Module:Format TemplateData

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Format TemplateData – Module with auxilary functions for template documentation, especially by TemplateData.

Core functionality is improved presentation on documentation pages.

Template:Anker Improve template documentation page – MediaWiki disappointing

For presentation of template depiction in VisualEditor agreement was made to abandon all markup and clickable links, permitting all tooltips in all environments. Basically this is reasonable, albeit tooltips with markup and clickable links are supported as HTML application for decades now and JavaScript is present anyway when VisualEditor is used.

• In consequence it was decided, that also presentation on template documentation views never ever is permitted to contain effective links or markup.
• That involved, that on many template documentation pages two separated parameter documentation tables are needed and required to be maintained simultaneously: One plain text version for VisualEditor, and a useful one for complex circumstances, with links and markup and lists and tables. – BTW, VisualEditor has not only tooltips, but also a static GUI view, where the lack of deepening links in parameter description is painful.

This state is indefensible.

Template:Anker Improved presentation

In addition to the simple syntax supported by MediaWiki and presented in the VisualEditor, the following features can be added to the JSON code for the template documentation page. They affect the elements classified as InterfaceText, but are only useful for description fields.

Wikilinks (internal format)

• Using double square brackets pages can be linked as common.
• In VisualEditor, only link title is visible, as it is displayed otherwise.

External links (URL format)

• Open URL are linked as usual by themselves. In VisualEditor they appear as normal text.
• External links enclosed in simple square brackets are displayed normally on the template documentation page. In VisualEditor the title is omitted and the URL is displayed so that the users can c&p it and transfer it to the address field of the browser. There is no other way.

Apostrophs ' for italic and bold

• They can be used to emphasize on the documentation page and are missing in VisualEditor (regular script).

HTML entities

• The following entities can be used: < > & "   and all numeric formats.

HTML tags

• HTML tags (and the MediaWiki elements that are not replaced in advance) are removed for the VisualEditor. Otherwise, they remain effective.
• Attributes are often included in ", which conflicts with the JSON syntax. It is important to make sure that ' is used, which can be a problem with template transclusions.

<noexport> … </noexport>

• The enclosed areas are not exported to the VisualEditor.
• More complex wiki syntax and extensive explanations can be restricted to the documentation page.
• Within a noexport area, the line structure of the source text is considered. Otherwise everything is running in a single line, as it would also be represented in the VisualEditor.

Templates

• In particular when the template parameter JSON= is used, templates can be distributed anywhere in the JSON code. However, the expanded syntax might collide with the JSON syntax.

More effects

• According to the state (required, suggested, optional, deprecated) the table rows are highlighted in light blue, white, gray and pale red.
• When sorting by state, this importance is taken into account and not the alphabetical sequence of the keywords.
• Each parameter can be addressed as a jump destination. The fragment is #templatedata:parameter-name.
• Missing labels are highlighted as errors.
• A maintenance category is triggered if errors occur.
• If there are no parameters, the element params:{} is not required.

Eliminate disadvantages

Two aspects were found to be particularly disturbing in 2013–2017:

1. Even if no parameters at all were defined, a table head is always displayed for a table without content. Even more, this is sortable.
   • A reduction was rejected with Template:Phab. A sortable table of the parameters would be always necessary, even if the table has no rows at all and consists only of the header row.
   • This ridiculous statement led to the development of this module in 2016.
2. Even if the context does not permit that default values or even AutoValue specifications will be defined ever, a content-free six-line definition list is output for each individual parameter value.
   • Template:Phab / Template:Phab / Template:Phab / Template:Phab
   • MediaWiki did not even deign to answer the disastrous documentation page situation.

The general comments show that MediaWiki only regards the presentation of TemplateData specifications in the VisualEditor as important. However, someone has to program and maintain the templates and someone needs to generate the template description and make it manageable beside the functionality in the VisualEditor form, but that is beyond ken.

• Two years later the relatively easy task Template:Phab has been solved by a community originated patch.

General workflow

• An attempt is made to read the JSON object (string) from passed template parameters.
• If this failed, the source code of the current and the documentation page is searched for <templatedata> elements.
• Two representations are obtained from the JSON object input:
  1. A localized version, markup etc. stripped off, in JSON format.
  2. An HTML structure, basically similar to the MediaWiki representation, possibly with table of the parameters, with enhanced features.
• The result of the template is a visible documentation with markup, followed by a hidden <templatedata> element. This is done for the export and corresponds to the MediaWiki guidelines.
  • If current page has been identified as documentation page the hidden <templatedata> is suppressed, and those pages do not appear separately in Special:PagesWithProp/templatedata.

Template:Anker Functions for templates

Details

f Template:Anker

Improve TemplateData-presentation; used in Template:Format TemplateData

Parameters of template transclusion environment (all optional):

1

JSON string or <templatedata> object

JSON

JSON string

(precedes 1)

Transition from <templatedata> objects with pipe symbols needs special attention: Pipes are to be represented as {{!}}, on double curly brackets one should be encoded by HTML entity.

TOC

1 – Insert table of contents after general purpose descriptions; but before parameter list, if present

Example

lang

Language code according to ISO 639 etc.

lazy

1 – Presentation only, do not generate an effective data block

For general method descriptions.

debug

1 – developer mode

source

1 – show effective JSON source text (after template expansion) for debugging

Parameters of #invoke for particular project adaption (all optional):

lang

Language code according to ISO 639 etc.

debug

Development mode, if provided and not equal 0

cat

Title of a maintenance category on invalid parameter value etc.

Deprecated – use configuration module

docpageCreate

Pattern for creation of subpage names; %s/Doku

Deprecated – use configuration module

docpageDetect

Pattern for recognition of subpage names; /Doku$

Deprecated – use configuration module

msgDescMiss

Localisation: complaint text on missing description

Deprecated – use configuration module

Returns: HTML code; and/or error message, probably with class="error"

failsafe Template:Anker

Version management

Template:Anker Functions for Lua modules (API)

Some functions described above can be used by other modules:

local lucky, TemplateData = pcall( require, "Module:Format TemplateData" )
if type( TemplateData ) == "table" then
    TemplateData = TemplateData.TemplateData()
else
    -- failure; TemplateData is the error message
    return "<span class='error'>" .. TemplateData .. "</span>"
end

TemplateData.failsafe(atleast)

1. atleast
   optional
   nil or minimal version request or "wikidata"

Returns: string or false

TemplateData.getPlainJSON(adapt)

Reduce enhanced JSON information to MediaWiki JSON

1. adapt
   string, with JSON (enhanced)

Returns: string, with JSON (MediaWiki )

TemplateData.test(adapt, arglist)

Simulation of template functionality

1. adapt
   table, #invoke parameters
2. arglist
   table, template parameters

Returns: string

Usage

Currently focussing on one template only:

• Template:Format TemplateData

Dependencies

• Multilingual
• Text
• WLink

Template:Anker Configuration

A local module Module:Format TemplateData/config, if present, facilitates adaptions to the local project.

A table is expected via mw.loadData. The following entries are optional components:

catProblem

Title of a maintenance category on invalid parameter value etc.

classNoNumTOC

Name of class for the table of contents; especially to suppress numbering.

nonumtoc

classTable

table with classes for the table of parameters.

