duplicate/replace tests in lang() and lang_xx()?
        if is_set (script) then                                                    -- if script set it must be part of the 'prefix'
            if not in_array (table.concat ({code, '-', script}), variant_table[variant]['prefixes']) then
                return code, script, region, nil, nil, table.concat ({'unrecognized variant: ', variant, ' for code-script pair: ', code, '-', script});
            end
        elseif is_set (region) then                                                -- if region set, there are some prefixes that require lang code and region (en-CA-newfound)
            if not in_array (code, variant_table[variant]['prefixes']) then        -- first see if lang code is all that's required (en-oxendict though en-GB-oxendict is preferred)
                if not in_array (table.concat ({code, '-', region}), variant_table[variant]['prefixes']) then        -- now try for lang code and region (en-CA-newfound)
                    return code, script, region, nil, nil, table.concat ({'unrecognized variant: ', variant, ' for code-region pair: ', code, '-', region});
                end
            end
        else
            if not in_array (code, variant_table[variant]['prefixes']) then
                return code, script, region, nil, nil, table.concat ({'unrecognized variant: ', variant, ' for code: ', code});
            end               
        end
    end
   
    if is_set (private) then
        private = private:lower();                                                -- ensure that we use and return lower case version of this
        if not override_table[table.concat ({code, '-x-', private})] then        -- make sure private tag is valid; note that index
            return code, script, region, nil, nil, table.concat ({'unrecognized private tag: ', private});
        end
    end
    return code, script, region, variant, private, nil;                            -- return the good bits; make sure that msg is nil
end


--[[--------------------------< M A K E _ E R R O R _ M S G >--------------------------------------------------

assembles an error message from template name, message text, help link, and error category.

]]

local function make_error_msg (msg, args, template)
    local out = {};
    local category;
   
    if 'Transl' == template then
        category = 'Transl';
    else
        category = 'Lang and lang-xx'
    end
   
    table.insert (out, table.concat ({'[', args.text or 'undefined', '] '}));    -- for error messages output args.text if available
    table.insert (out, table.concat ({'<span style=\"font-size: 100%; font-style: normal;\" class=\"error\">Error: {{', template, '}}: '}));
    table.insert (out, msg);
    table.insert (out, table.concat ({' ([[:Category:', category, ' template errors|help]])'}));
    table.insert (out, '</span>');
   
    if (0 == namespace or 10 == namespace) and not args.nocat then                        -- categorize in article space (and template space to take care of broken usages)
        table.insert (out, table.concat ({'[[Category:', category, ' template errors]]'}));
    end

    return table.concat (out);
end
   

--[=[-------------------------< M A K E _ W I K I L I N K >----------------------------------------------------

Makes a wikilink; when both link and display text is provided, returns a wikilink in the form [[L|D]]; if only
link is provided, returns a wikilink in the form [[L]]; if neither are provided or link is omitted, returns an
empty string.

]=]

local function make_wikilink (link, display)
    if is_set (link) then
        if is_set (display) then
            return table.concat ({'[[', link, '|', display, ']]'});
        else
            return table.concat ({'[[', link, ']]'});
        end
    else
        return '';
    end
end


--[[--------------------------< D I V _ M A R K U P _ A D D >--------------------------------------------------

adds <i> and </i> tags to list-item text or to implied <p>..</p> text.  mixed not supported

]]

local function div_markup_add (text, style)
local implied_p = {};

    if text:find ('^\n[%*:;#]') then                                            -- look for list markup; list markup must begin at start of text
        if 'italic' == style then
            return mw.ustring.gsub (text, '(\n[%*:;#]+)([^\n]+)', '%1<i>%2</i>');    -- insert italic markup at each list item
        else
            return text;
        end
    end

    if text:find ('\n+') then                                                    -- look for any number of \n characters in text
        text = text:gsub ('([^\n])\n([^\n])', '%1 %2');                            -- replace single newline characters with a space character which mimics mediawiki

        if 'italic' == style then
            text = text:gsub('[^\n]+', '<p><i>%1</i></p>');                        -- insert p and italic markup tags at each impled p (two or more consecutive '\n\n' sequences)
        else
            text = text:gsub ('[^\n]+', '<p>%1</p>');                            -- insert p markup at each impled p
            text = text:gsub ('\n', '');                                        -- strip newline characters
        end
    end

    return text;
end


--[[--------------------------< M A K E _ T E X T _ H T M L >--------------------------------------------------

Add the html markup to text according to the type of content that it is: <span> or <i> tags for inline content or
<div> tags for block content

]]

local function make_text_html (code, text, tag, rtl, style, size, language)
    local html = {};
    local style_added = '';

    if text:match ('^%*') then
        table.insert (html, '&#42;');                                            -- move proto language text prefix outside of italic markup if any; use numeric entity because plain splat confuses MediaWiki
        text = text:gsub ('^%*', '');                                            -- remove the splat from the text
    end

    if 'span' == tag then                                                        -- default html tag for inline content
        if 'italic' == style then                                                -- but if italic
            tag = 'i';                                                            -- change to <i> tags
        end
    else                                                                        -- must be div so go
        text = div_markup_add (text, style);                                    -- handle implied <p>, implied <p> with <i>, and list markup (*;:#) with <i>
    end

    table.insert (html, table.concat ({'<', tag}));                                -- open the <i>, <span>, or <div> html tag
    table.insert (html, table.concat ({' lang="', code, '\"'}));                -- add language attribute

    if rtl or unicode.is_rtl(text) then
        table.insert (html, ' dir="rtl"');                                        -- add direction attribute for right to left languages
    end

    if 'normal' == style then                                                    -- when |italic=no
        table.insert (html, ' style=\"font-style: normal;');                        -- override external markup, if any
        style_added = '\"';                                                        -- remember that style attribute added and is not yet closed
    end

    if is_set (size) then                                                        -- when |size=<something>
        if is_set (style_added) then
            table.insert (html, table.concat ({' font-size: ', size, ';'}));        -- add when style attribute already inserted
        else
            table.insert (html, table.concat ({' style=\"font-size: ', size, ';'}));    -- create style attribute
            style_added = '\"';                                                    -- remember that style attribute added and is not yet closed
        end
    end

