Editing Module:Format TemplateData

local TemplateData = { serial = "2017-11-06",
                       suite  = "TemplateData" }
local plaintext = require("Module:Plain text")
--[=[
improve template:TemplateData
]=]
local Config = {
    -- multiple #invoke option names mapped into unique internal fields
    cat            = "strange",
    classNoNumTOC  = "suppressTOCnum",
--  classParams    = "classTable",
    cssParams      = "stylesTable",
    cssParWrap     = "stylesTabWrap",
    debug          = false,
    docpageCreate  = "suffix",
    docpageDetect  = "subpage",
    msgDescMiss    = "solo",
--  classTable     = false,    -- class for params table
    loudly         = false,    -- show exported element, etc.
    solo           = false,    -- complaint on missing description
    strange        = false,    -- title of maintenance category
    stylesTable    = false,    -- styles for params table
    stylesTabWrap  = false,    -- styles for params table wrapper
    subpage        = false,    -- pattern to identify subpage
    suffix         = false,     -- subpage creation scheme
    suppressTOCnum = false    -- class for TOC number suppression
}
local Data = {
    div     = false,    -- <div class="mw-templatedata-doc-wrap">
    got     = false,    -- table, initial templatedata object
    heirs   = false,    -- table, params that are inherited
    less    = false,    -- main description missing
    lasting = false,    -- old syntax encountered
    lazy    = false,    -- doc mode; do not generate effective <templatedata>
    leading = false,    -- show TOC
--  low     = false,    -- 1= mode
    order   = false,    -- parameter sequence
    params  = false,    -- table, exported parameters
    scream  = false,    -- error messages
    slang   = false,    -- project language code
    slim    = false,    -- JSON reduced to plain
    source  = false,    -- JSON input
    strip   = false,    -- <templatedata> evaluation
    tag     = false,    -- table, exported root element
    title   = false,    -- page
    tree    = false     -- table, rewritten templatedata object
}
local Permit = {
    styles  = { required    = "border-left: 3px solid black;",
                suggested   = "border-left: 3px solid #888;",
                optional    = "border-left: 3px solid #ccc",
                deprecated  = "border-left: 3px dotted red; background-color: #FDD;",
                tableheadbg = "background-color: #B3B7FF;" },
    params  = { aliases     = "table",
                autovalue   = "string",
                default     = "string table I18N nowiki",
                deprecated  = "boolean string",
                description = "string table I18N",
                example     = "string table I18N nowiki",
                label       = "string table I18N",
                inherits    = "string",
                required    = "boolean",
                suggested   = "boolean",
                suggestedvalues = "table",
                type        = "string" },
    root    = { description = "string table I18N",
                format      = "string",
                maps        = "table",
                params      = "table",
                paramOrder  = "table",
                sets        = "table" },
    search  = "[{,]%%s*(['\"])%s%%1%%s*:%%s*%%{",
    types   = { boolean                   = true,
                content                   = true,
                date                      = true,
                line                      = true,
                number                    = true,
                string                    = true,
                unknown                   = true,
                url                       = true,
                ["wiki-file-name"]        = true,
                ["wiki-page-name"]        = true,
                ["wiki-template-name"]    = true,
                ["wiki-user-name"]        = true,
                ["unbalanced-wikitext"]   = true,
                ["string/line"]           = "line",
                ["string/wiki-page-name"] = "wiki-page-name",
                ["string/wiki-user-name"] = "wiki-user-name" }
}

--
-- Generic utility functions
--

local function Fault( alert )
    -- Memorize error message
    -- Parameter:
    --     alert  -- string, error message
    if Data.scream then
        Data.scream = string.format( "%s *** %s", Data.scream, alert )
    else
        Data.scream = alert
    end
end -- Fault()

local function collapseWhitespace ( a )
	-- Collapses whitespace, HTML style.
    return a:gsub( "%s*\n%s*", " " )
            :gsub( "%s%s+", " " )
end -- collapseWhitespace

