How to read the syntax diagrams

Function syntax is described using the structure defined below.
  • Read the syntax diagrams from left to right, from top to bottom, following the path of the line.

    The ►►─── symbol indicates the beginning of a statement.

    The ───► symbol indicates that a statement is continued on the next line.

    The ►─── symbol indicates that a statement is continued from the previous line.

    The ───►◄ symbol indicates the end of a statement.

  • Required items appear on the horizontal line (the main path).
    Read syntax diagramSkip visual syntax diagram
    >>-STATEMENT--required_item------------------------------------><
    
    
  • Optional items appear below the main path.
    Read syntax diagramSkip visual syntax diagram
    >>-STATEMENT--+---------------+--------------------------------><
                  '-optional_item-'   
    
    
  • If a default value is provided for an item (that is, if no parameter is specified, the default is used), the default item appears above the main path.
    Read syntax diagramSkip visual syntax diagram
                  .-default_item-.   
    >>-STATEMENT--+--------------+---------------------------------><
    
    
  • If you can choose from two or more items, they appear vertically, in a stack.
    If you must choose one of the items, one item of the stack appears on the main path.
    Read syntax diagramSkip visual syntax diagram
    >>-STATEMENT--+-required_choice1-+-----------------------------><
                  '-required_choice2-'   
    
    
    If choosing one of the items is optional, the entire stack appears below the main path.
    Read syntax diagramSkip visual syntax diagram
    >>-STATEMENT--+------------------+-----------------------------><
                  +-optional_choice1-+   
                  '-optional_choice2-'   
    
    
    If choosing an item is optional, but when no selection is made, the default is used, the default appears above the line and the remaining optional choices below the line.
    Read syntax diagramSkip visual syntax diagram
                  .-default_item--.   
    >>-STATEMENT--+---------------+--------------------------------><
                  '-optional_item-'   
    
    
  • An arrow returning to the left above the main line indicates an item that can be repeated.
    Read syntax diagramSkip visual syntax diagram
                  .-----------------.   
                  V                 |   
    >>-STATEMENT----repeatable_item-+------------------------------><
    
    
  • Keywords (for example, INPUT) appear in uppercase letters. They must be spelled exactly as shown.
  • Variables (for example, nlrecs) appear in lowercase letters. They represent user-supplied names or values.

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