Editing Template:Category handler/doc (section)

=== Advanced usage ===

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

<pre>
{{mbox
| text = This is a box for articles and talk pages.
}}{{category handler
| main = [[Category:Somecat1]]   <!--Categorize in main (article) space-->
| talk = [[Category:Somecat2]]   <!--Categorize in talk space-->
| nocat = {{{nocat|}}}   <!--So "nocat=true" works-->
}}
</pre>

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

<pre>
== My new template ==
Hey guys, have you seen my new template?
{{mytemp|nocat=true}}
Nice, isn't it?
--~~~~
</pre>

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

<pre>
{{mbox
| text = This is a box used in several namespaces.
}}{{category handler
| 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 = {{{nocat|}}}   <!--So "nocat=true/false" works-->
}}
</pre>

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

This template understands the numbered parameters 1 to 10.

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 template from showing what has been fed to the '''other''' parameter, when in talk space.

This template also has a parameter called '''all'''. It works like this:

<pre>
{{mbox
| text = This is a box used in all namespaces.
}}{{category handler
| all = [[Category:Somecat1]]   <!--Categorize in all namespaces-->
| nocat = {{{nocat|}}}   <!--So "nocat=true/false" works-->
}}
</pre>

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

We suggest avoiding the '''all''' parameter, since 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:

<pre>
{{mbox
| text = This is a box used in all namespaces.
}}{{category handler
| 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 = {{{nocat|}}}   <!--So "nocat=true/false" works-->
}}
</pre>

If the above box 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.