--------------------------------------------------------------------------------
--

local function facet( ask, at )
    -- Find physical position of parameter definition in JSON
    -- Parameter:
    --     ask  -- string, parameter name
    --     at   -- number, physical position within definition
    -- Returns number, or nil
    local seek = string.format( Permit.search,
                                ask:gsub( "%%", "%%%%" )
                                   :gsub( "([%-.()+*?^$%[%]])",
                                          "%%%1" ) )
    local i, k = Data.source:find( seek, at )
    local r, slice, source
    while i  and  not r do
        source = Data.source:sub( k + 1 )
        slice  = source:match( "^%s*\"([^\"]+)\"s*:" )
        if not slice then
            slice = source:match( "^%s*'([^']+)'%s*:" )
        end
        if ( slice and Permit.params[ slice ] )   or
           source:match( "^%s*%}" ) then
            r = k
        else
            i, k = Data.source:find( seek, k )
        end
    end    -- while i
    return r
end -- facet()



local function getLocalizedText( adapt )
    -- Retrieve localized text from system message
    -- Parameter:
    --     adapt  -- string, message ID after "templatedata-"
    -- Returns string, with localized text
    return mw.message.new( "templatedata-" .. adapt ):plain()
end -- getLocalizedText()



local function faculty( adjust )
    -- Test template arg for boolean
    --     adjust  -- string or nil
    -- Returns boolean
    local s = type( adjust )
    local r
    if s == "string" then
        r = mw.text.trim( adjust )
        r = ( r ~= ""  and  r ~= "0" )
    elseif s == "boolean" then
        r = adjust
    else
        r = false
    end
    return r
end -- faculty()



local function failures()
    -- Retrieve error collection and category
    -- Returns string
    local r
    if Data.scream then
        local e = mw.html.create( "span" )
                         :addClass( "error" )
                         :wikitext( Data.scream )
        r = tostring( e )
        mw.addWarning( "'''TemplateData'''<br />" .. Data.scream )
        if Config.strange then
            r = string.format( "%s[[category:%s]]",
                               r,
                               Config.strange )
        end
    else
        r = ""
    end
    return r
end -- failures()



local function handleNoexportWhitespace( adjust )
    -- Reduces runs of spaces, including newlines, to a single space, so the
    -- whole string is on one line. <noexport> blocks are left alone, but the
    -- <noexport> tags themselves are removed.
    --     adjust  -- string
    -- Returns string, with adjusted text
    local r
    if adjust:find( "<noexport>", 1, true ) then
        local i    = 1
        local j, k = adjust:find( "<noexport>", i, true )
        r = ""
        while j do
            if j > 1 then
                r = r .. collapseWhitespace( adjust:sub( i,  j - 1 ) )
            end
            i = k + 1
            j, k = adjust:find( "</noexport>", i, true )
            if j then
                r    = r .. adjust:sub( i,  j - 1 )
                i    = k + 1
                j, k = adjust:find( "<noexport>", i, true )
            else
                Fault( "missing </noexport>" )
            end
        end    -- while j
        r = r .. adjust:sub( i )
    else
        r = collapseWhitespace( adjust )
    end
    return r
end -- handleNoexportWhitespace()



local function faraway( alternatives )
    -- Retrieve project language version from multilingual text
    -- Parameter:
    --     alternatives  -- table, to be evaluated
    -- Returns
    --     1  -- string, with best match
    --     2  -- table of other versions, if any
    local n = 0
    local variants = { }
    local r1, r2
    if not Data.slang then
        Data.slang = mw.language.getContentLanguage():getCode()
    end
    for k, v in pairs( alternatives ) do
        if type( v ) == "string" then
            v = mw.text.trim( v )
            if v ~= "" then
                variants[ k ] = v
                n             = n + 1
            end
        end
    end -- for k, v
    if n > 0 then
        for k, v in pairs( variants ) do
            if v then
                if n == 1 then
                    r1 = v
                elseif k:lower() == Data.slang then
                    variants[ k ] = nil
                    r1 = v
                    r2 = variants
                    break -- for k, v
                end
            end
        end -- for k, v
        if not r1 then
            local seek = string.format( "^%s-", Data.slang )
            for k, v in pairs( variants ) do
                if v and k:lower():match( seek ) then
                    variants[ k ] = nil
                    r1 = v
                    r2 = variants
                    break -- for k, v
                end
            end -- for k, v
            if not r1 then
                local others = mw.language.getFallbacksFor( slang )
                table.insert( others, "en" )
                for i = 1, #others do
                    seek = others[ i ]
                    if variants[ seek ] then
                        r1                   = variants[ seek ]
                        variants[ seek ] = nil
                        r2                   = variants
                        break    -- for i
                    end
                end -- i = 1, #others
            end
            if not r1 then
                for k, v in pairs( variants ) do
                    if v then
                        variants[ k ] = nil
                        r1 = v
                        r2 = variants
                        break -- for k, v
                    end
                end -- for k, v
            end
        end
        if r2 then
            for k, v in pairs( r2 ) do
                if v then
                	local baseCode = k:match( "^%s*(%a%a%a?)-?%a*%s*$" )
                	if not baseCode or not mw.language.isKnownLanguageTag( baseCode ) then
                    	Fault( string.format( "Invalid <code>lang=%s</code>", k ))
                    end
                end
            end -- for k, v
        end
    end
    return r1, r2
end -- faraway()