{ "wikitable" }

cssParams

table with CSS assignments for formatting of single parameters

cssParWrap

table with CSS assignments for formatting of the entire parameter table

docpageCreate

Pattern for creation of subpage names; %s/Doku

%s/Doku

docpageDetect

Pattern for recognition of subpage names; /Doku$

/Doku$

help*********

Link targets for context sensitive help on details

helpBoolean

helpContent

helpDate

helpFile

helpFormat

Link target on help about wikitext transclusion layout

helpLine

helpNumber

helpPage

helpString

helpTemplate

helpURL

helpUser

msgDescMiss

Localisation: complaint text on missing description

permit

table with specification of properties for a single parameter; components:

boole

table with specification for boolean presentation

Two components true and false – each one table:

css

table with CSS for this explanation of the value

lead

true – show explanation for 0 or 1 respectively preceding the value

false – show explanation for 0 or 1 respectively following the value

show

explanation; string or false to suppress

css

table with specifications for rendering of the parameter table; components:

tablehead

table with CSS for table head

required

table with CSS for required

suggested

table with CSS for suggested

optional

table with CSS for optional

deprecated

table with CSS for deprecated

The above documentation is transcluded from Module:Format TemplateData/doc. (edit | history)
Editors can experiment in this module's sandbox (create | mirror) and testcases (create) pages.
Subpages of this module.

local TemplateData = { suite  = "TemplateData",
                       serial = "2022-03-10",
                       item   = 46997995 }
--[==[
improve template:TemplateData
]==]
local Failsafe = TemplateData


local Config = {
    -- multiple option names mapped into unique internal fields
    basicCnf = { catProblem          = "strange",
                 classMultiColumns   = "selMultClm",
                 classNoNumTOC       = "suppressTOCnum",
                 classTable          = "classTable",
                 cssParWrap          = "cssTabWrap",
                 cssParams           = "cssTable",
                 docpageCreate       = "suffix",
                 docpageDetect       = "subpage",
                 helpBoolean         = "support4boolean",
                 helpContent         = "support4content",
                 helpDate            = "support4date",
                 helpFile            = "support4wiki-file-name",
                 helpFormat          = "supportFormat",
                 helpLine            = "support4line",
                 helpNumber          = "support4number",
                 helpPage            = "support4wiki-page-name",
                 helpString          = "support4string",
                 helpTemplate        = "support4wiki-template-name",
                 helpURL             = "support4url",
                 helpUser            = "support4wiki-user-name",
                 msgDescMiss         = "solo",
                 tStylesTOCnum       = "stylesTOCnum",
                 tStylesMultiColumns = "stylesMultClm" },
    classTable     = { "wikitable" },    -- classes for params table
    debugmultilang = "C0C0C0",
    loudly         = false,    -- show exported element, etc.
    solo           = false,    -- complaint on missing description
    strange        = false,    -- title of maintenance category
    cssTable       = false,    -- styles for params table
    cssTabWrap     = false,    -- styles for params table wrapper
    debug          = false,
    subpage        = false,    -- pattern to identify subpage
    suffix         = false,    -- subpage creation scheme
    suppressTOCnum = false,    -- class for TOC number suppression
    jsonDebug      = "json-code-lint"    -- class for jsonDebug tool
}
local Data = {
    div     = false,    -- <div class="mw-templatedata-doc-wrap">
    got     = false,    -- table, initial templatedata object
    heirs   = false,    -- table, params that are inherited
    jump    = false,    -- source position at end of "params"
    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
    sibling = false,    -- TOC juxtaposed
    slang   = nil,      -- project/user 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 = {
    builder = { after           = "block",
                align           = "block",
                block           = "block",
                compressed      = "block",
                dense           = "block",
                grouped         = "inline",
                half            = "inline",
                indent          = "block",
                inline          = "inline",
                last            = "block",
                lead            = "block",
                newlines        = "*",
                spaced          = "inline" },
    colors  = { bg          = "FFFFFF",
                fg          = "000000",
                tableheadbg = "B3B7FF",
                required    = "EAF3FF",
                suggested   = "FFFFFF",
                optional    = "EAECF0",
                deprecated  = "FFCBCB" },
    params  = { aliases         = "table",
                autovalue       = "string",
                default         = "string table I18N nowiki",
                deprecated      = "boolean string I18N",
                description     = "string table I18N",
                example         = "string table I18N nowiki",
                label           = "string table I18N",
                inherits        = "string",
                required        = "boolean",
                style           = "string table",
                suggested       = "boolean",
                suggestedvalues = "string table number boolean",
                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" }
}



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 Fetch( ask, allow )
    -- Fetch module
    -- Parameter:
    --     ask    -- string, with name
    --                       "/global"
    --                       "Multilingual"
    --                       "Text"
    --                       "WLink"
    --     allow  -- true: no error if unavailable
    -- Returns table of module
    -- error: Module not available
    local sign = ask
    local r, stem
    if sign:sub( 1, 1 ) == "/" then
        sign = TemplateData.frame:getTitle() .. sign
    else
        stem = sign
        sign = "Module:" .. stem
    end
    if TemplateData.extern then
        r = TemplateData.extern[ sign ]
    else
        TemplateData.extern = { }
    end
    if not r then
        local lucky, g = pcall( require, sign )
        if type( g ) == "table" then
            if stem  and  type( g[ stem ] ) == "function" then
                r = g[ stem ]()
            else
                r = g
            end
            TemplateData.extern[ sign ] = r
        elseif not allow then
            error( string.format( "Fetch(%s) %s", sign, g ), 0 )
        end
    end
    return r
end -- Fetch()



local function Foreign()
    -- Guess human language
    -- Returns slang, or not
    if type( Data.slang ) == "nil" then
        local Multilingual = Fetch( "Multilingual", true )
        if Multilingual  and
           type( Multilingual.userLangCode ) == "function" then
            Data.slang = Multilingual.userLangCode()
        else
            Data.slang = mw.language.getContentLanguage():getCode()
                                                         :lower()
        end
    end
    if Data.slang  and
       mw.ustring.codepoint( Data.slang, 1, 1 ) > 122 then
        Data.slang = false
    end
    return Data.slang
end -- Foreign()



