def dateFormat = { attrs, body ->
    out << new java.text.SimpleDateFormat(attrs.format).format(attrs.date)
}8.3.2 Simple Tags
Version: 3.2.0
8.3.2 Simple Tags
As demonstrated in the previous example it is easy to write simple tags that have no body and just output content. Another example is a dateFormat style tag:
The above uses Java’s SimpleDateFormat class to format a date and then write it to the response. The tag can then be used within a GSP as follows:
<g:dateFormat format="dd-MM-yyyy" date="${new Date()}" />With simple tags sometimes you need to write HTML mark-up to the response. One approach would be to embed the content directly:
def formatBook = { attrs, body ->
    out << "<div id=\"${attrs.book.id}\">"
    out << "Title : ${attrs.book.title}"
    out << "</div>"
}Although this approach may be tempting it is not very clean. A better approach would be to reuse the render tag:
def formatBook = { attrs, body ->
    out << render(template: "bookTemplate", model: [book: attrs.book])
}And then have a separate GSP template that does the actual rendering.