How to read syntax diagrams

Throughout this publication, syntax is described in diagrams like the one shown here, which describes the SRSTAT TSO command:

>>---SRSTAT----'--resource name--'------------------------------>
 
>--+------------------------------+--+--------------------+----->
   |         .-OPCA-----------.   |  |        .-KEEP--.   |
   '-SUBSYS(-+-subsystem name-+-)-'  '-AVAIL(-+-RESET-+-)-'
             '-MSTR-----------'               +-NO----+
                                              '-YES---'
 
>--+-------------------------+--+------------------------+------>
   |            .-KEEP---.   |  |           .-KEEP---.   |
   '-DEVIATION(-+-amount-+-)-'  '-QUANTITY(-+-amount-+-)-'
                '-RESET--'                  '-RESET--'
 
>--+-------------------+--+--------------------------+---------><
   |         .-YES-.   |  |        .-0-----------.   |
   '-CREATE(-+-NO--+-)-'  '-TRACE(-+-trace level-+-)-'

The symbols have these meanings:

>>-----: The statement begins here.
------>: The statement is continued on the next line.
>------: The statement is continued from a previous line.
-----><: The statement ends here.

Read the syntax diagrams from left to right and from top to bottom, following the path of the line.

These are the conventions used in the diagrams:

Required items appear on the horizontal line (main path):

>>-STATEMENT--required item------------------------------------><

Optional items appear below the main path:

>>-STATEMENT--+---------------+--------------------------------><
              '-optional item-'

An arrow returning to the left above the item indicates an item that you can repeat. If a separator is required between items, it is shown on the repeat arrow.
```
              .-,---------------.
              V                 |
>>-STATEMENT----repeatable item-+------------------------------><
 
```

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:

>>-STATEMENT--+-required choice 1-+----------------------------><
              '-required choice 2-'

If choosing one of the items is optional, the entire stack appears below the main path:

>>-STATEMENT--+-------------------+----------------------------><
              +-optional choice 1-+
              '-optional choice 2-'

A repeat arrow above a stack indicates that you can make more than one choice from the stacked items:

              .-,---------------------.
              V                       |
>>-STATEMENT----+-------------------+-+------------------------><
                +-optional choice 1-+
                +-optional choice 2-+
                '-optional choice 3-'

              .-,---------------------.
              V                       |
>>-STATEMENT----+-required choice 1-+-+------------------------><
                +-required choice 2-+
                '-required choice 3-'

Parameters that are above the main line are default parameters:

              .-default-----.
>>-STATEMENT--+-------------+----------------------------------><
              '-alternative-'

Keywords appear in uppercase (for example, STATEMENT).
Parentheses and commas must be entered as part of the command syntax, as shown.

For complex commands, the item attributes might not fit on one horizontal line. If that line cannot be split, the attributes appear at the bottom of the syntax diagram:

>>-STATEMENT---------------------------------------------------->
 
>--+-required choice 1--+--------------+--+--------------+-+---><
   |                    '-| option 1 |-'  '-| option 2 |-' |
   +-required choice 2-------------------------------------+
   '-required choice 3-------------------------------------'
 
option 1
 
                      .-default-----.
|--optional choice 1(-+-alternative-+-)-------------------------|
 
option 2
 
                      .-default-----.
|--optional choice 2(-+-alternative-+-)-------------------------|