Module:Check for unknown parameters/doc

This module may be appended to a template to check for uses of unknown parameters.

Basic usage
or to sort the entries in the tracking category by parameter with a preview error message

or for an explicit red error message

Here,,  , ...,  , are the known parameters. Any parameter which is used, but not on this list, will cause the module to return whatever is passed with the  parameter. The  keyword, if used, will be changed to the name of the parameter. This is useful for either sorting the entries in a tracking category, or for provide more explicit information.

By default, the module makes no distinction between a defined-but-blank parameter and a non-blank parameter. To only track non-blank parameters use 1.

By default, the module ignores blank positional parameters. To include blank positional parameters in the tracking use 1.

Include reason
Unless there's a very good reason not to, the parameter  should always be supported. This is used as a de facto standard, across all templates, as a way to include an explanatory note (e.g., why the template was placed, in any case in which that isn't obvious) without affecting the displayed output in any way (usually). If you do not include  among permissible values, then this module with throw a bogus error when people include a reason. A few templates (e.g. ) directly implement a reason parameter that actually does something, but it most cases it is a pseudo-parameter that does not actually appear in the template code, and is used in lieu of messy HTML comments.

Lua patterns
This module supports Lua patterns (similar to regular expressions), which are useful when there are many known parameters which use a systematic pattern. For example, template:infobox3cols uses to match all parameters of the form,  ,  ,  ,  ,  , ...,  , where NUM is a string of digits.
 * regexp1 = header[%d][%d]*
 * regexp2 = label[%d][%d]*
 * regexp3 = data[%d][%d]*[abc]?
 * regexp4 = class[%d][%d]*[abc]?
 * regexp5 = rowclass[%d][%d]*
 * regexp6 = rowstyle[%d][%d]*
 * regexp7 = rowcellstyle[%d][%d]*

Templates invoking this module
The following is a list of some of the templates which invoke this module, with the associated category for each.

For a more up-to-date list, [//en.wikipedia.org/w/index.php?title=Special:Search&limit=500&offset=0&ns10=1&search=insource%3A%2FCheck+for+unknown+parameters%2F search for the "check for unknown parameters" within the template namespace].