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, r, slice, source
    if not Data.jump then
        Data.jump = Data.source:find( "params", 2 )
        if Data.jump then
            Data.jump = Data.jump + 7
        else
            Data.jump = 1
        end
    end
    i, k = Data.source:find( seek,  at + Data.jump )
    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 facilities( apply )
    -- Retrieve details of suggestedvalues
    -- Parameter:
    --     apply  -- table, with plain or enhanced values
    --               .suggestedvalues  -- table|string|number, or more
    -- Returns
    --     1  -- table, with suggestedvalues
    --     2  -- table, with CSS map, or not
    --     3  -- string, with class, or not
    --     4  -- string, with templatestyles, or not
    local elements = apply.suggestedvalues
    local s        = type( elements )
    local r1, r2, r3, r4
    if s == "table" then
        local values = elements.values
        if type( values ) == "table" then
            r1 = values
            if type( elements.scroll ) == "string" then
                r2 = r2  or  { }
                r2.height   = apply.scroll
                r2.overflow = "auto"
            end
            if type( elements.minwidth ) == "string" then
                local s = type( elements.maxcolumns )
                r2 = r2  or  { }
                r2["column-width"] = elements.minwidth
                if s == "string"  or
                   s == "number" then
                    s = tostring( elements.maxcolumns )
                    r2["column-count"] = s
                end
                if type( Config.selMultClm ) == "string" then
                    r3 = Config.selMultClm
                end
                if type( Config.stylesMultClm ) == "string" then
                    local src = Config.stylesMultClm .. "/styles.css"
                    r4 = TemplateData.frame
                                     :extensionTag( "templatestyles",
                                                    nil,
                                                    { src = src } )
                end
            end
        elseif elements  and  elements ~= "" then
            r1 = elements
        end
    elseif s == "string" then
        s = mw.text.trim( about )
        if s ~= "" then
            r1 = { }
            table.insert( r1,
                          { code = s } )
        end
    elseif s == "number" then
        r1 = { }
        table.insert( r1,
                      { code = tostring( elements ) } )
    end
    return r1, r2, r3, r4
end -- facilities()



local function factory( adapt )
    -- Retrieve localized text from system message
    -- Parameter:
    --     adapt  -- string, message ID after "templatedata-"
    -- Returns string, with localized text
    local o = mw.message.new( "templatedata-" .. adapt )
    if Foreign() then
        o:inLanguage( Data.slang )
    end
    return o:plain()
end -- factory()



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 fair( adjust )
    -- Reduce text to one line of plain text, or noexport wikitext blocks
    --     adjust  -- string
    -- Returns string, with adjusted text
    local f    = function ( a )
                     return a:gsub( "%s*\n%s*", " " )
                             :gsub( "%s%s+", " " )
                 end
    local tags = { { start = "<noexport>",
                     stop  = "</noexport>" },
                   { start = "<exportonly>",
                     stop  = "</exportonly>",
                     l     = false }
                 }
    local r = adjust
    local i, j, k, s, tag
    for m = 1, 2 do
        tag = tags[ m ]
        if r:find( tag.start, 1, true ) then
            s     = r
            r     = ""
            i     = 1
            tag.l = true
            j, k  = s:find( tag.start, i, true )
            while j do
                if j > 1 then
                    r = r .. f( s:sub( i,  j - 1 ) )
                end
                i    = k + 1
                j, k = s:find( tag.stop, i, true )
                if j then
                    if m == 1 then
                        r = r .. s:sub( i,  j - 1 )
                    end
                    i    = k + 1
                    j, k = s:find( tag.start, i, true )
                else
                    Fault( "missing " .. tag.stop )
                end
            end    -- while j
            r = r .. s:sub( i )
        elseif m == 1 then
            r = f( r )
        end
    end -- for m
    if tags[ 2 ].l then
        r = r:gsub( "<exportonly>.*</exportonly>", "" )
    end
    return r
end -- fair()



local function fancy( advance, alert )
    -- Present JSON source
    -- Parameter:
    --     advance  -- true, for nice
    --     alert    -- true, for visible
    -- Returns string
    local r
    if Data.source then
        local support = Config.jsonDebug
        local css
        if advance then
            css = { height = "6em",
                    resize = "vertical" }
            r   = { [ 1 ] = "syntaxhighlight",
                    [ 2 ] = Data.source,
                    lang  = "json",
                    style = table.concat( css, ";" ) }
            if alert then
                r.class( support )
            end
            r = TemplateData.frame:callParserFunction( "#tag", r )
        else
            css = { [ "font-size" ]   = "77%",
                    [ "line-height" ] = "1.35" }
            if alert then
                css.resize = "vertical"
            else
                css.display = "none"
            end
            r = mw.html.create( "pre" )
                       :addClass( support )
                       :css( css )
                       :wikitext( mw.text.encode( Data.source ) )
            r = tostring( r )
        end
        r = "\n".. r
    else
        r = ""
    end
    return r
end -- fancy()



local function faraway( alternatives )
    -- Retrieve best 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
    for k, v in pairs( alternatives ) do
        if type( v ) == "string" then
            v = mw.text.trim( v )
            if v ~= ""  and  type( k ) == "string" then
                k = k:lower()
                variants[ k ] = v
                n             = n + 1
            end
        end
    end -- for k, v
    if n > 0 then
        local Multilingual = Fetch( "Multilingual", true )
        if Multilingual  and
           type( Multilingual.i18n ) == "function" then
            local show, slang = Multilingual.i18n( variants )
            if show then
                r1 = show
                variants[ slang ] = nil
                r2 = variants
            end
        end
        if not r1 then
            Foreign()
            for k, v in pairs( variants ) do
                if n == 1 then
                    r1 = v
                elseif Data.slang == k then
                    variants[ k ] = nil
                    r1 = v
                    r2 = variants
                end
            end -- for k, v
        end
        if r2 and Multilingual then
            for k, v in pairs( r2 ) do
                if v  and  not Multilingual.isLang( k, true ) then
                    Fault( string.format( "%s <code>lang=%s</code>",
                                          "Invalid",
                                          k ) )
                end
            end -- for k, v
        end
    end
    return r1, r2
end -- faraway()



local function fashioned( about, asked, assign )
    -- Create description head
    -- Parameter:
    --     about   -- table, supposed to contain description
    --     asked   -- true, if mandatory description
    --     assign  -- <block>, if to be equipped
    -- Returns <block>, with head, or nil
    local para = assign or 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" )
            plus:css( "text-align", "left" )
            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( fair( v ) ) )
            end -- for k, v
            if Config.loudly then
                plus = mw.html.create( "div" )
                              :css( "background-color",
                                    "#" .. Config.debugmultilang )
                              :node( plus )
            else
                plus:addClass( "templatedata-maintain" )
                    :css( "display", "none" )
            end
        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 -- fashioned()



local function fatten( access )
    -- Create table row for sub-headline
    -- Parameter:
    --     access  -- string, with name
    -- Returns <tr>
    local param     = Data.tree.params[ access ]
    local sub, sort = access:match( "(=+)%s*(%S.*)$" )
    local headline  = mw.html.create( string.format( "h%d", #sub ) )
    local r         = mw.html.create( "tr" )
    local td        = mw.html.create( "td" )
                             :attr( "colspan", "5" )
                             :attr( "data-sort-value",  "!" .. sort )
    local s
    if param.style then
        s = type( param.style )
        if s == "table" then
            td:css( param.style )
        elseif s == "string" then
            td:cssText( param.style )
        end
    end
    s = fashioned( param, false, headline )
    if s then
        headline = s
    else
        headline:wikitext( sort )
    end
    td:node( headline )
    r:node( td )
    return r
end -- fatten()



