Introduction › Reading Syntax Diagrams

Reading Syntax Diagrams

Syntax diagrams are used to illustrate the format of statements and some basic language elements. Read syntax diagrams from left to right and top to bottom.

The following terminology, symbols, and concepts are used in syntax diagrams:

• Keywords appear in uppercase letters, for example, COMMAND or PARM. These words must be entered exactly as shown.
• Variables appear in italicized lowercase letters, for example, variable.
• Required keywords and variables appear on a main line.
• Optional keywords and variables appear below a main line.
• Default keywords are indicated with a single arrowhead pointing to the left.
• Double arrowheads pointing to the right indicate the beginning of a statement.
• Double arrowheads pointing to each other indicate the end of a statement.
• Single arrowheads pointing to the right indicate a portion of a statement, or that the statement continues in another diagram.
• Punctuation marks or arithmetic symbols that are shown with a keyword or variable must be entered as part of the statement or command. Punctuation marks and arithmetic symbols can include the following: