Module:category tree

The following documentation is located at Module:category tree/documentation.

Useful links: subpage list • links • transclusions • testcases • sandbox

	Use WT:CLTR to propose category additions or changes.
	The category tree modules are intentionally protected. New topic or grammatical categories, or substantive changes to existing categories, need to obtain prior consensus. To do this, post at WT:CLTR (Wiktionary:Category and label treatment requests).

This is the documentation page for the generic category tree system, as well as for its submodules. Collectively, these modules handle generating the descriptions and categorization for all category pages which are automated as part of the category tree system (i.e. all categories except those that use manual wikicoding). All pages handled by the category tree should use {{auto cat}} as the text of the category page. (In some cases, parameters need to be specified to {{auto cat}}; see its documentation for details.)

For historical reasons, the generic category tree implementation is split between Module:category tree and Module:category tree/poscatboiler, but these two modules will eventually be merged. (Originally, Module:category tree was a generic module in the object-oriented tradition with many implementations, of which Module:category tree/poscatboiler was only one. It originally handled part-of-speech categories like Category:French nouns and Category:German lemmas, and corresponding "umbrella" categories such as Category:Nouns by language and Category:Lemmas by language; hence the name.)

The main data module at Module:category tree/data does not contain data itself, but rather imports the data from the category tree submodules, and applies some post-processing.

• To find which submodule implements a specific category, use the search box on the right.
• To add a new submodule, copy an existing submodule and modify its contents. Then, add its name to the subpages list at the top of Module:category tree/data.

The category tree system internally distinguishes the following types of categories:

1. Language categories. These are of the form LANG LABEL (e.g. Category:French lemmas and Category:English learned borrowings from Late Latin). Here, LANG is the name of a language, and LABEL can be anything, but should generally describe a topic that can apply to multiple languages. Note that the language mentioned by LANG must currently be a regular language, not an etymology-only language. (Etymology-only languages include lects such as Provençal, considered a variety of Occitan, and Biblical Hebrew, considered a variety of Hebrew. See here for the list of such lects.) Most language categories have an associated umbrella category; see below.
2. Umbrella categories. These are normally of the form LABEL by language, and group all categories with the same label. Examples are Category:Lemmas by language and Category:Learned borrowings from Late Latin by language. Note that the label appears with an initial lowercase letter in a language category, but with an initial uppercase letter in an umbrella category, consistent with the general principle that category names are capitalized. Umbrella categories themselves are grouped into umbrella metacategories, which group related umbrella categories under a given high-level topic. Examples are Category:Lemmas subcategories by language (which groups umbrella categories describing different types of lemmas, such as Category:Nouns by language and Category:Interrogative adverbs by language) and Category:Terms derived from Proto-Indo-European roots (which groups umbrella categories describing terms derived from particular Proto-Indo-European roots, such as Category:Terms derived from the Proto-Indo-European root *preḱ- and Category:Terms derived from the Proto-Indo-European root *bʰeh₂- (speak)). The names of umbrella metacategories are not standardized (although many end in subcategories by language), and internally they are handled as raw categories; see below.
   • Note that umbrella categories are just a special type of parent category with built-in support in the category-handling system. In particular, some types of categories have what is logically an umbrella category but which has a nonstandard name. These are handled as just another parent category, with a separate raw-category entry for the parent itself. An example is categories of the form LANG phrasebook/AREA (e.g. Category:English phrasebook/Health), whose umbrella category has the nonstandard name Phrasebooks by language/AREA (e.g. Category:Phrasebooks by language/Health). Another example is categories of the form LANG terms borrowed back into LANG, with a nonstandard umbrella category Category:Terms borrowed back into the same language. Both of these examples are handled by disabling the standard umbrella category support and listing the nonstandard umbrella category as an additional parent.
   • Some umbrella categories are missing the by language suffix; an example is Category:Terms borrowed from Latin, which groups categories of the form LANG terms borrowed from Latin. There is special support for umbrella categories of this nature, so they do not need to be handled as described above for umbrella categories with nonstandard names.
3. Language-specific categories. These are of the same form LANG LABEL as regular language categories, but with the difference that the label in question applies only to a single language, rather than to all or a large group of languages. Examples are Category:Belarusian class 4c verbs, Category:Dutch separable verbs with bloot, and Category:Japanese kanji by kan'yōon reading. For these categories, it does not make sense to have a corresponding umbrella category.
4. Raw categories. These can have any form whatsoever, and may or may not have a language name in them. Examples are Category:Requests for images in Korean entries and Category:Rhymes:Polish/ajkɛ (which logically are language categories but do not follow the standard format of a language category); Category:Phrasebooks by language/Health (which is logically an umbrella category, but again with a nonstandard name); Category:Terms by etymology subcategories by language (an umbrella metacategory); and Category:Templates (a miscellaneous high-level category).