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
        if Data.heirs then
            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              = { }
                    if p[ v ] then
                        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
                    else
                        Fault( "No params[] inherits " .. v )
                    end
                end
            end -- for k, v
        end
    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 favorize()
    -- Local customization issues
    local boole  = { ["font-size"] = "125%" }
    local l, cx = pcall( mw.loadData,
                         TemplateData.frame:getTitle() .. "/config" )
    local scripting, style
    TemplateData.ltr = not mw.language.getContentLanguage():isRTL()
    if TemplateData.ltr then
        scripting = "left"
    else
        scripting = "right"
    end
    boole[ "margin-" .. scripting ] = "3em"
    Permit.boole = { [false] = { css  = boole,
                                 lead = true,
                                 show = "&#x2610;" },
                     [true]  = { css  = boole,
                                 lead = true,
                                 show = "&#x2611;" } }
    Permit.css   = { }
    for k, v in pairs( Permit.colors ) do
        if k == "tableheadbg" then
            k = "tablehead"
        end
        if k == "fg" then
            style = "color"
        else
            style = "background-color"
        end
        Permit.css[ k ] = { }
        Permit.css[ k ][ style ] = "#" .. v
    end -- for k, v
    if type( cx ) == "table" then
        local c, s
        if type( cx.permit ) == "table" then
            if type( cx.permit.boole ) == "table" then
                if type( cx.permit.boole[ true ] ) == "table" then
                    Permit.boole[ false ]  = cx.permit.boole[ false ]
                end
                if type( cx.permit.boole[ true ] ) == "table" then
                    Permit.boole[ true ]  = cx.permit.boole[ true ]
                end
            end
            if type( cx.permit.css ) == "table" then
                for k, v in pairs( cx.permit.css ) do
                    if type( v ) == "table" then
                        Permit.css[ k ] = v
                    end
                end -- for k, v
            end
        end
        for k, v in pairs( Config.basicCnf ) do
            s = type( cx[ k ] )
            if s == "string"  or  s == "table" then
                Config[ v ] = cx[ k ]
            end
        end -- for k, v
    end
    if type( Config.subpage ) ~= "string"  or
       type( Config.suffix ) ~= "string" then
        local got = mw.message.new( "templatedata-doc-subpage" )
        local suffix
        if got:isDisabled() then
            suffix = "doc"
        else
            suffix = got:plain()
        end
        if type( Config.subpage ) ~= "string" then
            Config.subpage = string.format( "/%s$", suffix )
        end
        if type( Config.suffix ) ~= "string" then
            Config.suffix = string.format( "%%s/%s", suffix )
        end
    end
end -- favorize()



local function feasible( all, at, about )
    -- Deal with suggestedvalues within parameter
    -- Parameter:
    --     all    -- parameter details
    --               .default
    --               .type
    --     at     -- string, with parameter name
    --     about  -- suggestedvalues  -- table,
    --                                   value and possibly description
    --                                   table may have elements:
    --                                    .code    -- mandatory
    --                                    .label   -- table|string
    --                                    .support -- table|string
    --                                    .icon    -- string
    --                                    .class   -- table|string
    --                                    .css     -- table
    --                                    .style   -- string
    --                                    .less    -- true: suppress code
    -- Returns
    --     1: mw.html object <ul>
    --     2: sequence table with values, or nil
    local h = { }
    local e, r1, r2, s, v
    if #about > 0 then
        for i = 1, #about do
            e = about[ i ]
            s = type( e )
            if s == "table" then
                if type( e.code ) == "string" then
                    s = mw.text.trim( e.code )
                    if s == "" then
                        e = nil
                    else
                        e.code = s
                    end
                else
                    e = nil
                    s = string.format( "params.%s.%s[%d] %s",
                                       at,
                                       "suggestedvalues",
                                       i,
                                       "MISSING 'code:'" )
                end
            elseif s == "string" then
                s = mw.text.trim( e )
                if s == "" then
                    e = nil
                    s = string.format( "params.%s.%s[%d] EMPTY",
                                       at, "suggestedvalues", i )
                    Fault( s )
                else
                    e = { code = s }
                end
            elseif s == "number" then
                e = { code = tostring( e ) }
            else
                s = string.format( "params.%s.%s[%d] INVALID",
                                   at, "suggestedvalues", i )
                Fault( s )
                e = false
            end
            if e then
                v = v  or  { }
                table.insert( v, e )
                if h[ e.code ] then
                    s = string.format( "params.%s.%s REPEATED %s",
                                       at,
                                       "suggestedvalues",
                                       e.code )
                    Fault( s )
                else
                    h[ e.code ] = true
                end
            end
        end -- for i
    else
        Fault( string.format( "params.%s.suggestedvalues %s",
                              at, "NOT AN ARRAY" ) )
    end
    if v then
        local code, d, k, less, story, swift, t, u
        r1 = mw.html.create( "ul" )
        r2 = { }
        for i = 1, #v do
            u = mw.html.create( "li" )
            e = v[ i ]
            table.insert( r2, e.code )
            story = false
            less  = ( e.less == true )
            if not less then
                swift = e.code
                if e.support then
                    local scream, support
                    s = type( e.support )
                    if s == "string" then
                        support = e.support
                    elseif s == "table" then
                        support = faraway( e.support )
                    else
                        scream = "INVALID"
                    end
                    if support then
                        s = mw.text.trim( support )
                        if s == "" then
                            scream = "EMPTY"
                        elseif s:find( "[%[%]|%<%>]" ) then
                            scream = "BAD PAGE"
                        else
                            support = s
                        end
                    end
                    if scream then
                        s = string.format( "params.%s.%s[%d].support %s",
                                           at,
                                           "suggestedvalues",
                                           i,
                                           scream )
                        Fault( s )
                    else
                        swift = string.format( "[[:%s|%s]]",
                                               support, swift )
                    end
                end
                if all.type:sub( 1, 5 ) == "wiki-"  and
                   swift == e.code then
                    local rooms = { file = 6,
                                    temp = 10,
                                    user = 2 }
                    local ns = rooms[ all.type:sub( 6, 9 ) ]  or  0
                    t = mw.title.makeTitle( ns, swift )
                    if t and t.exists then
                        swift = string.format( "[[:%s|%s]]",
                                               t.prefixedText, swift )
                    end
                end
                if e.code == all.default then
                    k = 800
                else
                    k = 300
                end
                code = mw.html.create( "code" )
                              :css( "font-weight", tostring( k ) )
                              :css( "white-space", "nowrap" )
                              :wikitext( swift )
                u:node( code )
            end
            if e.class then
                s = type( e.class )
                if s == "string" then
                    u:addClass( e.class )
                elseif s == "table" then
                    for k, s in pairs( e.class ) do
                        u:addClass( s )
                    end -- for k, s
                else
                    s = string.format( "params.%s.%s[%d].class INVALID",
                                       at, "suggestedvalues", i )
                    Fault( s )
                end
            end
            if e.css then
                if type( e.css ) == "table" then
                    u:css( e.css )
                else
                    s = string.format( "params.%s.%s[%d].css INVALID",
                                       at, "suggestedvalues", i )
                    Fault( s )
                end
            end
            if e.style then
                if type( e.style ) == "string" then
                    u:cssText( e.style )
                else
                    s = string.format( "params.%s.%s[%d].style INVALID",
                                       at, "suggestedvalues", i )
                    Fault( s )
                end
            end
            if all.type == "wiki-file-name"  and  not e.icon then
                e.icon = e.code
            end
            if e.label then
                s = type( e.label )
                if s == "string" then
                    s = mw.text.trim( e.label )
                    if s == "" then
                        s = string.format( "params.%s.%s[%d].label %s",
                                           at,
                                           "suggestedvalues",
                                           i,
                                           "EMPTY" )
                        Fault( s )
                    else
                        story = s
                    end
                elseif s == "table" then
                    story = faraway( e.label )
                else
                    s = string.format( "params.%s.%s[%d].label INVALID",
                                       at, "suggestedvalues", i )
                    Fault( s )
                end
            end
            s = false
            if type( e.icon ) == "string" then
                t = mw.title.makeTitle( 6, e.icon )
                if t and t.file.exists then
                    local g = mw.html.create( "span" )
                    s = string.format( "[[%s|16px]]", t.prefixedText )
                    g:attr( "role", "presentation" )
                     :wikitext( s )
                    s = tostring( g )
                end
            end
            if not s  and  not less  and  e.label then
                s = mw.ustring.char( 0x2013 )
            end
            if s then
                d = mw.html.create( "span" )
                           :wikitext( s )
                if TemplateData.ltr then
                    if not less then
                        d:css( "margin-left", "0.5em" )
                    end
                    if story then
                        d:css( "margin-right", "0.5em" )
                    end
                else
                    if not less then
                        d:css( "margin-right", "0.5em" )
                    end
                    if story then
                        d:css( "margin-left", "0.5em" )
                    end
                end
                u:node( d )
            end
            if story then
                u:wikitext( story )
            end
            r1:newline()
              :node( u )
        end -- for i
    end
    if not r1  and  v ~= false then
        Fault( string.format( "params.%s.suggestedvalues INVALID", at ) )
        r1 = mw.html.create( "code" )
                    :addClass( "error" )
                    :wikitext( "INVALID" )
    end
    return r1, r2
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   = { }
            local given    = { }
            for k, v in pairs( Data.tree.params ) do
                i = facet( k, 1 )
                if type( v ) == "table" then
                    if type( v.label ) == "string" then
                        s = mw.text.trim( v.label )
                        if s == "" then
                            s = k
                        end
                    else
                        s = k
                    end
                    if given[ s ] then
                        if given[ s ] == 1 then
                            local scream = "Parameter label '%s' detected multiple times"
                            Fault( string.format( scream, s ) )
                            given[ s ] = 2
                        end
                    else
                        given[ s ] = 1
                    end
                end
                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 eager   = 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 styles  = "mw-templatedata-doc-param-"
    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" )
                  :addClass( styles .. "name" )
                  :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, syn
        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" ) )
                        :wikitext( s )
                else
                    syn = mw.html.create( "span" )
                                 :addClass( styles .. "alias" )
                                 :css( "white-space", "nowrap" )
                                 :wikitext( s )
                    code:node( syn )
                end
            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(  factory( "invalid-value" ):gsub( "$1", s )  )
            legal = false
        end
    end

