This specification uses an extended Backus Normal Form (BNF) to describe the syntax of Common Lisp macro forms and special forms. This section discusses the syntax of BNF expressions.
1.4.1.2.1 Splicing in Modified BNF Syntax
1.4.1.2.2 Indirection in Modified BNF Syntax
1.4.1.2.3 Additional Uses for Indirect Definitions in Modified BNF Syntax