Under the hood, the category tree system distinguishes two types of implementations for categories: individual labels (or individual raw categories), and handlers. Individual labels describe a single label, such as nouns or refractory rhymes. Similarly, an individual raw category describes a single raw category. Handlers, on the other hand, describe a whole class of similar labels or raw categories, e.g. labels of the form learned borrowings from SOURCE where SOURCE is any language or etymology language. Handlers are more powerful than individual labels, but require knowledge of Lua to implement.

A sample entry is as follows (in this case, found in Module:category tree/lemmas):

labels = {
	description = "{{{langname}}} terms that give attributes to nouns, extending their definitions.",
	parents = {"lemmas"},
	umbrella_parents = "Lemmas subcategories by language",
}

This generates the description and categorization for all categories of the form "LANG adjectives" (e.g. Category:English adjectives or Category:Norwegian Bokmål adjectives), as well as for the umbrella category Category:Adjectives by language.

The meanings of these fields are as follows:

• The description field gives the description text that will appear when a user visits the category page. Here, {{{langname}}} is automatically replaced with the name of the language in question. The text in this field is also used to generate the description of the umbrella category Category:Adjectives by language, by chopping off the {{{langname}}} and capitalizing the next letter.
• The parents field gives the labels of the parent categories. For example, Category:English adjectives will have Category:English lemmas as its parent category, and Category:Norwegian Bokmål adjectives will have Category:Norwegian Bokmål lemmas as its parent category. The umbrella category Category:Adjectives by language will automatically be added as an additional parent.
• The umbrella_parents field specifies the parent category of the umbrella category Category:Adjectives by language (i.e. the umbrella metacategory which this page belongs to; see #Concepts above).

The following fields are recognized for the object describing a label:

parents

A table listing one or more parent labels of this label. This controls the parent categories that the category is contained within, as well as the chain of breadcrumbs appearing across the top of the page (see below).

• An item in the table can be either a single string (the parent label), or a table containing (at least) the two elements name and sort. In the latter case, name specifies the parent label name, while the sort value specifies the sort key to use to sort it in that category. The default sort key is the category's label.
• The first listed parent controls the category's parent breadcrumb in the chain of breadcrumbs at the top of the page. (The breadcrumb of the category itself is determined by the breadcrumb setting, as described below.)
• Normally the specified parent label refers to another category of the same type. That is, if the category is a language category, the parent label specifies another language category with the same language, and if the category is a raw category, the parent label specifies another raw category. This can be changed as follows:
  • If the category is a language category:
    • Add the property raw = true to specify that the parent is a raw category.
    • Add the property lang = code to specify that the parent is a language category for the language code code instead of the current language. Note that template substitutions happen in the lang field; see #Template substitutions in field values below.
    • Add the property lang = false to specify that the parent is an umbrella category.
  • If the category is a raw category:
    • Add the properties is_label = true and lang = code to specify that the parent is a language category with the specified language code code. Template substitutions happen in the lang field, as above.
    • Add the properties is_label = true and lang = false to specify that the parent is an umbrella category.
• If a parent label begins with Category: it is interpreted as a category outside the category tree system. It can still have its own sort key as usual.
• Parent items can also have the properties sc = script_code to specify a script code script_code for script-specific categories (e.g. Category:Pali nouns in Thai script) and/or args = {...} to specify additional arguments, for categories implemented using a handler that accepts or requires additional arguments passed to {{auto cat}} (e.g. a category like Category:Latin terms suffixed with -inus or Category:Okinawan language). Template substitutions happen in the values of both of these properties; see #Template substitutions in field values below.