    -- description etc.
    s = fashioned( param )
    if s then
        desc:node( s )
    end
    if param.style then
        s = type( param.style )
        if s == "table" then
            desc:css( param.style )
        elseif s == "string" then
            desc:cssText( param.style )
        end
    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
        for i = 1, #details do
            s    = details[ i ]
            show = param[ s ]
            if show then
                dd      = mw.html.create( "dd" )
                section = factory( "doc-param-" .. s )
                if param.type == "boolean"   and
                   ( show == "0" or show == "1" ) then
                    local boole = Permit.boole[ ( show == "1" ) ]
                    if boole.lead == true then
                        dd:node( mw.html.create( "code" )
                                        :wikitext( show ) )
                          :wikitext( " " )
                    end
                    if type( boole.show ) == "string" then
                        local v = mw.html.create( "span" )
                                         :attr( "aria-hidden", "true" )
                                         :wikitext( boole.show )
                        if boole.css then
                            v:css( boole.css )
                        end
                        dd:node( v )
                    end
                    if type( boole.suffix ) == "string" then
                        dd:wikitext( boole.suffix )
                    end
                    if boole.lead == false then
                        dd:wikitext( " " )
                          :node( mw.html.create( "code" )
                                        :wikitext( show ) )
                    end
                elseif s == "suggestedvalues" then
                    local v, css, class, ts = facilities( param )
                    if v then
                        local ul
                        ul, v = feasible( param, access, v )
                        if v then
                            dd:newline()
                              :node( ul )
                            if css then
                                dd:css( css )
                                if class then
                                    dd:addClass( class )
                                end
                                if ts then
                                    dd:newline()
                                    dd:node( ts )
                                end
                            end
                            Data.params[ access ].suggestedvalues = v
                        end
                    end
                else
                    dd:wikitext( show )
                end
                dl:node( mw.html.create( "dt" )
                                :wikitext( section ) )
                  :node( dd )
            end
        end -- i = 1, #details
        desc:node( dl )
    end

    -- type
    if type( param.type ) == "string" then
        param.type = mw.text.trim( param.type )
        if param.type == "" then
            param.type = false
        end
    end
    if param.type then
        s     = Permit.types[ param.type ]
        typed = mw.html.create( "td" )
                  :addClass( styles .. "type" )
        if s then
            if s == "string" then
                Data.params[ access ].type = s
                typed:wikitext( factory( "doc-param-type-" .. s ) )
                     :tag( "br" )
                typed:node( mw.html.create( "span" )
                                   :addClass( "error" )
                                   :wikitext( param.type ) )
                Data.lasting = true
            else
                local support = Config[ "support4" .. param.type ]
                s = factory( "doc-param-type-" .. param.type )
                if support then
                    s = string.format( "[[%s|%s]]", support, s )
                end
                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(  factory( "invalid-value" ):gsub( "$1", s )  )
            legal = false
        end
    else
        typed = mw.html.create( "td" )
                   :wikitext( factory( "doc-param-type-unknown" ) )
        Data.params[ access ].type = "unknown"
        if param.default then
            Data.params[ access ].default = nil
            Fault( "Default value requires <code>type</code>" )
            legal = false
        end
    end
    typed:addClass( "navigation-not-searchable" )
    -- status
    if param.required then
        mode = 1
        if param.autovalue then
            Fault( string.format( "autovalued <code>%s</code> required",
                                  access ) )
            legal = false
        end
        if param.default then
            Fault( string.format( "Defaulted <code>%s</code> required",
                                  access ) )
            legal = false
        end
        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 = factory( "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
        if param.suggested  and  mode == 4 then
            s = string.format( "Suggesting deprecated <code>%s</code>",
                               access )
            Fault( s )
            legal = false
        end
    end
    eager:attr( "data-sort-value", tostring( mode ) )
                :node( ranking )
                :addClass( string.format( "%sstatus-%s %s",
                                          styles, status,
                                          "navigation-not-searchable" ) )

