The following table describes the meaning of symbols used in railroad diagrams.
| Symbol | Definition |
|---|---|
 | Statement begins here. |
 | Statement continues on next line. |
 | Statement is continued from previous line. |
 | Statement ends here. |
 | Alternatives: optionally select one keyword. Boldface indicates default if no selection is made. |
 | Alternatives: selection of one keyword is required. |
 | A comma-separated list of any length is permitted. |
 | Word is not further defined. Replace with value of format shown in the Terminals table. |
 | Word used in statement is further defined. |
 | Non-terminal used in statements is defined here. |