description

A plain English description for the label. This should generally be no longer than one sentence. Place additional, longer explanatory text in the additional field described below, and put {{wikipedia}} boxes in the topright field described below so that they are correctly right-aligned with the description. Template invocations and special template-like references such as {{{langname}}} and {{{langcode}}} will be expanded appropriately; see #Template substitutions in field values below.

breadcrumb

The text of the last breadcrumb that appears at the top of the category page.

• By default, it is the same as the category label, with the first letter capitalized.
• The value can be either a string, or a table containing two elements called name and nocap. In the latter case, name specifies the breadcrumb text, while nocap can be used to disable the automatic capitalization of the breadcrumb text that normally happens.
• Note that the breadcrumbs collectively are the chain of links that serve as a navigation aid for the hierarchical organization of categories. For example, a category like Category:French adjectives will have a breadcrumb chain similar to "Fundamental » All languages » French » Lemmas » Adjectives", where each breadcrumb is a link to a category at the appropriate level. The last breadcrumb here is "Adjectives", and its text is controlled by this field.

displaytitle

Apply special formatting such as italics to the category page title, as with the {{DISPLAYTITLE:...}} magic word (see mw:Help:Magic words). The value of this is either a string (which should be the formatted category title, without the preceding Category:) or a Lua function to generate the formatted category title. A Lua function is most useful inside of a handler (see #Handlers below). The Lua function is passed two parameters, the raw category title (without the preceding Category:) and the language object of the category's language (or nil for umbrella categories), and should return the formatted category title (again without the preceding Category:). If the value of this field is a string, template invocations and special template-like references such as {{{langname}}} and {{{langcode}}} will be expanded appropriately; see below. See Module:category tree/etymology and Module:category tree/lang/nl for examples of using displaytitle.

topright

Introductory text to display right-aligned, before the edit and recent-entries boxes on the right side. This field should be used for {{wikipedia}} and other similar boxes. Template invocations and special template-like references such as {{{langname}}} and {{{langcode}}} are expanded appropriately, just as with description; see #Template substitutions in field values below. Compare the preceding field, which is similar to topright but used for left-aligned text placed above the description.

preceding

Introductory text to display directly before the text in the description field. The difference between the two is that description text will also be shown in the list of children categories shown on the parent category's page, while the preceding text will not. For this reason, use preceding instead of description for {{also}} hatnotes and similar text, and keep description relatively short. Template invocations and special template-like references such as {{{langname}}} and {{{langcode}}} are expanded appropriately, just as with description; see #Template substitutions in field values below. Compare the topright field, which is similar to preceding but is right-aligned, placed above the edit and recent-entries boxes.

additional

Additional text to display directly after the text in the the description field. The difference between the two is that description text will also be shown in the list of children categories shown on the parent category's page, while the additional text will not. For this reason, use additional instead of description for long explanatory notes, See also references and the like, and keep description relatively short. Template invocations and special template-like references such as {{{langname}}} and {{{langcode}}} are expanded appropriately, just as with description; see #Template substitutions in field values below.