local function fathers()
    -- Merge params with inherited values
    local n = 0
    local p = Data.params
    local t = Data.tree.params
    local p2, t2
    for k, v in pairs( Data.heirs ) do
        n = n + 1
    end -- for k, v
    for i = 1, n do
        for k, v in pairs( Data.heirs ) do
            if v  and  not Data.heirs[ v ] then
                n               = n - 1
                t[ k ].inherits = nil
                Data.heirs[ k ] = nil
                p2              = { }
                t2              = { }
                for k2, v2 in pairs( p[ v ] ) do
                    p2[ k2 ] = v2
                end -- for k2, v2
                if p[ k ] then
                    for k2, v2 in pairs( p[ k ] ) do
                        if type( v2 ) ~= "nil" then
                            p2[ k2 ] = v2
                        end
                    end -- for k2, v2
                end
                p[ k ] = p2
                for k2, v2 in pairs( t[ v ] ) do
                    t2[ k2 ] = v2
                end -- for k2, v2
                for k2, v2 in pairs( t[ k ] ) do
                    if type( v2 ) ~= "nil" then
                        t2[ k2 ] = v2
                    end
                end -- for k2, v2
                t[ k ] = t2
            end
        end -- for k, v
    end -- i = 1, n
    if n > 0 then
        local s
        for k, v in pairs( Data.heirs ) do
            if v then
                if s then
                    s = string.format( "%s &#124; %s", s, k )
                else
                    s = "Circular inherits: " .. k
                end
            end
        end -- for k, v
        Fault( s )
    end
end -- fathers()



local function feasible( about, asked )
    -- Create description head
    -- Parameter:
    --     about  -- table, supposed to contain description
    --     asked  -- true, if mandatory description
    -- Returns <block>, with head, or nil
    local para = mw.html.create( "div" )
    local plus, r
    if about and about.description then
        if type( about.description ) == "string" then
            para:wikitext( about.description )
        else
            para:wikitext( about.description[ 1 ] )
            plus = mw.html.create( "ul" )
            if not Config.loudly then
                plus:addClass( "templatedata-maintain" )
                    :css( "display", "none" )
            end
            for k, v in pairs( about.description[ 2 ] ) do
                plus:node( mw.html.create( "li" )
                                  :node( mw.html.create( "code" )
                                                :wikitext( k ) )
                                  :node( mw.html.create( "br" ) )
                                  :wikitext( handleNoexportWhitespace( v ) ) )
            end -- for k, v
        end
    elseif Config.solo and asked then
        para:addClass( "error" )
            :wikitext( Config.solo )
        Data.less = true
    else
        para = false
    end
    if para then
        if plus then
            r = mw.html.create( "div" )
                       :node( para )
                       :node( plus )
        else
            r = para
        end
    end
    return r
end -- feasible()



local function feat()
    -- Check and store parameter sequence
    if Data.source then
        local i = 0
        local s
        for k, v in pairs( Data.tree.params ) do
            if i == 0 then
                Data.order = { }
                i = 1
                s = k
            else
                i = 2
                break -- for k, v
            end
        end -- for k, v
        if i > 1 then
            local pointers = { }
            local points   = { }
            for k, v in pairs( Data.tree.params ) do
                i = facet( k, 1 )
                if i then
                    table.insert( points, i )
                    pointers[ i ] = k
                    i = facet( k, i )
                    if i then
                        s = "Parameter '%s' detected twice"
                        Fault( string.format( s, k ) )
                    end
                else
                    s = "Parameter '%s' not detected"
                    Fault( string.format( s, k ) )
                end
            end -- for k, v
            table.sort( points )
            for i = 1, #points do
                table.insert( Data.order,  pointers[ points[ i ] ] )
            end -- i = 1, #points
        elseif s then
            table.insert( Data.order, s )
        end
    end
end -- feat()



