Terminal symbols are shown in
fixed width font in the productions of the lexical and syntactic grammars, and throughout this specification whenever the text is directly referring to such a terminal symbol. These are to appear in a program exactly as written.
Nonterminal symbols are shown in italic type. The definition of a nonterminal is introduced by the name of the nonterminal being defined followed by a colon. One or more alternative right-hand sides for the nonterminal then follow on succeeding lines.
For example, the syntactic definition:
if ( Expression
states that the nonterminal IfThenStatement represents the token
if, followed by a left parenthesis token, followed by an Expression ...