    if is_set (language) then
        table.insert (html, table.concat ({style_added, ' title=\"', language}));    --start the title text
        if language:find ('languages') then
            table.insert (html, ' collective text');                            -- for collective languages
        else
            table.insert (html, '-language text');                                -- for individual languages
        end
        table.insert (html, '\">');                                                -- close the opening html tag
    else
        table.insert (html, table.concat ({style_added, '>'}));                    -- close the style attribute and close opening html tag
    end
    table.insert (html, text);                                                    -- insert the text

    table.insert (html, table.concat ({'</', tag, '>'}));                        -- close the <i>, <span>, or <div> html tag

    if rtl then                                                                    -- legacy; shouldn't be necessary because all of the rtl text is wrapped inside an html tag with dir="rtl" attribute
        table.insert (html, '&lrm;');                                            -- make sure the browser knows that we're at the end of the rtl
    end
    return table.concat (html);                                                    -- put it all together and done
end


--[=[-------------------------< M A K E _ C A T E G O R Y >----------------------------------------------------

For individual language, <language>, returns:
    [[Category:Articles containing <language>-language text]]

for English:
    [[Category:Articles containing explicitly cited English-language text]]
   
for ISO 639-2 collective languages (and for 639-1 bh):
    [[Category:Articles with text in <language> languages]]

]=]

local function make_category (code, language_name, nocat, name_get)
    local cat = {};
    local retval;

    if ((0 ~= namespace) or nocat) and not name_get then                        -- only categorize in article space
        return '';                                                                -- return empty string for concatenation
    end

    if language_name:find ('languages') then
        return table.concat ({'[[Category:Articles with text in ', language_name, ']]'});
    end
       
    table.insert (cat, '[[Category:Articles containing ');

    if 'en' == code then
        table.insert (cat, 'explicitly cited ' .. language_name);                -- falls back to English if regional name not available
    else
        table.insert (cat, language_name);
    end
   
    table.insert (cat, '-language text]]');

    return table.concat (cat);
end


--[[--------------------------< M A K E _ T R A N S L I T >----------------------------------------------------

return translit <i lang=xx-Latn>...</i> where xx is the language code; else return empty string

The value |script= is not used in {{transl}} for this purpose; instead it uses |code.  Because language scripts
are listed in the {{transl}} switches they are included in the data tables.  The script parameter is introduced
at {{Language with name and transliteration}}.  If |script= is set, this function uses it in preference to code.

To avoid confusion, in this module and the templates that use it, the transliteration script parameter is renamed
to be |translit-script= (in this function, tscript)

This function is used by both lang_xx() and transl()
    lang_xx() always provides code, language_name, and translit; may provide tscript; never provides style
    transl() always provides language_name, translit, and one of code or tscript, never both; always provides style

For {{transl}}, style only applies when a language code is provided
]]

local function make_translit (code, language_name, translit, std, tscript, style)
    local title;
    local tout = {};
    local title_table = lang_data.translit_title_table;                            -- table of transliteration standards and the language codes and scripts that apply to those standards
   
    if is_set (code) then                                                        -- when a language code is provided (always with {{lang-xx}} templates, not always with {{transl}})
        if not style then                                                        -- nil for the default italic style
            table.insert (tout, "<i lang=\"");                                    -- so use <i> tag
        else
            table.insert (tout, table.concat ({'<span style=\"font-style: ', style, '\" lang=\"'}));    -- non-standard style, construct a span tag for it
        end
        table.insert (tout, code);
        table.insert (tout, "-Latn\" title=\"");                                -- transliterations are always Latin script
    else
        table.insert (tout, "<span title=\"");                                    -- when no language code: no lang= attribute, not italic ({{transl}} only)
    end
   
    std = std and std:lower();                                                    -- lower case for table indexing
   
    if not is_set (std) and not is_set (tscript) then                            -- when neither standard nor script specified
        table.insert (tout, language_name);                                        -- write a generic tool tip
        if not language_name:find ('languages') then                            -- collective language names (plural 'languages' is part of the name)
            table.insert (tout, '-language')                                    -- skip this text (individual and macro languages only)
        end
        table.insert (tout, ' romanization');                                    -- finish the tool tip; use romanization when neither script nor standard supplied
    elseif is_set (std) and is_set (tscript) then                                -- when both are specified
        if title_table[std] then                                                -- and if standard is legitimate
            if title_table[std][tscript] then                                    -- and if script for that standard is legitimate
                table.insert (tout, table.concat ({title_table[std][tscript:lower()], ' (', script_table[tscript][1], ' script) transliteration'}));    -- add the appropriate text to the tool tip
            else
                table.insert (tout, title_table[std]['default']);                -- use the default if script not in std table; TODO: maint cat? error message because script not found for this standard?
            end
        else
            return '';                                                            -- invalid standard, setup for error message
        end

    elseif is_set (std) then                                                    -- translit-script not set, use language code
        if not title_table[std] then return ''; end                                -- invalid standard, setup for error message
       
        if title_table[std][code] then                                            -- if language code is in the table (transl may not provide a language code)
--            table.insert (tout, table.concat ({title_table[std][code:lower()], ' (', lang_table[code][1], ' language) transliteration'}));    -- add the appropriate text to the tool tip
            table.insert (tout, table.concat ({title_table[std][code:lower()], ' (', language_name, ' language) transliteration'}));    -- add the appropriate text to the tool tip
        else                                                                    -- code doesn't match
            table.insert (tout, title_table[std]['default']);                    -- so use the standard's default
        end
    else                                                                        -- here if translit-script set but translit-std not set
        if title_table['no_std'][tscript] then
            table.insert (tout, title_table['no_std'][tscript]);                -- use translit-script if set
        elseif title_table['no_std'][code] then
            table.insert (tout, title_table['no_std'][code]);                    -- use language code
        else
            if is_set (tscript) then
                table.insert (tout, table.concat ({language_name, '-script transliteration'}));    -- write a script tool tip
            elseif is_set (code) then
                if not language_name:find ('languages') then                    -- collective language names (plural 'languages' is part of the name)
                    table.insert (tout, '-language')                            -- skip this text (individual and macro languages only)
                end
                table.insert (tout, ' transliteration');                        -- finish the tool tip
            else
                table.insert (tout, ' transliteration');                        -- generic tool tip (can we ever get here?)
            end
        end
    end

    table.insert (tout, '">');
    table.insert (tout, translit);
    if is_set (code) and not style then                                            -- when a language code is provided (always with {{lang-xx}} templates, not always with {{transl}})
        table.insert (tout, "</i>");                                            -- close the italic tag
    else
        table.insert (tout, "</span>");                                            -- no language code so close the span tag
    end
    return table.concat (tout);
end


--[[--------------------------< V A L I D A T E _ T E X T >----------------------------------------------------

This function checks the content of args.text and returns empty string if nothing is amiss else it returns an
error message.  The tests are for empty or missing text and for improper or disallowed use of apostrophe markup.

Italic rendering is controlled by the |italic= template parameter so italic markup should never appear in args.text
either as ''itself'' or as '''''bold italic''''' unless |italic=unset or |italic=invert.

]]

local function validate_text (template, args)
    if not is_set (args.text) then
        return make_error_msg ('no text', args, template);
    end

    if args.text:find ("%f[\']\'\'\'\'%f[^\']") or args.text:find ("\'\'\'\'\'[\']+") then    -- because we're looking, look for 4 appostrophes or 6+ appostrophes
        return make_error_msg ('text has malformed markup', args, template);
    end

    local style = args.italic;

    if ('unset' ~= style) and ('invert' ~=style) then
        if args.text:find ("%f[\']\'\'%f[^\']") or args.text:find ("%f[\']\'\'\'\'\'%f[^\']") then    -- italic but not bold, or bold italic
            return make_error_msg ('text has italic markup', args, template);
        end
    end
end


--[[--------------------------< R E N D E R _ M A I N T >------------------------------------------------------

render mainenance messages and categories

]]

local function render_maint(nocat)
    local maint = {};
   
    if 0 < #maint_msgs then                                                        -- when there are maintenance messages
        table.insert (maint, table.concat ({'<span class="lang-comment" style="font-style: normal; display: none; color: #33aa33; margin-left: 0.3em;">'}));    -- opening <span> tag
        for _, msg in ipairs (maint_msgs) do
            table.insert (maint, table.concat ({msg, ' '}));                    -- add message strings
        end
        table.insert (maint, '</span>');                                        -- close the span
    end
   
    if (0 < #maint_cats) and (0 == namespace) and not nocat then                -- when there are maintenance categories; article namespace only
        for _, cat in ipairs (maint_cats) do
            table.insert (maint, table.concat ({'[[Category:', cat, ']]'}));    -- format and add the categories
        end
    end
   
    return table.concat (maint);
end


--[[--------------------------< P R O T O _ P R E F I X >------------------------------------------------------

for proto languages, text is prefixed with a splat.  We do that here as a flag for make_text_html() so that a splat
will be rendered outside of italic markup (if used).  If the first character in text here is already a splat, we
do nothing

proto_param is boolean or nil; true adds splat prefix regardless of language name; false removes and / or inhibits
regardless of language name; nil does nothing; presumes that the value in text is correct but removes extra splac

]]

local function proto_prefix (text, language_name, proto_param)
    if false == proto_param then                                                -- when forced by |proto=no
        return text:gsub ('^%**', '');                                            -- return text without splat prefix regardless of language name or existing splat prefix in text
    elseif (language_name:find ('^Proto%-') or (true == proto_param)) then        -- language is a proto or forced by |proto=yes
        return text:gsub ('^%**', '*');                                            -- prefix proto-language text with a splat; also removes duplicate prefixing splats
    end
   
    return text:gsub ('^%*+', '*');                                                -- return text unmolested except multiple splats reduced to one splat
end


--[[--------------------------< H A S _ P O E M _ T A G >------------------------------------------------------

looks for a poem strip marker in text; returns true when found; false else

auto-italic detection disabled when text has poem stripmarker because it is not possible for this code to know
the content that will replace the stripmarker.

]]

local function has_poem_tag (text)
    return text:find ('\127[^\127]*UNIQ%-%-poem%-[%a%d]+%-QINU[^\127]*\127') and true or false;
end


--[[--------------------------< H T M L _ T A G _ S E L E C T >------------------------------------------------

Inspects content of and selectively trims text.  Returns text and the name of an appropriate html tag for text.

If text contains:
    \n\n    text has implied <p>..</p> tags - trim leading and trailing whitespace and return
If text begins with list markup:
    \n*        unordered
    \n;        definition
    \n:        definition
    \n#        ordered
trim all leading whitespace except  \n and trim all trailing whitespace

If text contains <poem>...</poem> stripmarker, return text unmodified and choose <div>..</div> tags because
the stripmarker is replaced with text wrapped in <div>..</div> tags.

]]

local function html_tag_select (text)
    local tag;
   
    if has_poem_tag (text) then                                                    -- contains poem stripmarker (we can't know the content of that)
        tag = 'div';                                                            -- poem replacement is in div tags so lang must use div tags
    elseif mw.text.trim (text):find ('\n\n+') then                                -- contains implied p tags
        text = mw.text.trim (text);                                                -- trim leading and trailing whitespace characters
        tag = 'div';                                                            -- must be div because span may not contain p tags (added later by MediaWiki); poem replacement is in div tags
    elseif text:find ('\n[%*:;%#]') then                                        -- if text has list markup
        text = text:gsub ('^[\t\r\f ]*', ''):gsub ('%s*$', '');                    -- trim all whitespace except leading newline character '\n'
        tag = 'div';                                                            -- must be div because span may not contain ul, dd, dl, ol tags (added later by MediaWiki)
    else
        text = mw.text.trim (text);                                                -- plain text
        tag = 'span';                                                            -- so span is fine
    end
   
    return text, tag;
end


--[[--------------------------< V A L I D A T E _ P R O T O >--------------------------------------------------

validates value assigned to |proto=; permitted values are yes and no; yes returns as true, no returns as false,
empty string (or parameter omitted) returns as nil; any other value returns as nil with a second return value of
true indicating that some other value has been assigned to |proto=