local function feature( access )
    -- Create table row for parameter, check and display violations
    -- Parameter:
    --     access  -- string, with name
    -- Returns <tr>
    local mode, s, status
    local fine    = function ( a )
                        s = mw.text.trim( a )
                        return a == s  and
                               a ~= ""  and
                               not a:find( "%|=\n" )  and
                               not a:find( "%s%s" )
                    end
    local begin   = mw.html.create( "td" )
    local code    = mw.html.create( "code" )
    local desc    = mw.html.create( "td" )
    local legal   = true
    local param   = Data.tree.params[ access ]
    local ranking = { "required", "suggested", "optional", "deprecated" }
    local r       = mw.html.create( "tr" )
    local sort, typed

    for k, v in pairs( param ) do
        if v == "" then
            param[ k ] = false
        end
    end -- for k, v

    -- label
    sort = param.label or access
    if sort:match( "^%d+$" ) then
        begin:attr( "data-sort-value",
                    string.format( "%05d", tonumber( sort ) ) )
    end
    begin:css( "font-weight", "bold" )
         :wikitext( sort )

    -- name and aliases
    code:css( "font-size", "92%" )
        :css( "white-space", "nowrap" )
        :wikitext( access )
    if not fine( access ) then
        code:addClass( "error" )
        Fault( string.format( "Bad ID params.<code>%s</code>", access ) )
        legal = false
        begin:attr( "data-sort-value",  " " .. sort )
    end
    code = mw.html.create( "td" )
                  :node( code )
    if access:match( "^%d+$" ) then
        code:attr( "data-sort-value",
                   string.format( "%05d", tonumber( access ) ) )
    end
    if type( param.aliases ) == "table" then
        local lapsus
        for k, v in pairs( param.aliases ) do
            code:tag( "br" )
            if type( v ) == "string" then
                if not fine( v ) then
                    lapsus = true
                    code:node( mw.html.create( "span" )
                                      :addClass( "error" )
                                      :css( "font-style", "italic" )
                                      :wikitext( "string" ) )
                end
                code:wikitext( s )
            else
                lapsus = true
                code:node( mw.html.create( "code" )
                                  :addClass( "error" )
                                  :wikitext( type( v ) ) )
            end
        end -- for k, v
        if lapsus then
            s = string.format( "params.<code>%s</code>.aliases", access )
            Fault(  getLocalizedText( "invalid-value" ):gsub( "$1", s )  )
            legal = false
        end
    end

    -- description etc.
    s = feasible( param )
    if s then
        desc:node( s )
    end
    if param.suggestedvalues or param.default or param.example or param.autovalue then
        local details = { "suggestedvalues", "default", "example", "autovalue" }
        local dl      = mw.html.create( "dl" )
        local dd, section, show, sv
        for i = 1, #details do
            s    = details[ i ]
            show = param[ s ]
            if show then
                section = getLocalizedText( "doc-param-" .. s )
                dt      = mw.html.create( "dt" ):wikitext( section )
                dd      = mw.html.create( "dd" )
                if type( show ) == "string" and (string.len(show) < 80) then
                	dt:cssText("float: left;margin-right: 1.6em;")
                end
                if param.type == "boolean" then
                    if (type( show ) == "table") then
                        -- "suggestedvalues"
                        for i = 1, #show do
                            sv = show[ i ]
                            if i > 1 then
                                dd:wikitext("&#10;")
                            end
                            if sv == "0" then
                                dd:wikitext("<span style=\"color: #610; font-weight: bold;\">False</span> (<code>0</code>)")
                            elseif sv == "1" then
                                dd:wikitext("<span style=\"color: #050; font-weight: bold;\">True</span> (<code>1</code>)")
                            else
                                dd:tag("code"):wikitext( sv )
                            end
                        end
                    elseif show == "0" then
                        dd:wikitext("<span style=\"color: #610; font-weight: bold;\">False</span> (<code>0</code>)")
                    elseif show == "1" then
                        dd:wikitext("<span style=\"color: #050; font-weight: bold;\">True</span> (<code>1</code>)")
                    else
                        dd:wikitext( show )
                    end
                elseif type( show ) == "table" then
                    -- "suggestedvalues"
                    for i = 1, #show do
                        sv = show[ i ]
                        if i > 1 then
                            dd:wikitext("&#10;")
                        end
                        dd:tag("code"):wikitext( sv )
                    end
                else
                    dd:wikitext( show )
                end
                dl:node( dt )
                  :node( dd )
            end
        end -- i = 1, #details
        desc:node( dl )
    end

    -- type
    if param.type then
        s     = Permit.types[ param.type ]
        typed = mw.html.create( "td" )
        if s then
            if type( s ) == "string" then
                Data.params[ access ].type = s
                typed:wikitext( getLocalizedText( "doc-param-type-" .. s ) )
                     :tag( "br" )
                typed:node( mw.html.create( "span" )
                                   :addClass( "error" )
                                   :wikitext( param.type ) )
                Data.lasting = true
            else
                s = getLocalizedText( "doc-param-type-" .. param.type )
                typed:wikitext( s )
            end
        else
            Data.params[ access ].type = "unknown"
            typed:addClass( "error" )
                 :wikitext( "INVALID" )
            s = string.format( "params.<code>%s</code>.type", access )
            Fault(  getLocalizedText( "invalid-value" ):gsub( "$1", s )  )
            legal = false
        end
    else
        typed = mw.html.create( "td" )
                   :wikitext( getLocalizedText( "doc-param-type-unknown" ) )
    end

    -- status
    if param.required then
        mode = 1
        if param.deprecated then
            Fault( string.format( "Required deprecated <code>%s</code>",
                                  access ) )
            legal = false
        end
    elseif param.deprecated then
        mode = 4
    elseif param.suggested then
        mode = 2
    else
        mode = 3
    end
    status = ranking[ mode ]
    ranking = getLocalizedText( "doc-param-status-" .. status )
    if mode == 1  or  mode == 4 then
        ranking = mw.html.create( "span" )
                         :css( "font-weight", "bold" )
                         :wikitext( ranking )
        if type( param.deprecated ) == "string" then
            ranking:tag( "br" )
            ranking:wikitext( param.deprecated )
        end
    end

    -- <tr>
    r:attr( "id",  "templatedata:" .. mw.uri.anchorEncode( access ) )
     :cssText( Permit.styles[ status ] )
     :node( begin )
     :node( code )
     :node( desc )
     :node( typed )
     :node( mw.html.create( "td" )
                   :attr( "data-sort-value", tostring( mode ) )
                   :node( ranking ) )
     :newline()
    if not legal then
        r:css( "border", "#FF0000 3px solid" )
    end
    return r
end -- feature()



local function features()
    -- Create <table> for parameters
    -- Returns <table>, or nil
    local r
    if Data.tree and Data.tree.params then
        local style = Permit.styles.tableheadbg
        local tbl   = mw.html.create( "table" )
                             :addClass( "wikitable" )
        local tr    = mw.html.create( "tr" )
        feat()
        if Data.order  and  #Data.order > 1 then
            tbl:addClass( "sortable" )
        end
--      if Config.classTable then
--          tbl:addClass( Config.classTable )
--      end
        if Config.stylesTable then
            tbl:cssText( Config.stylesTable )
        end
        tr:node( mw.html.create( "th" )
                        :attr( "colspan", "2" )
                        :cssText( style )
                        :wikitext( getLocalizedText( "doc-param-name" ) ) )
          :node( mw.html.create( "th" )
                        :cssText( style )
                        :wikitext( getLocalizedText( "doc-param-desc" ) ) )
          :node( mw.html.create( "th" )
                        :cssText( style )
                        :wikitext( getLocalizedText( "doc-param-type" ) ) )
          :node( mw.html.create( "th" )
                        :cssText( style )
                        :wikitext( getLocalizedText( "doc-param-status" ) ) )
        tbl:newline()
--         :node( mw.html.create( "thead" )
                         :node( tr )
--             )
           :newline()
        if Data.order then
            for i = 1, #Data.order do
                tbl:node( feature( Data.order[ i ] ) )
            end -- for i = 1, #Data.order
        end
        if Config.stylesTabWrap then
            r = mw.html.create( "div" )
                   :cssText( Config.stylesTabWrap )
                   :node( tbl )
        else
            r = tbl
        end
    end
    return r
end -- features()