umbrella

A table describing the umbrella category that collects all language-specific categories associated with this label, or the special value false to indicate that there is no umbrella category. The umbrella category is normally called "LABEL by language". For example, for adjectives, the umbrella category is named Category:Adjectives by language, and is a parent category (in addition to any categories specified using parents) of Category:English adjectives, Category:French adjectives, Category:Norwegian Bokmål adjectives, and all other language-specific categories holding adjectives. This table contains the following fields:

name

The name of the umbrella category. It defaults to "LABEL by language". You should not use this, even if the umbrella category has a nonstandard name, because if you set it, you will have to modify Module:category tree to recognize the new name of the umbrella category. Instead, set umbrella = false and list the nonstandard umbrella category as an additional parent (and add a raw-category entry for the umbrella category itself; see the implementation of categories like Category:English terms borrowed back into English for an example).

description

A plain English description for the umbrella category. By default, it is derived from the description field of the category itself by removing any {{{langname}}}, {{{langcode}}} or {{{langcat}}} template parameter reference and capitalizing the remainder. Text is automatically added to the end indicating that this category is an umbrella category that only contains other categories, and does not contain pages describing terms.

parents

The parent category or categories of the umbrella category. This can either be a single string specifying a category (with or without the Category: prefix), a table with fields name (the category name) and sort (the sort key, as in the outer parents field described above), or a list of either type of entity.

breadcrumb

The last breadcrumb in the chain of breadcrumbs at the top of the category page; see above. By default, this is the category label (i.e. the same as the umbrella category name, minus the final "by language" text).

displaytitle

Apply special formatting such as italics to the umbrella category page title; see above.

topright

Like the topright field on regular category pages; see above.

preceding

Like the preceding field on regular category pages; see above.

additional

Like the additional field on regular category pages; see above.

toc_template, toc_template_full

Override the table of contents bar used on umbrella pages. See below. It's unlikely you will ever need to set this.

umbrella_parents

The same as the parents subfield of the umbrella field. This typically specifies a single umbrella metacategory to which the page's corresponding umbrella page belongs; see #Concepts above). A separate field is provided for this because the umbrella's parent or parents always need to be given, whereas other umbrella properties can usually be defaulted. (In practice, you will find that most entries in a subpage of Module:category tree/data do not explicitly specify the umbrella's parent. This is because a default value is supplied near the end of the "LABELS" section in which the entry is found.)

toc_template

The template or templates to use to display the "table of contents" bar for easier navigation on categories with multiple pages of entries. By default, categories with more than 200 entries or 200 subcategories display a language-appropriate table of contents bar whose contents are held in a template named CODE-categoryTOC, where CODE is the language code of the category's language. (If no such template exists, no table of contents bar is displayed. If the category has no associated language, as with umbrella pages, the English-language table of contents bar is used.) For example, the category Category:Spanish interjections (and other Spanish-language categories) use {{es-categoryTOC}} to display a Spanish-appropriate table of contents bar. (In the case of Spanish, this includes entries for Ñ and for acute-accented vowels such as Á and Ó.) To override this behavior, specify a template or a list of templates in toc_template. The first template that exists will be used; if none of the specified templates exist, the regular behavior applies, i.e. the language-appropriate table of contents bar is selected.

• Special strings such as {{{langcode}}} (to specify the language code of the category's language) can be used in the template names; see below.
• Use the special value false to disable the table of contents bar.
• An example of a category that uses this property is "LANG romanizations". For example, the category Category:Gothic romanizations would by default use the Gothic-specific template {{got-categoryTOC}} to display a Gothic-script table of contents bar. This is inappropriate for this particular category, which contains Latin-script romanizations of Gothic terms rather than terms written in the Gothic script. To fix this, the "romanizations" label specifies a toc_template value of {"{{{langcode}}}-rom-categoryTOC", "en-categoryTOC"}, which first checks for a special Gothic-romanization-specific template {{got-rom-categoryTOC}} (which in this case does exist), and falls back to the English-language table of contents template.