]]

local function validate_proto (proto_param)
    if 'yes' == proto_param then
        return true;
    elseif 'no' == proto_param then
        return false;
    elseif is_set (proto_param) then
        return nil, true;                                                        -- |proto= something other than 'yes' or 'no'
    else
        return nil;                                                                -- missing or empty
    end
end


--[[--------------------------< L A N G U A G E _ N A M E _ G E T >--------------------------------------------

common function to return language name from the data set according to IETF tag

returns language name if found in data tables; nil else

]]

local function language_name_get (ietf, code, cat)
    ietf = ietf:lower();                                                        -- ietf:lower() because format_ietf_tag() returns mixed case
   
    local name;                                                                    -- remains nil if not found
   
    if override_table[ietf] then                                                -- look for whole IETF tag in override table
        name = override_table[ietf][1];   
    elseif override_table[code] then                                            -- not there so try basic language code
        name = override_table[code][1];
    elseif lang_table[code] then                                                -- shift to iana code/name table
        name = lang_table[code][1];                                                -- table entries sometimes have multiple names, always take the first one
    elseif lang_dep_table[code] then
--        if cat then
--            table.insert (maint_cats, table.concat ({'Lang and lang-xx using deprecated ISO 639 codes|', code}));
--            table.insert (maint_msgs, table.concat ({'code: ', code, ' is deprecated'}));
--        end
        name = lang_dep_table[code][1];                                            -- table entries sometimes have multiple names, always take the first one
    end

    if lang_dep_table[code] and cat then                                        -- because deprecated code may have been overridden to en.wiki preferred name
        table.insert (maint_cats, table.concat ({'Lang and lang-xx using deprecated ISO 639 codes|', code}));
        table.insert (maint_msgs, table.concat ({'code: ', code, ' is deprecated'}));
    end

    return name;                                                                -- name from data tables or nil
end


--[[--------------------------< _ L A N G >--------------------------------------------------------------------

entry point for {{lang}}

there should be no reason to set parameters in the {{lang}} {{#invoke:}}
    <includeonly>{{#invoke:lang|lang}}</includeonly>

parameters are received from the template's frame (parent frame)

]]

local function _lang (args)
    local out = {};
    local language_name;                                                        -- used to make category names
    local category_name;                                                        -- same as language_name except that it retains any parenthetical disambiguators (if any) from the data set
    local subtags = {};                                                            -- IETF subtags script, region, variant, and private
    local code;                                                                    -- the language code
    local msg;                                                                    -- for error messages
    local tag = 'span';                                                            -- initial value for make_text_html()
    local template = args.template or 'Lang';

    validate_cat_args (args);                                                    -- determine if categorization should be suppressed

    if args[1] and args.code then
        return make_error_msg ('conflicting: {{{1}}} and |code=', args, template);
    else
        args.code = args[1] or args.code;                                        -- prefer args.code
    end

    if args[2] and args.text then
        return make_error_msg ('conflicting: {{{2}}} and |text=', args, template);
    else
        args.text = args[2] or args.text;                                        -- prefer args.text
    end
   
    msg = validate_text (template, args);                                        -- ensure that |text= is set
    if is_set (msg) then                                                        -- msg is an already-formatted error message
        return msg;
    end
   
    args.text, tag = html_tag_select (args.text);                                -- inspects text; returns appropriate html tag with text trimmed accordingly

    args.rtl = args.rtl == 'yes';                                                -- convert to boolean: 'yes' -> true, other values -> false

    args.proto, msg = validate_proto (args.proto);                                -- return boolean, or nil, or nil and error message flag
    if msg then
        return make_error_msg (table.concat ({'invalid |proto=: ', args.proto}), args, template);
    end

    code, subtags.script, subtags.region, subtags.variant, subtags.private, msg = get_ietf_parts (args.code);    -- |script=, |region=, |variant= not supported because they should be part of args.code ({{{1}}} in {{lang}})

    if msg then
        return make_error_msg ( msg, args, template);
    end

    args.italic, msg = validate_italic (args);
    if msg then
        return make_error_msg (msg, args, template);
    end

    if nil == args.italic then                                                    -- nil when |italic= absent or not set or |italic=default; args.italic controls
        if ('latn' == subtags.script) or                                         -- script is latn
            (this_wiki_lang ~= code and not is_set (subtags.script) and not has_poem_tag (args.text) and unicode.is_Latin (args.text)) then -- text not this wiki's language, no script specified and not in poem markup but is wholly latn script (auto-italics)
                args.italic = 'italic';                                            -- DEFAULT for {{lang}} templates is upright; but if latn script set for font-style:italic
        else
            args.italic = 'inherit';                                            -- italic not set; script not latn; inherit current style
        end
    end
   
    if is_set (subtags.script) then                                                -- if script set, override rtl setting
        if in_array (subtags.script, lang_data.rtl_scripts) then
            args.rtl = true;                                                    -- script is an rtl script
        else
            args.rtl = false;                                                    -- script is not an rtl script
        end
    end

    args.code = format_ietf_tag (code, subtags.script, subtags.region, subtags.variant, subtags.private);    -- format to recommended subtag styles
    language_name = language_name_get (args.code, code, true);                    -- get language name; try ietf tag first, then code w/o variant then code w/ variant

    if 'invert' == args.italic and 'span' == tag then                            -- invert only supported for in-line content
        args.text = invert_italics (args.text)
    end

    args.text = proto_prefix (args.text, language_name, args.proto);            -- prefix proto-language text with a splat

    table.insert (out, make_text_html (args.code, args.text, tag, args.rtl, args.italic, args.size, language_name));
    table.insert (out, make_category (code, language_name, args.nocat));
    table.insert (out, render_maint(args.nocat));                                -- maintenance messages and categories

    return table.concat (out);                                                    -- put it all together and done
end


--[[--------------------------< L A N G >----------------------------------------------------------------------

entry point for {{lang}}

there should be no reason to set parameters in the {{lang}} {{#invoke:}}
    <includeonly>{{#invoke:lang|lang}}</includeonly>

parameters are received from the template's frame (parent frame)

]]

local function lang (frame)
    local args = getArgs (frame, {                                                -- this code so that we can detect and handle wiki list markup in text
        valueFunc = function (key, value)
            if 2 == key or 'text' == key then                                    -- the 'text' parameter; do not trim wite space
                return value;                                                    -- return untrimmed 'text'
            elseif value then                                                    -- all other values: if the value is not nil
                value = mw.text.trim (value);                                    -- trim whitespace
                if '' ~= value then                                                -- empty string when value was only whitespace
                    return value;
                end
            end
            return nil;                                                            -- value was empty or contained only whitespace
        end                                                                        -- end of valueFunc
        });

    return _lang (args);
end


--[[--------------------------< L A N G _ X X >----------------------------------------------------------------

For the {{lang-xx}} templates, the only parameter required to be set in the template is the language code.  All
other parameters can, usually should, be written in the template call.  For {{lang-xx}} templates for languages
that can have multiple writing systems, it may be appropriate to set |script= as well.