local function finalize()
    -- Wrap presentation into frame
    -- Returns string
    local r
    if Data.div then
        r = tostring( Data.div )
    elseif Data.strip then
        r = Data.strip
    else
        r = ""
    end
    return r .. failures()
end -- finalize()



local function find()
    -- Find JSON data within page source (title)
    -- Returns string, or nil
    local s = Data.title:getContent()
    local i, j = s:find( "<templatedata>", 1, true )
    local r
    if i then
        local k = s:find( "</templatedata>", j, true )
        if k then
           r = mw.text.trim( s:sub( j + 1,  k - 1 ) )
        end
    end
    return r
end -- find()



local function flat( adjust )
    -- Remove formatting from text string
    -- Parameter:
    --     arglist  -- string, to be stripped, or nil
    -- Returns string, or nil
    local r
    if adjust then
        r = adjust:gsub( "\n", " " )
        if r:find( "<noexport>", 1, true ) then
            r = r:gsub( "<noexport>(.*)</noexport>", "" )
        end
        r = plaintext._main(r)
        if r:find( "&", 1, true ) then
            r = mw.text.decode( r )
        end
    end
    return r
end -- flat()



local function flush()
    -- JSON encode narrowed input; obey unnamed (numerical) parameters
    -- Returns <templatedata> JSON string
    local r
    if Data.tag then
        r = mw.text.jsonEncode( Data.tag ):gsub( "%}$", "," )
    else
        r = "{"
    end
    r = r .. "\n\"params\":{"
    if Data.order then
        local sep = ""
        local s
        for i = 1, #Data.order do
            s   = Data.order[ i ]
            r   = string.format( "%s%s\n%s:%s",
                                 r,
                                 sep,
                                 mw.text.jsonEncode( s ),
                                 mw.text.jsonEncode( Data.params[ s ] ) )
            sep = ",\n"
        end -- for i = 1, #Data.order
    end
    r = r .. "\n}\n}"
    return r
end -- flush()



local function focus( access )
    -- Check components; focus multilingual description, build trees
    -- Parameter:
    --     access  -- string, name of parameter, nil for root
    local f = function ( a, at )
                    local r
                    if at then
                        r = string.format( "<code>params.%s</code>", at )
                    else
                        r = "''root''"
                    end
                    if a then
                        r = string.format( "%s<code>.%s</code>", r, a )
                    end
                    return r
                end
    local parent
    if access then
        parent = Data.got.params[ access ]
    else
        parent = Data.got
    end
    if type( parent ) == "table" then
        local elem, got, permit, s, scope, slot, tag, target
        if access then
            permit = Permit.params
            if type( access ) == "number" then
                slot = tostring( access )
            else
                slot = access
            end
        else
            permit = Permit.root
        end
        for k, v in pairs( parent ) do
            scope = permit[ k ]
            if scope then
                s = type( v )
                if s == "string" then
                    v = mw.text.trim( v )
                end
                if scope:find( s, 1, true ) then
                    if scope:find( "I18N", 1, true ) then
                        if s == "string" then
                            elem = handleNoexportWhitespace( v )
                        else
                            local translated
                            v, translated = faraway( v )
                            if v then
                                if translated  and
                                   k == "description" then
                                    elem = { [ 1 ] = handleNoexportWhitespace( v ),
                                             [ 2 ] = translated }
                                else
                                    elem = handleNoexportWhitespace( v )
                                end
                            else
                                elem = false
                            end
                        end
                        if v then
                            if scope:find( "nowiki", 1, true ) then
                                elem = mw.text.nowiki( v )
                            else
                                v = flat( v )
                            end
                        end
                    else
                        if k == "params"  and  not access then
                            v    = nil
                            elem = nil
                        elseif k == "format"  and  not access then
                            v    = mw.text.decode( v )
                            elem = v
                        elseif k == "inherits" then
                            elem = v
                            if not Data.heirs then
                                Data.heirs = { }
                            end
                            Data.heirs[ slot ] = v
                            v                  = nil
                        elseif s == "string" then
                            v    = mw.text.nowiki( v )
                            elem = v
                        else
                            elem = v
                        end
                    end
                    if type( elem ) ~= "nil" then
                        if not target then
                             if access then
                                 if not Data.tree.params then
                                     Data.tree.params = { }
                                 end
                                 Data.tree.params[ slot ] = { }
                                 target = Data.tree.params[ slot ]
                             else
                                 Data.tree = { }
                                 target    = Data.tree
                             end
                        end
                        target[ k ] = elem
                        elem        = false
                    end
                    if type( v ) ~= "nil" then
                        if not tag then
                            if access then
                                if not Data.params then
                                    Data.params = { }
                                end
                                Data.params[ slot ] = { }
                                tag = Data.params[ slot ]
                            else
                                Data.tag = { }
                                tag      = Data.tag
                            end
                        end
                        tag[ k ] = v
                    end
                else
                    s = string.format( "Type <code>%s</code> bad for %s",
                                       scope,  f( k, slot ) )
                    Fault( s )
                end
            else
                Fault( "Unknown component " .. f( k, slot ) )
            end
        end -- for k, v
    else
        Fault( f() .. " needs to be of <code>object</code> type" )
    end
end -- focus()