toc_template_full

Similar to toc_template but used for categories with large numbers of entries (specifically, more than 2,500 entries or 2,500 subcategories). If none of the specified templates exist, the templates listed in toc_template are tried, and if none of them exist either, the default behavior applies. In this case, the default behavior is to use a language-appropriate "full" table of contents template named CODE-categoryTOC/full, and if that doesn't exist, fall back to the regular table of contents template named CODE-categoryTOC. An example of a "full" table of contents template is {{es-categoryTOC/full}}, which shows links for all two-letter combinations and appears on pages such as Category:Spanish nouns, with over 50,000 entries.

catfix

Specifies the language code of the language to use when calling the catfix() function in Module:utilities on this page. The catfix() function is used to ensure that page names in foreign scripts show up in the correct fonts and are linked to the correct language.

• The default value is the category's language, if any (for example, the language LANG in pages of the form LANG LABEL). If the category has no associated language, or if the setting catfix = false is used, the catfix mechanism is not applied.
• The setting catfix = false is used, for example, on the romanizations label (which holds Latin-script romanizations of foreign-script terms, rather than terms in the language's native script) and the terms with redundant transliterations labels (which holds pages mentioning terms in the language in question with redundant transliterations). If this is omitted, for example, then pages in Category:Manchu romanizations will show up oriented vertically despite being in Latin script, and pages in Category:Cantonese terms with redundant transliterations will show up using a double-width font despite mostly not being Cantonese-language pages.
• The setting catfix = "en" is used for example on categories of the form Requests for translations into LANG (see Module:category tree/entry maintenance) because these categories contain English pages need translations into a given language, rather than containing pages of that language.
• Note that setting a particular language for catfix will normally cause that language's table of contents page to display in place of the category's normal language, and setting a value of false will normally cause the English table of contents page to display. In both cases, this behavior can be overridden by specifying the toc_template or toc_template_full fields.

|hidden = true

Specifies that the category is hidden. This should be used for maintenance categories. (Hidden categories do not show up in the list of categories at the bottom of a page, but do show up when searched for in the search box.)

|can_be_empty = true

Specifies that the category should not be deleted when empty. This should be used for maintenance categories.

Arbitrary template invocations can be inserted in the text of description, parents (both name and sort key), breadcrumb, toc_template and toc_template_full values, and will be expanded appropriately. In addition, the following special template-like invocations are recognized and replaced by the equivalent text:

{{PAGENAME}}

The name of the current page. (Note that two braces are used here instead of three, as with the other parameters described below.)

{{{langname}}}

The name of the language that the category belongs to. Not recognized in umbrella fields.

{{{langcode}}}

The code of the language that the category belongs to (e.g. en for English, de for German). Not recognized in umbrella fields.

{{{langcat}}}

The name of the language's main category, which adds "language" to the regular name. Not recognized in umbrella fields.

Raw categories are treated similarly to regular labels. The main differences are:

1. They are stored in a separate raw_categories table. The key is the full category name (rather than the label name, as in the case of language categories), and the value is a structure much like for language categories.
2. Raw categories have no corresponding umbrella category, so the umbrella and umbrella_parents fields are unnecessary and do nothing. If you want an umbrella category that groups several related raw categories, you should add the umbrella category yourself as an additional parent (and create a separate entry in the raw_categories table for this umbrella category).

See Module:category tree/modules for an example of a module with several labels and raw categories.

It is also possible to have handlers that can handle arbitrarily-formed labels and raw categories. There are two types of handlers:

1. label handlers handle language categories such as lang ###-syllable words for any lang and ### (e.g. Category:English 3-syllable words), and lang learned borrowings from source for any lang and source (e.g. Category:Spanish learned borrowings from Ancient Greek);
2. raw handlers handle raw categories such as Rhymes:lang/rhyme for any lang and rhyme (e.g. Category:Rhymes:Polish/ajkɛ).

