User:Techhead7890/substitution

When substituting a template it may be desirable to carry out a substitution inside the template too. This can be done with "safesubst:" in the template. However, the code is written in as default value of an unused parameter, in order to prevent premature substitution (such as when the template itself is saved). When choosing the name of the parameter, the empty string is often used. While the empty string is a possible parameter name, it is rarely used for other purposes — so it is usually a suitable choice for the name of this unused parameter, so we can use the code. Assuming the parameter with the empty string as name is undefined, when evaluated,  will evaluate back to.