For each {{lang-xx}} template choose the appropriate entry-point function so that this function knows the default
styling that should be applied to text.

For normal, upright style:
    <includeonly>{{#invoke:lang|lang_xx_inherit|code=xx}}</includeonly>
For italic style:
    <includeonly>{{#invoke:lang|lang_xx_italic|code=xx}}</includeonly>

All other parameters should be received from the template's frame (parent frame)

Supported parameters are:
    |code = (required) the IANA language code
    |script = IANA script code; especially for use with languages that use multiple writing systems
    |region = IANA region code
    |variant = IANA variant code
    |text = (required) the displayed text in language specified by code
    |link = boolean false ('no') does not link code-spcified language name to associated language article
    |rtl = boolean true ('yes') identifies the language specified by code as a right-to-left language
    |nocat = boolean true ('yes') inhibits normal categorization; error categories are not affected
    |cat = boolian false ('no') opposite form of |nocat=
    |italic = boolean true ('yes') renders displayed text in italic font; boolean false ('no') renders displayed text in normal font; not set renders according to initial_style_state
    |lit = text that is a literal translation of text
    |label = 'none' to suppress all labeling (language name, 'translit.', 'lit.')
                any other text replaces language-name label - automatic wikilinking disabled
   
    for those {{lang-xx}} templates that support transliteration (those templates where |text= is not entirely latn script):
    |translit = text that is a transliteration of text
    |translit-std = the standard that applies to the transliteration
    |translit-script = ISO 15924 script name; falls back to code

For {{lang-xx}}, the positional parameters are:
    {{{1}}}    text
    {{{2}}}    transliterated text
    {{{3}}}    literal translation text
no other positional parameters are allowed

]]

local function _lang_xx (args)
    local out = {};
    local language_name;                                                        -- used to make display text, article links
    local category_name;                                                        -- same as language_name except that it retains any parenthetical disambiguators (if any) from the data set
    local subtags = {};                                                            -- IETF subtags script, region, and variant
    local code;                                                                    -- the language code

    local translit_script_name;                                                    -- name associated with IANA (ISO 15924) script code
    local translit;
    local translit_title;
    local msg;                                                                    -- for error messages
    local tag = 'span';                                                            -- initial value for make_text_html()
    local template = args.template or 'Lang-xx';

    if args[1] and args.text then
        return make_error_msg ('conflicting: {{{1}}} and |text=', args, template);
    else
        args.text = args[1] or args.text;                                        -- prefer args.text
    end
   
    msg = validate_text (template, args);                                        -- ensure that |text= is set, does not contain italic markup and is protected from improper bolding
    if is_set (msg) then
        return msg;
    end

    args.text, tag = html_tag_select (args.text);                                -- inspects text; returns appropriate html tag with text trimmed accordingly

    if args[2] and args.translit then
        return make_error_msg ('conflicting: {{{2}}} and |translit=', args, template);
    else
        args.translit = args[2] or args.translit                                -- prefer args.translit
    end
   
    if args[3] and (args.translation or args.lit) then
        return make_error_msg ('conflicting: {{{3}}} and |lit= or |translation=', args, template);
    elseif args.translation and args.lit then
        return make_error_msg ('conflicting: |lit= and |translation=', args, template);
    else
        args.translation = args[3] or args.translation or args.lit;                -- prefer args.translation
    end

    if args.links and args.link then
        return make_error_msg ('conflicting: |links= and |link=', args, template);
    else
        args.link = args.link or args.links;                                    -- prefer args.link
    end

    validate_cat_args (args);                                                    -- determine if categorization should be suppressed

    args.rtl = args.rtl == 'yes';                                                -- convert to boolean: 'yes' -> true, other values -> false

    code, subtags.script, subtags.region, subtags.variant, subtags.private, msg = get_ietf_parts (args.code, args.script, args.region, args.variant);    -- private omitted because private

    if msg then                                                                    -- if an error detected then there is an error message
        return make_error_msg (msg, args, template);
    end
   
    args.italic, msg = validate_italic (args);
    if msg then
        return make_error_msg (msg, args, template);
    end

    if nil == args.italic then                                                    -- args.italic controls
        if is_set (subtags.script) then
            if 'latn' == subtags.script then
                args.italic = 'italic';                                            -- |script=Latn; set for font-style:italic
            else
                args.italic = initial_style_state;                                -- italic not set; script is not latn; set for font-style:<initial_style_state>
            end
        else
            args.italic = initial_style_state;                                    -- here when |italic= and |script= not set; set for font-style:<initial_style_state>
        end
    end
   
    if is_set (subtags.script) then                                                -- if script set override rtl setting
        if in_array (subtags.script, lang_data.rtl_scripts) then
            args.rtl = true;                                                    -- script is an rtl script
        else
            args.rtl = false;                                                    -- script is not an rtl script
        end
    end

    args.proto, msg = validate_proto (args.proto);                                -- return boolean, or nil, or nil and error message flag
    if msg then
        return make_error_msg (table.concat ({'invalid |proto=: ', args.proto}), args, template);
    end

    args.code = format_ietf_tag (code, subtags.script, subtags.region, subtags.variant, subtags.private);    -- format to recommended subtag styles
    language_name = language_name_get (args.code, code, true);                    -- get language name; try ietf tag first, then code w/o variant then code w/ variant

