Include content only once

Use singleton to wrap contents (tag, text, HTML, or lists) that should be included in the generated document only once, yet may appear in the document-generating code more than once. Only the first appearance of the content (in document order) will be used.

singleton(x, value = TRUE)

is.singleton(x)

Arguments

x

A tag(), text, HTML(), or list.

value

Whether the object should be a singleton.