Template:Voidd/doc

This template can be used for monitoring parameter usage.

Monitoring parameter usage
To monitor the usage of a parameter of a template (in the case that many pages use the template), this template can call an auxiliary template of which the name depends on whether the parameter is defined. The possible auxiliary templates need not exist, if they are e.g. used as parameter value of voidd, to avoid displaying anything (with the new preprocessor void cannot be used for this anymore). Applying "What links here" to the possible auxiliary templates shows which pages use the template with the parameter, and which pages use the template without the parameter. This parameter usage monitor facility should preferably be built into the template when creating the template or introducing a new parameter. If it is done afterwards "What links here" may not show a page until it has been refreshed by an ordinary or dummy edit or purge. Applications of monitoring parameter usage include:
 * check where the parameter has not yet been specified, in order to add it
 * check where a parameter is used that is renamed, in order to change the template calls
 * check whether a parameter is used before abolishing it
 * when a template has been changed with respect to processing a particular parameter, check the pages which use the parameter (or some of them) to see if things work as desired.

In a similar way an auxiliary template can be called for a "template / parameter / parameter value" combination or "template / parameter /  parameter value range" combination. "What links here" then shows which pages use the template with this parameter value, or with the parameter in the given range.

See.

Testing (?)
pq

Special:Whatlinkshere/Template:Tc