    -- <tr>
    r:attr( "id",  "templatedata:" .. mw.uri.anchorEncode( access ) )
     :css( Permit.css[ status ] )
     :addClass( styles .. status )
     :node( begin )
     :node( code )
     :node( desc )
     :node( typed )
     :node( eager )
     :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 tbl = mw.html.create( "table" )
        local tr  = mw.html.create( "tr" )
        feat()
        if Data.order  and  #Data.order > 1 then
            tbl:addClass( "sortable" )
        end
        if type( Config.classTable ) == "table" then
            for k, v in pairs( Config.classTable ) do
                tbl:addClass( v )
            end -- for k, v
        end
        if type( Config.cssTable ) == "table" then
            tbl:css( Config.cssTable )
        end
        tr:addClass( "navigation-not-searchable" )
          :node( mw.html.create( "th" )
                        :attr( "colspan", "2" )
                        :css( Permit.css.tablehead )
                        :wikitext( factory( "doc-param-name" ) ) )
          :node( mw.html.create( "th" )
                        :css( Permit.css.tablehead )
                        :wikitext( factory( "doc-param-desc" ) ) )
          :node( mw.html.create( "th" )
                        :css( Permit.css.tablehead )
                        :wikitext( factory( "doc-param-type" ) ) )
          :node( mw.html.create( "th" )
                        :css( Permit.css.tablehead )
                        :wikitext( factory( "doc-param-status" ) ) )
        tbl:newline()
--         :node( mw.html.create( "thead" )
                         :node( tr )
--              )
           :newline()
        if Data.order then
            local leave, s
            for i = 1, #Data.order do
                s = Data.order[ i ]
                if s:sub( 1, 1 ) == "=" then
                    leave = true
                    tbl:node( fatten( s ) )
                    Data.order[ i ] = false
                elseif s:match( "[=|]" ) then
                    Fault( string.format( "Bad param <code>%s</code>",
                                          s ) )
                else
                    tbl:node( feature( s ) )
                end
            end -- for i = 1, #Data.order
            if leave then
                for i = #Data.order, 1, -1 do
                    if not Data.order[ i ] then
                        table.remove( Data.order, i )
                    end
                end -- for i = #Data.order, 1, -1
            end
            Data.tag.paramOrder = Data.order
        end
        if Config.cssTabWrap or Data.scroll then
            r = mw.html.create( "div" )
            if type( Config.cssTabWrap ) == "table" then
                r:css( Config.cssTabWrap )
            elseif type( Config.cssTabWrap ) == "string" then
                -- deprecated
                r:cssText( Config.cssTabWrap )
            end
            if Data.scroll then
                r:css( "height",   Data.scroll )
                 :css( "overflow", "auto" )
            end
            r:node( tbl )
        else
            r = tbl
        end
    end
    return r
end -- features()



local function fellow( any, assigned, at )
    -- Check sets[] parameter and issue error message, if necessary
    -- Parameter:
    --     any       -- should be number
    --     assigned  -- parameter name
    --     at        -- number, of set
    local s
    if type( any ) ~= "number" then
        s = "<code>sets[%d].params[%s]</code>??"
        Fault( string.format( s,
                              at,
                              mw.text.nowiki( tostring( any ) ) ) )
    elseif type( assigned ) == "string" then
        if not Data.got.params[ assigned ] then
            s = "<code>sets[%d].params %s</code> is undefined"
            Fault( string.format( s, at, assigned ) )
        end
    else
        s = "<code>sets[%d].params[%d] = %s</code>??"
        Fault( string.format( s,  k,  type( assigned ) ) )
    end
end -- fellow()



local function fellows()
    -- Check sets[] and issue error message, if necessary
    local s
    if type( Data.got.sets ) == "table" then
        if type( Data.got.params ) == "table" then
            for k, v in pairs( Data.got.sets ) do
                if type( k ) == "number" then
                    if type( v ) == "table" then
                        for ek, ev in pairs( v ) do
                            if ek == "label" then
                                s = type( ev )
                                if s ~= "string"  and
                                   s ~= "table" then
                                    s = "<code>sets[%d].label</code>??"
                                    Fault( string.format( s, k ) )
                                end
                            elseif ek == "params"  and
                                type( ev ) == "table" then
                                for pk, pv in pairs( ev ) do
                                    fellow( pk, pv, k )
                                end -- for pk, pv
                            else
                                ek = mw.text.nowiki( tostring( ek ) )
                                s  = "<code>sets[%d][%s]</code>??"
                                Fault( string.format( s, k, ek ) )
                            end
                        end -- for ek, ev
                    else
                        k = mw.text.nowiki( tostring( k ) )
                        v = mw.text.nowiki( tostring( v ) )
                        s = string.format( "<code>sets[%s][%s]</code>??",
                                           k, v )
                        Fault( s )
                    end
                else
                    k = mw.text.nowiki( tostring( k ) )
                    s = string.format( "<code>sets[%s]</code> ?????", k )
                    Fault( s )
                end
            end -- for k, v
        else
            s = "<code>params</code> required for <code>sets</code>"
            Fault( s )
        end
    else
        s = "<code>sets</code> needs to be of <code>object</code> type"
        Fault( s )
    end
end -- fellows()



local function finalize( advance )
    -- Wrap presentation into frame
    -- Parameter:
    --     advance  -- true, for nice
    -- Returns string
    local r, lapsus
    if Data.div then
        r = tostring( Data.div )
    elseif Data.strip then
        r = Data.strip
    else
        lapsus = true
        r      = ""
    end
    r = r .. failures()
    if Data.source then
        local live = ( advance or lapsus )
        if not live then
            live = TemplateData.frame:preprocess( "{{REVISIONID}}" )
            live = ( live == "" )
        end
        if live then
            r = r .. fancy( advance, lapsus )
        end
    end
    return r
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 for VE
    -- 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
        if r:find( "<exportonly>", 1, true ) then
            r = r:gsub( "</?exportonly>", "" )
        end
        if r:find( "''", 1, true ) then
            r = r:gsub( "'''", "" ):gsub( "''", "" )
        end
        if r:find( "<", 1, true ) then
            local Text = Fetch( "Text" )
            r = Text.getPlain( r:gsub( "<br */?>", "\r\n" ) )
        end
        if r:find( "[", 1, true ) then
            local WLink = Fetch( "WLink" )
            if WLink.isBracketedURL( r ) then
                r = r:gsub( "%[([hf]tt?ps?://%S+) [^%]]+%]", "%1" )
            end
            r = WLink.getPlain( r )
        end
        if r:find( "&", 1, true ) then
            r = mw.text.decode( r )
            if r:find( "&shy;", 1, true ) then
                r = r:gsub( "&shy;", "" )
            end
        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"  and  k ~= "format" 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 = fair( v )
                        elseif s == "table" then
                            local translated
                            v, translated = faraway( v )
                            if v then
                                if translated  and
                                   k == "description" then
                                    elem = { [ 1 ] = fair( v ),
                                             [ 2 ] = translated }
                                else
                                    elem = fair( v )
                                end
                            else
                                elem = false
                            end
                        end
                        if type( v ) == "string" then
                            if k == "deprecated" then
                                if v == "1" then
                                    v = true
                                elseif v == "0" then
                                    v = false
                                end
                                elem = v
                            elseif scope:find( "nowiki", 1, true ) then
                                elem = mw.text.nowiki( v )
                                elem = elem:gsub( "&#13;\n", "<br>" )
                                v    = v:gsub( string.char( 13 ),  "" )
                            else
                                v = flat( v )
                            end
                        elseif s == "boolean" then
                            if scope:find( "boolean", 1, true ) then
                                elem = v
                            else
                                s = "Type <code>boolean</code> bad for "
                                    .. f( k, slot )
                                Fault( s )
                            end
                        end
                    else
                        if k == "params"  and  not access then
                            v    = nil
                            elem = nil
                        elseif k == "format"  and  not access then
                            elem = mw.text.decode( v )
                            v    = nil
                        elseif k == "inherits" then
                            elem = v
                            if not Data.heirs then
                                Data.heirs = { }
                            end
                            Data.heirs[ slot ] = v
                            v                  = nil
                        elseif k == "style" then
                            elem = 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 type( v ) == "string"  and
                                   v.sub( 1, 1 ) == "=" then
                                    v = nil
                                else
                                    if not Data.params then
                                        Data.params = { }
                                    end
                                    Data.params[ slot ] = { }
                                    tag = Data.params[ slot ]
                                end
                            else
                                Data.tag = { }
                                tag      = Data.tag
                            end
                        end
                        if type( v ) ~= "nil"  and
                           k ~= "suggestedvalues" then
                            tag[ k ] = v
                        end
                    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
        if not access  and Data.got.sets then
            fellows()
        end
    else
        Fault( f() .. " needs to be of <code>object</code> type" )
    end
end -- focus()



