(Quick Reference) ### Tag Library Usage A tag library fulfills role of "view helper" in the Model View Controller (MVC) pattern and helps with GSP rendering. In Grails a tag library is a class with a name that ends in the convention "TagLib" and lives in the `grails-app/taglib` directory. Use the create-taglib command to create a tag library:
    grails create-taglib format
or with your favourite IDE or text editor make a new file with the name `FormatTagLib` in `grails-app/taglib` as given below
    import java.text.SimpleDateFormat

    class FormatTagLib {
        def dateFormat = { attrs, body ->
            out << new SimpleDateFormat(attrs.format).format(attrs.value)
        }
    }
Each Closure property in a tag library that takes one or two arguments is considered a tag. The first argument (typically named `attrs`) will contain the attributes of the tag whilst the optional second argument (typically named `body`) is Closure that represents the inner HTML of the tag declaration from the GSP. Refer to the user guide topic on Tag Libraries for more information. | Quick Reference (hide)