local function format()
    -- Build presented documentation
    -- Returns <div>
    local r = mw.html.create( "div" )
    local s = feasible( Data.tree, true )
    if s then
        r:node( s )
    end
    if Data.leading then
        local toc = mw.html.create( "div" )
        if Config.suppressTOCnum then
            toc:addClass( Config.suppressTOCnum )
        end
        toc:css( "margin-top", "0.5em" )
           :wikitext( "__TOC__" )
        r:newline()
         :node( toc )
         :newline()
    end
    s = features()
    if s then
        if Data.leading then
            r:node( mw.html.create( "h2" )
                           :wikitext( getLocalizedText( "doc-params" ) ) )
             :newline()
        end
        r:node( s )
    end
    if Data.tree and Data.tree.format then
        local e, style
        s = Data.tree.format:lower( Data.tree.format )
        if s == "inline"  or  s == "block" then
            style = "i"
        else
            style = "code"
        end
        r:node( mw.html.create( "p" )
                       :wikitext( "Format: " )
                       :node( mw.html.create( style )
                                     :wikitext( s ) ) )
    end
    return r
end -- format()



local function free()
    -- Remove JSON comment lines
    Data.source:gsub( "([{,\"'])(%s*\n%s*//.*\n%s*)([},\"'])",
                      "%1%3" )
end -- free()



local function full()
    -- Build HTML table for display from JSON data, and append an invisible
    -- <templatedata> block.
    Data.div = mw.html.create( "div" )
                      :addClass( "mw-templatedata-doc-wrap" )
    focus()
    if Data.tag then
        if type( Data.got.params ) == "table" then
            for k, v in pairs( Data.got.params ) do
                focus( k )
            end -- for k, v
            if Data.heirs then
                fathers()
            end
        end
    end
    Data.div:node( format() )
    if not Data.lazy then
        Data.slim = flush()
        if TemplateData.frame then
            local div   = mw.html.create( "div" )
            local tdata = { [ 1 ] = "templatedata",
                            [ 2 ] = Data.slim }
            Data.strip = TemplateData.frame:callParserFunction( "#tag",
                                                                tdata )
            div:wikitext( Data.strip )
            if Config.loudly then
            	-- Display raw templatedata table all the time.
                Data.div:node( mw.html.create( "hr" ) )
                Data.div:node( div )
            else
            	-- Creates an expand link to check raw templatedata table.
            	local wrapper = mw.html.create( "div" )
                wrapper:addClass( "mw-collapsible" )
                wrapper:addClass( "mw-collapsed" )
                wrapper:css( "font-size", "85%" )
                div:addClass( "mw-collapsible-content" )
                wrapper:wikitext( "'''Test of raw TemplateData output''': " )
                wrapper:node( div )
                Data.div:node( wrapper )
            end
        end
    end
end -- full()



