This chapter gives a short overview of the Extended Backus-Naur Form (EBNF) notation, which is frequently used in this document to describe file formats and syntax rules.
ProcDecl = PROCEDURE ( ArgList ). ArgList = Expression {, Expression}. Expression = Term (*|/) Term. Term = Factor AddOp Factor. AddOp = +|-. Factor = ([-] Number)|( Expression ).
The EBNF notation is used to express the syntax of context-free languages. The EBNF grammar consists of a rule set called productions of the form:
LeftHandSide = RightHandSide.
The left-hand side is a non-terminal symbol. The right-hand side describes the composition.
EBNF consists of the following symbols. A brief discussion of each symbol follows.