C++ In a Nutshell

Chapter 12. Language Reference

Here begins the alphabetic reference. This chapter presents each language keyword with a syntax summary, description, and, in some cases, an example. The syntax summaries use a modified BNF (Backus Normal Form or Backus-Naur Form):

• Terminal symbols (keywords and operator symbols) are in a constant-width typeface.

• To avoid ambiguity, a terminal symbol that might be mistaken for a BNF metacharacter (e.g., a vertical bar or a square bracket) is enclosed in quotes (e.g., "|“).

• Nonterminal symbols (syntax elements) are in an italic typeface.

• Optional elements are in square brackets ([ like this ]).

• Choices are separated by vertical bars (|).

• A production (syntax description) is introduced with := or ::=. The traditional symbol (::=) is used for a complete definition. The abbreviated symbol (:=) is used when the righthand side is incomplete. For example, here is the complete definition of function-specifier as it is given under declaration:

  function-specifier ::= explicit | inline | virtual

  The following is a partial production of function-specifier:

  function-specifier := inline

  The abbreviated symbol (:=) lets you see that the syntax summary is incomplete. Whenever an incomplete rule is used, a cross reference (under “See Also”) leads you to the complete rule.

The starting point for parsing a C++ source file (the start symbol) is translation-unit, which you can find under declaration.

C++ syntax is complicated, and even simple statements require an understanding of ...