A.3 Syntax Notation

In the syntax notation used in this manual, syntactic categories are indicated by italic type, and literal words and characters in typewriter style. Alternative categories are usually listed on separate lines; in a few cases, a long set of narrow alternatives is presented on one line, marked by the phrase ``one of.'' An optional terminal or nonterminal symbol carries the subscript ``opt,'' so that, for example,

{ expressionopt }

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means an optional expression, enclosed in braces. The syntax is summarized in Par.A.13.

Unlike the grammar given in the first edition of this book, the one given here makes precedence and associativity of expression operators explicit.