Special syntax characters like tabs or parathesises can be embedded by escapes.

For example, the tab character is \t and a left-parens is \(

Certain classes of characters are escapes:

• \d is any decimal digit and \D is any non-decimal digit

• \s is a whitespace character and \S is any non-whitespace character.

• \w is any character not considered punctuation, separators, or other by Unicode and \W is the opposite.

See page 187-188 for more information.