Module:Category handler/doc

This module implements the {{category handler}} template. The category handler template helps other templates to automate both categorization and category suppression. For information about using the category handler template in other templates, please see the template documentation. Keep reading for information about using the category handler module in other Lua modules, or for information on exporting this module to other wikis.

Use from other Lua modules

When not to use this module

For cases where a module only needs to categorise in one of the namespaces main (articles), file (images) or category, then using this module is overkill. Instead, you can simply get a title object using mw.title.getCurrentTitle and check the nsText field. For example:

local title = mw.title.getCurrentTitle
if title.nsText == 'File' then
    -- do something
end

However, if your module needs to categorize in any other namespace, then we recommend you use module, since it provides proper category suppression and makes it easy to select how to categorize in the different namespaces.

Namespaces

This module detects and groups all the different namespaces used on Wikipedia into several types. These types are used as parameter names in this module.

main = Main/article space, as in normal Wikipedia articles.

talk = Any talk space, such as page names that start with "Talk:", "User talk:", "File talk:" and so on.

user, wikipedia, file ... = The other namespaces except the talk pages. Namespace aliases are also accepted. See the table below for the full list.

other = Any namespaces that were not specified as a parameter to the template. See examples below.

List of possible namespace parameters

(excluding talk and other)

Namespace	Aliases
main
user
wikipedia	project, wp
file	image
mediawiki
template
help
category
mos
timedtext
module

Basic usage

This module takes two or more parameters. Here's an example using a hello world program:

p = {}
local categoryHandler = require( 'Module:Category handler' ).main
 
function p.main( frame )
    local result = 'Hello world!'
    local category = categoryHandler{
        '[[Category:Somecat]]',
        nocat = frame.args.nocat -- So "nocat=true/false" works
    }
    category = category or '' -- Check that we don't have a nil value for the category variable.
    return result .. category
end
 
return p

The above example uses the default settings for the category handler module. That means the example module will categorize on pages in the following namespaces:

main, file, help, category, portal and book

But it will not categorize in any other namespaces, e.g.:

talk, user, wikipedia, mediawiki, template ...

And it will not categorize on blacklisted pages. (See section blacklist below.)

The reason the category handler module does not categorize in some of the namespaces is that in those namespaces most modules and templates are just demonstrated or listed, not used. Thus most modules and templates should not categorize in those namespaces.

Any module or template that is meant for one or more of the namespaces where this module categorizes can use the basic syntax as shown above.

Advanced usage

This module takes one or more parameters named after the different page types as listed in section namespaces above. By using those parameters you can specify exactly in which namespaces your template should categorize. Like this:

p = {}
local categoryHandler = require( 'Module:Category handler' ).main
 
function p.main( frame )
    local result = 'This is a module meant for articles and talk pages.'
    local category = categoryHandler{
        main = '[[Category:Somecat1]]', -- Categorize in main (article) space
        talk = '[[Category:Somecat2]]', -- Categorize in talk space
        nocat = frame.args.nocat -- So "nocat=true/false" works
    }
    category = category or '' -- Check that we don't have a nil value for the category variable.
    return result .. category
end
 
return p

The above module will only categorize in main and talk space. But it will not categorize on /archive pages since they are blacklisted. (See section blacklist below.) And if you need to demonstrate (discuss) the module on a talkpage, then you can feed "nocat='true'" to prevent that template from categorizing. (See section nocat below.) Like this:

== My new module ==
Hey guys, have you seen my new module?
{{#invoke:mymodule|main|nocat=true}}
Nice, isn't it?
--~~~~

Sometimes we want to use the same category in several namespaces, then do like this:

p = {}
local categoryHandler = require( 'Module:Category handler' ).main
 
function p.main( frame )
    local result = 'This is a module used in several namespaces.'
    local category = categoryHandler{
        main = '[[Category:Somecat1]]',
        [ 1 ] = '[[Category:Somecat2]]', -- For help and user space
        help = 1,
        user = 1,
        talk = '', -- No categories on talk pages
        other = '[[Category:Somecat3]]', -- For all other namespaces
        nocat = frame.args.nocat -- So "nocat=true/false" works
    }
    category = category or '' -- Check that we don't have a nil value for the category variable.
    return result .. category
end
 
return p

In the above example we use a numbered parameter to feed one of the categories, and then we tell this module to use that numbered parameter for both the help and user space.

The category handler module understands an unlimited number of numbered parameters.

The other parameter defines what should be used in the remaining namespaces that have not explicitly been fed data.

Note the empty but defined talk parameter. That stops this module from showing what has been fed to the other parameter, when in talk space.

The category handler module also has a parameter called all. It works like this:

p = {}
local categoryHandler = require( 'Module:Category handler' ).main
 
function p.main( frame )
    local result = 'This is a module used in all namespaces.'
    local category = categoryHandler{
        all = '[[Category:Somecat1]]', -- Categorize in all namespaces
        nocat = frame.args.nocat -- So "nocat=true/false" works
    }
    category = category or '' -- Check that we don't have a nil value for the category variable.
    return result .. category
end
 
return p

The above example will categorize in all namespaces, but not on blacklisted pages. If you want to demonstrate that module on a page, then use "nocat=true" to prevent the template from categorizing.

We suggest avoiding the all parameter, since modules and templates should preferably only categorize in the namespaces they need to.

The all parameter can also be combined with the rest of the parameters. Like this:

p = {}
local categoryHandler = require( 'Module:Category handler' ).main
 
function p.main( frame )
    local result = 'This is a module used in all namespaces.'
    local category = categoryHandler{
        all = '[[Category:Somecat1]]', -- Categorize in all namespaces
        main = '[[Category:Somecat2]]', -- And add this in main space
        other = '[[Category:Somecat3]]', -- And add this in all other namespaces
        nocat = frame.args.nocat -- So "nocat=true/false" works
    }
    category = category or '' -- Check that we don't have a nil value for the category variable.
    return result .. category
end
 
return p

If the above module is placed on an article, then it will add the categories "Somecat1" and "Somecat2". But on all other types of pages it will instead add "Somecat1" and "Somecat3". As the example shows, the all parameter works independently of the rest of the parameters.

Exporting to other wikis

This module can be exported to other wikis by changing the configuration values in the cfg table. All the variable values are configurable, so after the configuration values have been set there should be no need to alter the main module code. Details of each configuration value are included in the module code comments. In addition, this module requires Module:Namespace detect to be available on the local wiki.