Note that the difference between the two is that label handlers are used for categories prefixed with the language name (and associated umbrella categories, such as Category:3-syllable words by language and Category:Learned borrowings from Ancient Greek by language), while raw handlers are used for arbitrarily-named raw categories. Raw categories may have a language name or code in them (as in the example above), but it generally does not occur as a prefix.

As an example, the following is the label handler for the label terms coined by coiner (such as Category:English terms coined by Lewis Carroll):

table.insert(handlers, function(data)
	local coiner = data.label:match("^terms coined by (.+)$")
	if coiner then
		return {
			description = "{{{langname}}} terms coined by " .. coiner .. ".",
			breadcrumb = coiner,
			umbrella = false,
			parents = {{
				name = "coinages",
				sort = coiner,
			}},
		}
	end
end)

The handler checks if the passed-in label has a recognized form, and if so, returns an object that follows the same format as described above for directly-specified labels. In this case, the handler disables the umbrella category Terms coined by coiner by language because most people coin words in only one language.

The handler is passed a single argument data, which is an object containing the following fields:

1. label: the label;
2. lang: the language object of the language at the beginning of the category, or nil for no language (this happens with umbrella categories);
3. sc: the script code of the script mentioned in the category, if the category is of the form lang label in script, or nil otherwise;
4. args: a table of extra parameters passed to {{auto cat}}.

If the handler interprets the extra parameters passed as data.args, it should return two values: a label object (as described above), and the value true. Otherwise, an error will be thrown if any extra parameters are passed to {{auto cat}}. An example of a handler that interprets the extra parameters is the affix-cat handler in Module:category tree/affixes and compounds, which supports {{auto cat}} parameters |alt=, |sort=, |tr= and |sc=. The |alt= parameter in particular is used to specify extra diacritics to display on the affix that forms part of the category name, as in categories such as Category:Latin terms suffixed with -inus (properly -īnus).

For further examples, see Module:category tree/lexical properties, Module:category tree/terms by script or Module:category tree/etymology.

Raw handlers are similar to label handlers in that they also accept a single argument data, but this object contains only the following fields:

1. category: the raw category;
2. args: a table of extra parameters passed to {{auto cat}}.

Here, there is no language or script object passed in. If there is a language in the category name, it needs to be handled inside of the handler. For example, the following is the raw handler for categories of the form Varieties of lang:

table.insert(raw_handlers, function(data)
	local langname = data.category:match("^Varieties of (.*)$")
	if langname then
		local lang = require("Module:languages").getByCanonicalName(langname)
		if lang then
			return {
				lang = lang:getCode(),
				description = "Categories containing terms in varieties of " .. lang:makeCategoryLink() .. " (regional, temporal, sociolectal, etc.).",
				parents = {
					"{{{langcat}}}",
					{name = "Language varieties", sort = langname},
				},
				breadcrumb = "Varieties",
			}
		end
	end
end)

Note that if a handler is specified, the module should return a table holding both the label and handler data; see the above modules.

Support exists for labels and handlers that are specialized to particular languages. A typical label such as verbs applies to many languages, but some categories have labels that are specialized to a particular language, e.g. Category:Belarusian class 4c verbs or Category:Dutch prefixed verbs with ver-. Here, the label class 4c verbs is specific to Belarusian with a description and other properties only for this particular language, and similarly for the Dutch-specific label prefixed verbs with ver-. Yet, it is desirable to integrate these categories into the category tree hierarchy, so that e.g. breadcrumbs and other features are available. This can be done by creating a module such as Module:category tree/lang/be (for Belarusian) or Module:category tree/lang/nl (for Dutch), and specifying labels and/or handlers in the same fashion as is done for language-agnostic categories. See Module:category tree/lang/documentation for more information. Note that once you create a per-language module, you must add the language code to the langs_with_modules table in Module:category tree/lang listing all the languages with language-specific modules; otherwise, the corresponding categories won't be recognized.