    category_name = language_name;                                                -- category names retain IANA parenthetical diambiguators (if any)
    language_name = language_name:gsub ('%s+%b()', '');                            -- remove IANA parenthetical disambiguators or qualifiers from names that have them

    if args.label then
        if 'none' ~= args.label then
            table.insert (out, table.concat ({args.label, ': '}));                -- custom label
        end
    else
        if 'no' == args.link then
            table.insert (out, language_name);                                    -- language name without wikilink
        else
            if language_name:find ('languages') then
                table.insert (out, make_wikilink (language_name));                -- collective language name uses simple wikilink
            elseif lang_data.article_name[code] then
                table.insert (out, make_wikilink (lang_data.article_name[code][1], language_name));    -- language name with wikilink from override data
            else
                table.insert (out, make_wikilink (language_name .. ' language', language_name));    -- language name with wikilink
            end
        end
        table.insert (out, ': ');                                                -- separator
    end

    if 'invert' == args.italic then
        args.text = invert_italics (args.text)
    end
   
    args.text = proto_prefix (args.text, language_name, args.proto);            -- prefix proto-language text with a splat

    table.insert (out, make_text_html (args.code, args.text, tag, args.rtl, args.italic, args.size, ('none' == args.label) and language_name or nil))

    if is_set (args.translit) and not unicode.is_Latin (args.text) then            -- transliteration (not supported in {{lang}}); not supported when args.text is wholly latn text (this is an imperfect test)
        table.insert (out, ', ');                                                -- comma to separate text from translit
        if 'none' ~= args.label then
            table.insert (out, '<small>');
            if script_table[args['translit-script']] then                        -- when |translit-script= is set, try to use the script's name
                translit_script_name = script_table[args['translit-script'][1]];
            else
                translit_script_name = language_name;                            -- fall back on language name
            end
            translit_title = mw.title.makeTitle (0, table.concat ({'Romanization of ', translit_script_name}));        -- make a title object
            if translit_title.exists and ('no' ~= args.link) then
                table.insert (out, make_wikilink ('Romanization of ' .. translit_script_name or language_name, 'romanized') .. ':');    -- make a wikilink if there is an article to link to
            else
                table.insert (out, 'romanized:');                                -- else plain text
            end
            table.insert (out, '&nbsp;</small>');                                -- close the small tag
        end
       
        translit = make_translit (args.code, language_name, args.translit, args['translit-std'], args['translit-script'])
        if is_set (translit) then
            table.insert (out, translit);
        else
            return make_error_msg (table.concat ({'invalid translit-std: \'', args['translit-std'] or '[missing]'}), args, template);
        end
    end
   
    if is_set (args.translation) then                                            -- translation (not supported in {{lang}})
        table.insert (out, ', ');
        if 'none' ~= args.label then
            table.insert (out, '<small>');
            if 'no' == args.link then
                table.insert (out, '<abbr title="literal translation">lit.</abbr>');
            else
                table.insert (out, make_wikilink ('Literal translation', 'lit.'));
            end
            table.insert (out, "&nbsp;</small>");
        end
        table.insert (out, table.concat ({'&#39;', args.translation, '&#39;'}));    -- use html entities to avoid wiki markup confusion
    end
   
    table.insert (out, make_category (code, category_name, args.nocat));
    table.insert (out, render_maint(args.nocat));                                -- maintenance messages and categories

    return table.concat (out);                                                    -- put it all together and done
end


--[[--------------------------< L A N G _ X X _ A R G S _ G E T >----------------------------------------------

common function to get args table from {{lang-??}} templates

returns table of args

]]

local function lang_xx_args_get (frame)
    local args = getArgs(frame,
        {
        parentFirst= true,                                                        -- parameters in the template override parameters set in the {{#invoke:}}
        valueFunc = function (key, value)
            if 1 == key then                                                    -- the 'text' parameter; do not trim wite space
                return value;                                                    -- return untrimmed 'text'
            elseif value then                                                    -- all other values: if the value is not nil
                value = mw.text.trim (value);                                    -- trim whitespace
                if '' ~= value then                                                -- empty string when value was only whitespace
                    return value;
                end
            end
            return nil;                                                            -- value was empty or contained only whitespace
        end                                                                        -- end of valueFunc
    });

    return args;
end


--[[--------------------------< L A N G _ X X _ I T A L I C >--------------------------------------------------

Entry point for those {{lang-xx}} templates that call lang_xx_italic().  Sets the initial style state to italic.

]]

local function lang_xx_italic (frame)
    local args = lang_xx_args_get (frame);
   
    initial_style_state = 'italic';
    return _lang_xx (args);
end


--[[--------------------------< _ L A N G _ X X _ I T A L I C >------------------------------------------------

Entry point ffrom another module.  Sets the initial style state to italic.

]]

local function _lang_xx_italic (args)
    initial_style_state = 'italic';
    return _lang_xx (args);
end


--[[--------------------------< L A N G _ X X _ I N H E R I T >------------------------------------------------

Entry point for those {{lang-xx}} templates that call lang_xx_inherit().  Sets the initial style state to inherit.

]]

local function lang_xx_inherit (frame)
    local args = lang_xx_args_get (frame);

    initial_style_state = 'inherit';
    return _lang_xx (args);
end


--[[--------------------------< _ L A N G _ X X _ I N H E R I T >----------------------------------------------

Entry point from another module.  Sets the initial style state to inherit.

]]

local function _lang_xx_inherit (args)
    initial_style_state = 'inherit';
    return _lang_xx (args);
end


--[[--------------------------< _ I S _ I E T F _ T A G >------------------------------------------------------

Returns true when a language name associated with IETF language tag exists; nil else.  IETF language tag must be valid.

All code combinations supported by {{lang}} and the {{lang-xx}} templates are supported by this function.