local function format()
    -- Build formatted element
    -- Returns <inline>
    local source = Data.tree.format:lower()
    local r, s
    if source == "inline"  or  source == "block" then
        r = mw.html.create( "i" )
                   :wikitext( source )
    else
        local code
        if source:find( "|", 1, true ) then
            local scan = "^[\n ]*%{%{[\n _]*|[\n _]*=[\n _]*%}%}[\n ]*$"
            if source:match( scan ) then
                code = source:gsub( "\n", "N" )
            else
                s = mw.text.nowiki( source ):gsub( "\n", "&#92;n" )
                s = tostring( mw.html.create( "code" )
                                     :wikitext( s ) )
                Fault( "Invalid format " .. s )
                source = false
            end
        else
            local words = mw.text.split( source, "%s+" )
            local show, start, support, unknown
            for i = 1, #words do
                s = words[ i ]
                if i == 1 then
                    start = s
                end
                support = Permit.builder[ s ]
                if support == start  or
                   support == "*" then
                    Permit.builder[ s ] = true
                elseif s:match( "^[1-9]%d?" ) and
                       Permit.builder.align then
                    Permit.builder.align = tonumber( s )
                else
                    if unknown then
                        unknown = string.format( "%s %s", unknown, s )
                    else
                        unknown = s
                    end
                end
            end -- i = 1, #words
            if unknown then
                s = tostring( mw.html.create( "code" )
                                     :css( "white-space", "nowrap" )
                                     :wikitext( s ) )
                Fault( "Unknown/misplaced format keyword " .. s )
                source = false
                start  = false
            end
            if start == "inline" then
                if Permit.builder.half == true then
                    show = "inline half"
                    code = "{{_ |_=_}}"
                elseif Permit.builder.grouped == true then
                    show = "inline grouped"
                    code = "{{_ | _=_}}"
                elseif Permit.builder.spaced == true then
                    show = "inline spaced"
                    code = "{{_ | _ = _ }}"
                end
                if Permit.builder.newlines == true then
                    show = show or "inline"
                    code = code or "{{_|_=_}}"
                    show = show .. " newlines"
                    code = string.format( "N%sN", code )
                end
            elseif start == "block" then
                local space  = ""     -- amid "|" and name
                local spaced = " "    -- preceding "="
                local spacer = " "    -- following "="
                local suffix = "N"    -- closing "}}" on new line
                show = "block"
                if Permit.builder.indent == true then
                    start = " "
                    show = "block indent"
                else
                    start = ""
                end
                if Permit.builder.compressed == true then
                    spaced = ""
                    spacer = ""
                    show   = show .. " compressed"
                    if Permit.builder.last == true then
                        show = show .. " last"
                    else
                        suffix = ""
                    end
                else
                    if Permit.builder.lead == true then
                        show  = show .. " lead"
                        space = " "
                    end
                    if type( Permit.builder.align ) ~= "string" then
                        local n
                        s = " align"
                        if Permit.builder.align == true then
                            n = 0
                            if type( Data.got ) == "table"  and
                               type( Data.got.params ) == "table" then
                                for k, v in pairs( Data.got.params ) do
                                    if type( v ) == "table"  and
                                       not v.deprecated  and
                                       type( k ) == "string" then
                                        k = mw.ustring.len( k )
                                        if k > n then
                                            n = k
                                        end
                                    end
                                end -- for k, v
                            end
                        else
                            n = Permit.builder.align
                            if type( n ) == "number"  and  n > 1 then
                                s = string.format( "%s %d", s, n )
                            else
                                n = 0    -- How comes?
                            end
                        end
                        if n > 1 then
                            spaced = string.rep( "_",  n - 1 )  ..  " "
                        end
                        show = show .. s
                    elseif Permit.builder.after == true then
                        spaced = ""
                        show   = show .. " after"
                    elseif Permit.builder.dense == true then
                        spaced = ""
                        spacer = ""
                        show   = show .. " dense"
                    end
                    if Permit.builder.last == true then
                        suffix = spacer
                        show   = show .. " last"
                    end
                end
                code = string.format( "N{{_N%s|%s_%s=%s_%s}}N",
                                      start,
                                      space,
                                      spaced,
                                      spacer,
                                      suffix )
                if show == "block" then
                    show = "block newlines"
                end
            end
            if show then
                r = mw.html.create( "span" )
                           :wikitext( show )
            end
        end
        if code then
            source = code:gsub( "N", "\n" )
            code   = mw.text.nowiki( code ):gsub( "N", "&#92;n" )
            code   = mw.html.create( "code" )
                            :css( "margin-left",  "1em" )
                            :css( "margin-right", "1em" )
                            :wikitext( code )
            if r then
                r = mw.html.create( "span" )
                           :node( r )
                           :node( code )
            else
                r = code
            end
        end
    end
    if source and Data.tag then
        Data.tag.format = source
    end
    return r
end -- format()



