Wikipedia:WikiProject User warnings/Help:Template coding

Template coding guidelines

Parameters

• Default values

  • Nearly all parameters should have a default value, such that misuse does not break the template; exceptions can be made for extra parameters. You can set the default value of a parameter by using piped syntax ({{{1|default value}}}). For example, the template below takes a parameter which expects the user to supply the proper pronoun (she, he, it, they, et cetera).

    {{{1|They}}} are cool.
    Supplied the pronoun with {{template|He}}, the template will expand to "He are cool" (grammar aside). Ignoring the parameter with {{template}}, the template will default the value and expand to "They are cool".
• Expert syntax

  • Where use could conceivably include symbols that break templates (notably the pipe (|) and equals sign (=)), an expert syntax should allow this. In such cases, an expert syntax and simple syntax can coexist as needed. For example, let us say we for some reason want to make a wikilink template.

    [[{{{1}}}]]

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