#### 2.1.4.5 Multiple Escape Characters ¶

A pair of multiple escape characters is used to indicate that an enclosed sequence of characters, including possible macro characters and whitespace_2 characters, are to be treated as alphabetic_2 characters with case preserved. Any single escape and multiple escape characters that are to appear in the sequence must be preceded by a single escape character.

Vertical-bar is a multiple escape character in standard syntax.