local function furnish( adapt, arglist )
    -- Called by f, this function is the first to do any real work when the
    -- module is invoked.
    -- Parameter:
    --     adapt    -- table, #invoke parameters
    --     arglist  -- table, template parameters
    -- Returns string
--local spy=""
    local source
    for k, v in pairs( Config ) do
        if adapt[ k ]  and  adapt[ k ] ~= "" then
            Config[ v ] = adapt[ k ]
        end
    end -- for k, v
    Config.loudly = faculty( arglist.debug or adapt.debug )
--if mw.site.server:find( "//de.wikipedia.beta.wmflabs.org", 1, true ) then
--    Config.loudly  = true
--end
    Data.lazy     = faculty( arglist.lazy )  and  not Config.loudly
    Data.leading  = faculty( arglist.TOC )
    if arglist.JSON then
        source = arglist.JSON
    elseif arglist[ 1 ] then
        local s     = mw.text.trim( arglist[ 1 ] )
        local start = s:sub( 1, 1 )
        if start == "<" then
            Data.strip = s
        elseif start == "{" then
            source = s
        elseif mw.ustring.sub( s, 1, 8 ) ==
               mw.ustring.char( 127, 39, 34, 96, 85, 78, 73, 81 ) then -- <DEL> ' " ` U N I Q
            Data.strip = s
        end
    end
    if not source then
        Data.title = mw.title.getCurrentTitle()
        source = find()
        if not source  and
           Config.subpage  and  Config.suffix  and
           not Data.title.text:match( Config.subpage ) then
            local s = string.format( Config.suffix,
                                     Data.title.prefixedText )
            Data.title = mw.title.new( s )
            if Data.title.exists then
                source = find()
            end
        end
--if source  and
--           ( source:find( "|", 1, true ) or
--             source:find( "}}", 1, true ) ) then
--                      --  <ref
--spy=string.format( "[[category:%s]]", Config.strange )
--end
    end
    if not Data.lazy  and  Config.subpage then
        if not Data.title then
            Data.title = mw.title.getCurrentTitle()
        end
        Data.lazy = Data.title.text:match( Config.subpage )
    end
    TemplateData.getPlainJSON( source )
    return finalize()
--return spy .. finalize()
end -- furnish()



TemplateData.failsafe = function ( assert )
	-- Checks the age of this implementation against some minimum ("assert").
    local r
    if not assert  or  assert <= TemplateData.serial then
        r = TemplateData.serial
    else
        r = false
    end
    return r
end -- TemplateData.failsafe()



TemplateData.getPlainJSON = function ( adapt )
    -- Reduce enhanced JSON data to plain text localized JSON
    -- Parameter:
    --     adapt  -- string, with enhanced JSON
    -- Returns string, or not
    if type( adapt ) == "string" then
        Data.source = adapt
        free()
        Data.got = mw.text.jsonDecode( Data.source )
        if Data.got then
            full()
            if Data.lasting then
                Fault( "deprecated type syntax" )
            end
            if Data.less then
                Fault( Config.solo )
            end
        elseif not Data.strip then
            Fault( "fatal JSON error" )
        end
    end
    return Data.slim
end -- TemplateData.getPlainJSON()



TemplateData.test = function ( adapt, arglist )
    TemplateData.frame = mw.getCurrentFrame()
    return furnish( adapt, arglist )
end -- TemplateData.test()



-- Export
local p = { }

p.f = function ( frame )
    -- The entry point for templates invoking the module.
    -- Just wraps furnish in an exception handler.
    local lucky, result
    TemplateData.frame = frame
    lucky, result = pcall( furnish, frame.args, frame:getParent().args )
    if not lucky then
        Fault( "INTERNAL: " .. result )
        result = failures()
    end
    return result
end -- p.f()

p.failsafe = function ( frame )
    -- Versioning interface
    local s = type( frame )
    local since
    if s == "table" then
        since = frame.args[ 1 ]
    elseif s == "string" then
        since = frame
    end
    if since then
        since = mw.text.trim( since )
        if since == "" then
            since = false
        end
    end
    return TemplateData.failsafe( since )  or  ""
end -- p.failsafe()

p.TemplateData = function ()
    -- Module interface
    return TemplateData
end

return p