local function formatter()
    -- Build presented documentation
    -- Returns <div>
    local r = mw.html.create( "div" )
    local x = fashioned( Data.tree, true, r )
    local s
    if x then
        r = x
    end
    if Data.leading then
        local toc = mw.html.create( "div" )
        local shift
        if Config.suppressTOCnum then
            toc:addClass( Config.suppressTOCnum )
            if type( Config.stylesTOCnum ) == "string" then
                local src = Config.stylesTOCnum .. "/styles.css"
                s = TemplateData.frame:extensionTag( "templatestyles",
                                                     nil,
                                                     { src = src } )
                r:newline()
                 :node( s )
            end
        end
        toc:addClass( "navigation-not-searchable" )
           :css( "margin-top", "0.5em" )
           :wikitext( "__TOC__" )
        if Data.sibling then
            local block = mw.html.create( "div" )
            if TemplateData.ltr then
                shift = "right"
            else
                shift = "left"
            end
            block:css( "float", shift )
                 :wikitext( Data.sibling )
            r:newline()
             :node( block )
             :newline()
        end
        r:newline()
         :node( toc )
         :newline()
        if shift then
            r:node( mw.html.create( "div" )
                           :css( "clear", shift ) )
             :newline()
        end
    end
    s = features()
    if s then
        if Data.leading then
            r:node( mw.html.create( "h" .. Config.nested )
                           :wikitext( factory( "doc-params" ) ) )
             :newline()
        end
        r:node( s )
    end
    if Data.shared then
        local global = mw.html.create( "div" )
                              :attr( "id", "templatedata-global" )
        local shift
        if TemplateData.ltr then
            shift = "right"
        else
            shift = "left"
        end
        global:css( "float", shift )
              :wikitext( string.format( "[[%s|%s]]",
                                        Data.shared, "Global" ) )
        r:newline()
         :node( global )
    end
    if Data.tree and Data.tree.format then
        local e = format()
        if e then
            local show = "Format"
            if Config.supportFormat then
                show = string.format( "[[%s|%s]]",
                                      Config.supportFormat, show )
            end
            r:node( mw.html.create( "p" )
                           :addClass( "navigation-not-searchable" )
                           :wikitext( show .. ": " )
                           :node( e ) )
        end
    end
    return r
end -- formatter()



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



local function full()
    -- Build survey table from JSON data, append invisible <templatedata>
    Data.div = mw.html.create( "div" )
                      :addClass( "mw-templatedata-doc-wrap" )
    if Permit.css.bg then
        Data.div:css( Permit.css.bg )
    end
    if Permit.css.fg then
        Data.div:css( Permit.css.fg )
    end
    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( formatter() )
    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
                Data.div:node( mw.html.create( "hr" )
                                      :css( { height = "7ex" } ) )
            else
                div:css( "display", "none" )
            end
            Data.div:node( div )
        end
    end
    if Data.lasting then
        Fault( "deprecated type syntax" )
    end
    if Data.less then
        Fault( Config.solo )
    end
end -- full()



local function furnish( adapt, arglist )
    -- Analyze transclusion
    -- Parameter:
    --     adapt    -- table, #invoke parameters
    --     arglist  -- table, template parameters
    -- Returns string
    local source
    favorize()
    -- deprecated:
    for k, v in pairs( Config.basicCnf ) do
        if adapt[ k ]  and  adapt[ k ] ~= "" then
            Config[ v ] = adapt[ k ]
        end
    end -- for k, v
    if arglist.heading  and  arglist.heading:match( "^[3-6]$" ) then
        Config.nested = arglist.heading
    else
        Config.nested = "2"
    end
    Config.loudly = faculty( arglist.debug or adapt.debug )
    Data.lazy     = faculty( arglist.lazy )  and  not Config.loudly
    Data.leading  = faculty( arglist.TOC )
    if Data.leading and arglist.TOCsibling then
        Data.sibling = mw.text.trim( arglist.TOCsibling )
    end
    if arglist.lang then
        Data.slang = arglist.lang:lower()
    elseif adapt.lang then
        Data.slang = adapt.lang:lower()
    end
    if arglist.JSON then
        source = arglist.JSON
    elseif arglist.Global then
        source = TemplateData.getGlobalJSON( arglist.Global,
                                             arglist.Local )
    elseif arglist[ 1 ] then
        local s     = mw.text.trim( arglist[ 1 ] )
        local start = s:sub( 1, 1 )
        if start == "<" then
            Data.strip = s
        elseif start == "{" then
            source = s
        elseif mw.ustring.sub( s, 1, 8 ) ==
               mw.ustring.char( 127, 39, 34, 96, 85, 78, 73, 81 ) then
            Data.strip = s
        end
    end
    if type( arglist.vertical ) == "string"  and
       arglist.vertical:match( "^%d*%.?%d+[emprx]+$" ) then
        Data.scroll = arglist.vertical
    end
    if not source then
        Data.title = mw.title.getCurrentTitle()
        source = find()
        if not source  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
    end
    if not Data.lazy then
        if not Data.title then
            Data.title = mw.title.getCurrentTitle()
        end
        Data.lazy = Data.title.text:match( Config.subpage )
    end
    if type( source ) == "string" then
        TemplateData.getPlainJSON( source )
    end
    return finalize( faculty( arglist.source ) )
end -- furnish()



Failsafe.failsafe = function ( atleast )
    -- Retrieve versioning and check for compliance
    -- Precondition:
    --     atleast  -- string, with required version
    --                         or wikidata|item|~|@ or false
    -- Postcondition:
    --     Returns  string  -- with queried version/item, also if problem
    --              false   -- if appropriate
    -- 2020-08-17
    local since  = atleast
    local last   = ( since == "~" )
    local linked = ( since == "@" )
    local link   = ( since == "item" )
    local r
    if last  or  link  or  linked  or  since == "wikidata" then
        local item = Failsafe.item
        since = false
        if type( item ) == "number"  and  item > 0 then
            local suited = string.format( "Q%d", item )
            if link then
                r = suited
            else
                local entity = mw.wikibase.getEntity( suited )
                if type( entity ) == "table" then
                    local seek = Failsafe.serialProperty or "P348"
                    local vsn  = entity:formatPropertyValues( seek )
                    if type( vsn ) == "table"  and
                       type( vsn.value ) == "string"  and
                       vsn.value ~= "" then
                        if last  and  vsn.value == Failsafe.serial then
                            r = false
                        elseif linked then
                            if mw.title.getCurrentTitle().prefixedText
                               ==  mw.wikibase.getSitelink( suited ) then
                                r = false
                            else
                                r = suited
                            end
                        else
                            r = vsn.value
                        end
                    end
                end
            end
        end
    end
    if type( r ) == "nil" then
        if not since  or  since <= Failsafe.serial then
            r = Failsafe.serial
        else
            r = false
        end
    end
    return r
end -- Failsafe.failsafe()



TemplateData.getGlobalJSON = function ( access, adapt )
    -- Retrieve TemplateData from a global repository (JSON)
    -- Parameter:
    --     access  -- string, with page specifier (on WikiMedia Commons)
    --     adapt   -- JSON string or table with local overrides
    -- Returns true, if succeeded
    local plugin = Fetch( "/global" )
    local r
    if type( plugin ) == "table"  and
       type( plugin.fetch ) == "function" then
        local s, got = plugin.fetch( access, adapt )
        if got then
            Data.got    = got
            Data.order  = got.paramOrder
            Data.shared = s
            r           = true
            full()
        else
            Fault( s )
        end
    end
    return r
end -- TemplateData.getGlobalJSON()



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()
        local lucky
        lucky, Data.got = pcall( mw.text.jsonDecode, Data.source )
        if type( Data.got ) == "table" then
            full()
        elseif not Data.strip then
            local scream = type( Data.got )
            if scream == "string" then
                scream = Data.got
            else
                scream = "Data.got: " .. scream
            end
            Fault( "fatal JSON error: " .. scream )
        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 )
    -- Template call
    local lucky, r
    TemplateData.frame = frame
    lucky, r = pcall( furnish, frame.args, frame:getParent().args )
    if not lucky then
        Fault( "INTERNAL: " .. r )
        r = failures()
    end
    return r
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 Failsafe.failsafe( since )  or  ""
end -- p.failsafe

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

return p