Module entry point from another module

]]

local function _is_ietf_tag (tag)                                                -- entry point when this module is require()d into another
    local c, s, r, v, p, err;                                                    -- code, script, region, variant, private, error message
    c, s, r, v, p, err = get_ietf_parts (tag);                                    -- disassemble tag into constituent part and validate

    return ((c and not err) and true) or nil;                                    -- return true when code portion has a value without error message; nil else
end


--[[--------------------------< I S _ I E T F _ T A G >--------------------------------------------------------

Module entry point from an {{#invoke:}}

]]

local function is_ietf_tag (frame)
    return _is_ietf_tag (getArgs (frame)[1]);                                    -- args[1] is the ietf language tag to be tested; also get parent frame
end


--[[--------------------------< I S _ I E T F _ T A G _ F R A M E >--------------------------------------------

Module entry point from an {{#invoke:}}; same as is_ietf_tag() except does not get parameters from the parent
(template) frame.  This function not useful when called by {{lang|fn=is_ietf_tag_frame|<tag>}} because <tag>
is in the parent frame.

]]

local function is_ietf_tag_frame (frame)
    return _is_ietf_tag (getArgs (frame, {frameOnly = true,})[1]);                -- args[1] is the ietf language tag to be tested; do not get parent frame
end


--[[--------------------------< _ N A M E _ F R O M _ T A G >--------------------------------------------------

Returns language name associated with IETF language tag if valid; error message else.

All code combinations supported by {{lang}} and the {{lang-xx}} templates are supported by this function.

Set invoke's |link= parameter to yes to get wikilinked version of the language name.

Module entry point from another module

]]

local function _name_from_tag (args)
    local subtags = {};                                                            -- IETF subtags script, region, variant, and private
    local raw_code = args[1];                                                    -- save a copy of the input IETF subtag
    local link = 'yes' == args['link'];                                            -- make a boolean
    local label = args.label;
    local code;                                                                    -- the language code
    local msg;                                                                    -- gets an error message if IETF language tag is malformed or invalid
    local language_name = '';
   
    code, subtags.script, subtags.region, subtags.variant, subtags.private, msg = get_ietf_parts (raw_code);
    if msg then
        local template = (args['template'] and table.concat ({'{{', args['template'], '}}: '})) or '';    -- make template name (if provided by the template)
        return table.concat ({'<span style=\"font-size: 100%; font-style: normal;\" class=\"error\">Error: ', template, msg, '</span>'});
    end

    raw_code = format_ietf_tag (code, subtags.script, subtags.region, subtags.variant, subtags.private);    -- format to recommended subtag styles; private omitted because private
    language_name = language_name_get (raw_code, code);                            -- get language name; try ietf tag first, then code w/o variant then code w/ variant

    language_name = language_name:gsub ('%s+%b()', '');                            -- remove IANA parenthetical disambiguators or qualifiers from names that have them

    if link then                                                                -- when |link=yes, wikilink the language name
        if language_name:find ('languages') then
            language_name = make_wikilink (language_name, label);                -- collective language name uses simple wikilink
        elseif lang_data.article_name[code] then
            language_name = make_wikilink (lang_data.article_name[code][1], label or language_name);    -- language name with wikilink from override data
        else
            language_name = make_wikilink (language_name .. ' language', label or language_name);    -- language name with wikilink
        end
    end

    return language_name;
end


--[[--------------------------< N A M E _ F R O M _ T A G >----------------------------------------------------

Module entry point from an {{#invoke:}}

]]

local function name_from_tag (frame)                                            -- entry point from an {{#invoke:Lang|name_from_tag|<ietf tag>|link=<yes>|template=<template name>}}
    return _name_from_tag (getArgs(frame))                                        -- pass-on the args table, nothing else; getArgs() so we also get parent frame
end


--[[--------------------------< _ T A G _ F R O M _ N A M E >--------------------------------------------------

Returns the ietf language tag associated with the language name.  Spelling of language name must be correct
according to the spelling in the source tables.  When a standard language name has a parenthetical disambiguator,
that disambiguator must be omitted (they are not present in the data name-to-tag tables).

Module entry point from another module

]]

local function _tag_from_name (args)                                            -- entry point from another module
    local msg;

    if args[1] and '' ~= args[1] then
        local data = mw.loadData ('Module:Lang/tag from name');                    -- get the reversed data tables TODO: change when going live
        local lang = args[1]:lower();                                            -- allow any-case for the language name (speeling must till be correct)
        local tag = data.rev_override_table[lang] or data.rev_lang_table[lang] or data.rev_lang_dep_table[lang];    -- get the code; look first in the override then in the standard

        if tag then
            return tag, true;                                                    -- language name found so return tag and done; second return used by is_lang_name()
        else
            msg = 'language: ' .. args[1] .. ' not found'                        -- language name not found, error message
        end
    else
        msg = 'missing language name'                                            -- language name not provided, error message
    end

    local template = '';
    if args.template and '' ~= args.template then
        template = table.concat ({'{{', args['template'], '}}: '});                -- make template name (if provided by the template)
    end
    return table.concat ({'<span style=\"font-size: 100%; font-style: normal;\" class=\"error\">Error: ', template, msg, '</span>'});
end


--[[--------------------------< T A G _ F R O M _ N A M E >----------------------------------------------------

Module entry point from an {{#invoke:}}

]]

local function tag_from_name (frame)                                            -- entry point from an {{#invoke:Lang|tag_from_name|<language name>|link=<yes>|template=<template name>}}
    local result, _ = _tag_from_name (getArgs(frame))                            -- pass-on the args table, nothing else; getArgs() so we also get parent frame; supress second return used by is_lang_name()
    return result;       
end


--[[--------------------------< I S _ L A N G _ N A M E >------------------------------------------------------

Module entry point from an {{#invoke:}}

]]

local function is_lang_name (frame)
    local _, result = _tag_from_name (getArgs(frame))                            -- pass-on the args table, nothing else; getArgs() so we also get parent frame; supress second return used by tag_from_name()
    return result and true or nil;       
end


