EXPRESS Syntax
Douglas Schenck, Peter Wilson · Oxford University Press eBooks · 1994
Here is the entire syntax except for constant tokens (i.e., reserved words and such), character sets, standard constants, functions and procedures, and simple equates to tokens that create or reference identifiers. The following conventions will help to interpret the syntax presentation: • Identifiers written in upper case letters are keywords of the language. For example, when you see SCHEMA this means that the word ‘schema’ must be written at this place (using mixed case if you wish.) The names of these syntax productions are identical to the keywords of the language. • Elements that follow the pattern xxxDef represent an identifier declaration. For example, VarDef shows where a variable declaration takes place. This also implies that the name created at this place is subject to the scoping rules that apply to the object in question. • Elements that follow the pattern xxxRef represent a reference to some explicit definition. For example, a VarRef requires a VarDef.