Within a tag body, any number of whitespace characters (including line breaks) are coalesced into a single space. Thus, long tag bodies, such as [section], can be broken across multiple lines (the line break is treated as a space). For example…

[section Defining Comparisons with Boolean Operators aka ComparisonsWithBoolOps]

The above is equivalent to (but easier to read than)…

[section Defining Comparisons with Boolean Operators aka ComparisonsWithBoolOps]

The one exception to these rules is the [url] tag.

Sage supports quoted phrases in tag bodies, using either single quote or double quote characters. This feature offers these benefits:

• Allows close square brackets, for example:
  [topic "Lines[index]"].
  Without the quotes, the first close square bracket would end the tag.

• Supports whitespace other than spaces, for example:
  [topic 'A B'].
  Without the quotes, the line break would become a space.

• Supports multiple adjacent whitespace characters, for example:
  [topic 'A B'].
  Without the quotes, multiple adjacent whitespace characters would be coalesced into a single space.

There are two kinds of tags: self-terminating tags and nesting tags. A self-terminating tag is a "one-and-done" affair, such as the [...] tag, which denotes an ellipsis character.

In contrast, a nesting tag has a separate terminating tag, which is nearly always the [end] tag.

For example, the [article] tag defines a Sage article. The tag body contains the article's title. The article's content is everything after the [article] tag, but before the matching [end] tag. Here is an example of a complete article definition:

[article SQL Operators] SQL includes several [i]operators[end], including ... These are discussed in more detail shortly. [end]

Above, note that there are two [end] tags: the first terminates the [i] tag, and the last terminates the [article] tag.

Some Sage tags come in two varieties: one self-terminating and the other nesting. The two varieties will have the same name, except that the self-terminating one will end with a forward slash. For example, Sage offers the [url/] (self-terminating) and [url] (nesting) tags. We use the self-terminating tag when the desired caption is simply the URL, and we use the nesting tag when we need to specify a different caption. For example:

The [url/] tag is more concise, but [url]…[end] is useful when the link's caption needs to be something different from the URL itself, and/or benefits from some formatting or other Sage markup.

The remainder of this topic discusses Sage tags in detail, however, for a quick overview, see the tag reference chart.