Text representing code is presented in a fixed-width font. Text in code that is intended to be replaced, or representing a class of possible values are presented in italics.
The sections on syntax make extensive use of railroad diagrams, a common method of describing syntax. Each smooth path from the start of the diagram to the end, including loop-backs, represents a syntactically valid piece of code. Literal text is represented in round boxes in a fixed-width font. Square boxes with a san-serif font represent a subdiagram. The values in round boxes are called terminals, while those in square boxes are called non-terminals.