Comments in XQuery

Comments are allowed in an XQuery expression, wherever nonessential whitespace is allowed. Comments do not affect expression processing.

(: This is a comment. It makes code easier to understand. :)

The following general rules apply to using comments in XQuery:

• Comments can be used wherever nonessential whitespace is allowed. Nonessential whitespace is whitespace that is not part of the syntax of an XQuery expression.
• Comments can nest within each other, but each nested comment must have open and close delimiters, (: and :).

The following examples illustrate legal comments and comments that result in errors:

• (: is this a comment? ::) is a legal comment.
• (: is this a comment? ::) or an error? :) results in an error because there is an unbalanced nesting of the symbols (: and :).
• (: commenting out a (: comment :) may be confusing, but often helpful :) is a legal comment because a balanced nesting of comments is allowed.
• "this is just a string :)" is a legal expression.
• (: "this is just a string :)" :) results in a syntax error. Likewise, "this is another string (:" is a legal expression, but (: "this is another string (:" :) results in a syntax error. Literal content can result in an unbalanced nesting of comments.