Wikipedia:Lua/Modul/TemplateData/en

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

Core functionality is improved presentation on documentation pages.

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.

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:

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 phab:T126150. 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.
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.
- phab:T125333 / phab:T137443 / phab:T160254 / phab:T52512
- 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 phab:T125333 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.

Functions for templates

Details

f

Improve TemplateData-presentation; used in Template: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

Version management

The Failsafe interface is heading for version management of globally distributed Lua modules. It enables modules equipped with this interface to

ensure, that a library module required by a template or another module available as local copy does support certain functionality, or complain if not.
administrate global updating and linking of module codes via Wikidata.

The Failsafe interface is present both at template level and for direct Lua access.

The functions in detail are (not all supported yet completely by every library):

Parameter
Value	Result	current
nothing `false`	local version ID	»2026-05-06«
Minimal version	version ID required at least date in ISO format It will be compared whether the current local implementation matches this version or later. empty, if minimal version not achieved	2001-01-01 → »2026-05-06« 2099-01-01 → »«
`wikidata`	version ID of global upstream version ID at Wikidata local, if not found there	»2026-05-06«
`item`	ID of the Wikidata item empty if not defined	`Q46997995`
`~`	Corresponding version ID locally and registered at Wikidata empty, if up to date version ID at Wikidata, if not equal	»«
`@`	Is the current (module) page linked correctly with Wikidata item? empty, if linked to the item which is supposed Iitem ID, if not
The return value is in template programming empty or under Lua `false`, otherwis a non-empty string as described.

Functions for Lua modules (API)

Some functions described above can be used by other modules:

local lucky, TemplateData = pcall( require, "Modul: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)

atleast
optional
nil or minimal version request or "wikidata"

Returns: string or false

TemplateData.getPlainJSON(adapt)

Reduce enhanced JSON information to MediaWiki JSON

adapt
string, with JSON (enhanced)

Returns: string, with JSON (MediaWiki )

TemplateData.test(adapt, arglist)

Simulation of template functionality

adapt
table, #invoke parameters
arglist
table, template parameters

Returns: string

Usage

Currently focussing on one template only:

Template:TemplateData

Dependencies

Configuration

A local module Module: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

helpDefault

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