--[[--------------------------< _ T R A N S L >----------------------------------------------------------------

Module entry point from another module

]]

local function _transl (args)
    local title_table = lang_data.translit_title_table;                            -- table of transliteration standards and the language codes and scripts that apply to those standards
    local language_name;                                                        -- language name that matches language code; used for tool tip
    local translit;                                                                -- transliterated text to display
    local script;                                                                -- IANA script
    local msg;                                                                    -- for when called functions return an error message

    if is_set (args[3]) then                                                    -- [3] set when {{transl|code|standard|text}}
        args.text = args[3];                                                    -- get the transliterated text
        args.translit_std = args[2] and args[2]:lower();                        -- get the standard; lower case for table indexing

        if not title_table[args.translit_std] then
            return make_error_msg (table.concat ({'unrecognized transliteration standard: ', args.translit_std}), args, 'Transl');
        end
    else
        if is_set (args[2]) then                                                -- [2] set when {{transl|code|text}}
            args.text = args[2];                                                -- get the transliterated text
        else
            if args[1] and args[1]:match ('^%a%a%a?%a?$') then                    -- args[2] missing; is args[1] a code or its it the transliterated text?
                return make_error_msg ('no text', args, 'Transl');                -- args[1] is a code so we're missing text
            else
                args.text = args[1];                                            -- args[1] is not a code so we're missing that; assign args.text for error message
                return make_error_msg ('missing language / script code', args, 'Transl');
            end
        end
    end

    if is_set (args[1]) then                                                    -- IANA language code used for html lang= attribute; or ISO 15924 script code
        if args[1]:match ('^%a%a%a?%a?$') then                                    -- args[1] has correct form?
            args.code = args[1]:lower();                                        -- use the language/script code; only (2, 3, or 4 alpha characters); lower case because table indexes are lower case
        else
            return make_error_msg (table.concat ({'unrecognized language / script code: ', args[1]}), args, 'Transl');    -- invalid language / script code
        end
    else
        return make_error_msg ('missing language / script code', args, 'Transl');    -- missing language / script code so quit
    end

    args.italic, msg = validate_italic (args);
    if msg then
        return make_error_msg (msg, args, 'Transl');
    end
   
    if 'italic' == args.italic then                                                -- 'italic' when |italic=yes; because that is same as absent or not set and |italic=default
        args.italic = nil;                                                        -- set to nil;
    end

    if override_table[args.code] then                                            -- is code a language code defined in the override table?
        language_name = override_table[args.code][1];
    elseif lang_table[args.code] then                                            -- is code a language code defined in the standard language code tables?
        language_name = lang_table[args.code][1];
    elseif lang_dep_table[args.code] then                                        -- is code a language code defined in the deprecated language code tables?
        language_name = lang_dep_table[args.code][1];
    elseif script_table[args.code] then                                            -- if here, code is not a language code; is it a script code?
        language_name = script_table[args.code][1];
        script = args.code;                                                        -- code was an ISO 15924 script so use that instead
        args.code = '';                                                            -- unset because not a language code
    else
        return make_error_msg (table.concat ({'unrecognized language / script code: ', args.code}), args, 'Transl');    -- invalid language / script code
    end
                                                                                -- here only when all parameters passed to make_translit() are valid
    return make_translit (args.code, language_name, args.text, args.translit_std, script, args.italic);
end


--[[--------------------------< T R A N S L >------------------------------------------------------------------

Module entry point from an {{#invoke:}}

]]

local function transl (frame)
    return _transl (getArgs(frame));
end


--[[--------------------------< C A T E G O R Y _ F R O M _ T A G >--------------------------------------------

Returns category name associated with IETF language tag if valid; error message else

All code combinations supported by {{lang}} and the {{lang-xx}} templates are supported by this function.

Module entry point from another module

]]

local function _category_from_tag (args)
    local subtags = {};                                                            -- IETF subtags script, region, variant, and private
    local raw_code = args[1];                                                    -- save a copy of the input IETF subtag
    local link = 'yes' == args['link'];                                            -- make a boolean
    local label = args.label;
    local code;                                                                    -- the language code
    local msg;                                                                    -- gets an error message if IETF language tag is malformed or invalid
    local category_name = '';
   
    code, subtags.script, subtags.region, subtags.variant, subtags.private, msg = get_ietf_parts (raw_code);
    if msg then
        local template = (args['template'] and table.concat ({'{{', args['template'], '}}: '})) or '';    -- make template name (if provided by the template)
        return table.concat ({'<span style=\"font-size: 100%; font-style: normal;\" class=\"error\">Error: ', template, msg, '</span>'});
    end

    raw_code = format_ietf_tag (code, subtags.script, subtags.region, subtags.variant, subtags.private);    -- format to recommended subtag styles; private omitted because private
    category_name = language_name_get (raw_code, code);                            -- get language name; try ietf tag first, then code w/o variant then code w/ variant
    category_name = make_category (code, category_name, nil, true):gsub ('[%[%]]', '');

    return category_name;
end


--[[--------------------------< C A T E G O R Y _ F R O M _ T A G >--------------------------------------------

Module entry point from an {{#invoke:}}

]]

local function category_from_tag (frame)                                        -- entry point from an {{#invoke:Lang|category_from_tag|<ietf tag>|template=<template name>}}
    return _category_from_tag (getArgs (frame));                                -- pass-on the args table, nothing else; getArgs() so we also get parent frame
end


--[[--------------------------< E X P O R T E D   F U N C T I O N S >------------------------------------------
]]

return {
    category_from_tag = category_from_tag,
    lang = lang,                                                                -- entry point for {{lang}}
    lang_xx_inherit = lang_xx_inherit,                                            -- entry points for {{lang-??}}
    lang_xx_italic = lang_xx_italic,
    is_ietf_tag = is_ietf_tag,
    is_ietf_tag_frame = is_ietf_tag_frame,
    is_lang_name = is_lang_name,
    tag_from_name = tag_from_name,                                                -- returns ietf tag associated with language name
    name_from_tag = name_from_tag,                                                -- used for template documentation; possible use in ISO 639 name from code templates
    transl = transl,                                                            -- entry point for {{transl}}
   
    _category_from_tag = _category_from_tag,                                    -- entry points when this module is require()d into other modules
    _lang = _lang,
    _lang_xx_inherit = _lang_xx_inherit,
    _lang_xx_italic = _lang_xx_italic,
    _is_ietf_tag = _is_ietf_tag,
    get_ietf_parts = get_ietf_parts,
    _tag_from_name = _tag_from_name,
    _name_from_tag = _name_from_tag,
    _transl = _transl,
    };