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Bison Declarations

The Bison declarations section of a Bison grammar defines the symbols used in formulating the grammar and the data types of semantic values. See Symbols.

All token type names (but not single-character literal tokens such as '+' and '*') must be declared. Nonterminal symbols must be declared if you need to specify which data type to use for the semantic value (see More Than One Value Type).

The first rule in the file also specifies the start symbol, by default. If you want some other symbol to be the start symbol, you must declare it explicitly (see Languages and Context-Free Grammars).

• Token Decl: Declaring terminal symbols.
• Precedence Decl: Declaring terminals with precedence and associativity.
• Union Decl: Declaring the set of all semantic value types.
• Type Decl: Declaring the choice of type for a nonterminal symbol.
• Expect Decl: Suppressing warnings about shift/reduce conflicts.
• Start Decl: Specifying the start symbol.
• Pure Decl: Requesting a reentrant parser.
• Decl Summary: Table of all Bison declarations.