Use the following description to read the
syntax diagrams in this information:
- 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 syntax diagram.
The ---> symbol
indicates that the syntax diagram is continued on the next line.
The
>--- symbol indicates that the syntax diagram is continued
from the previous line.
The --->< symbol indicates
the end of a syntax diagram.
Diagrams of syntactical units
other than complete statements start with the >--- symbol
and end with the ---> symbol.
- Required
items appear on the horizontal line (the main path).

Format
>>-STATEMENT--required item------------------------------------><
- Optional
items appear below the main path.

Format
>>-STATEMENT--+---------------+--------------------------------><
'-optional item-'
- When 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.

Format
>>-STATEMENT--+-required choice 1-+----------------------------><
'-required choice 2-'
If choosing one of the items is optional,
the entire stack appears below the main path.

Format
>>-STATEMENT--+-------------------+----------------------------><
+-optional choice 1-+
'-optional choice 2-'
- An arrow
returning to the left above the main line indicates an item that can
be repeated.

Format
.-----------------.
V |
>>-STATEMENT----repeatable item-+------------------------------><
A repeat arrow above a stack indicates that
you can make more than one choice from the stacked items, or repeat
a single choice.
- Variables appear in italic lowercase letters (for example, parmx).
They represent user-supplied names or values.
- If punctuation marks, parentheses, arithmetic operators, or other
such symbols are shown, they must be entered as part of the syntax.