How to Read a Syntax Diagram

Syntax is described using the structure defined below.

Read the syntax diagrams from left o right, from top to bottom, following the path of the line.
The ►►─── symbol indicates the beginning of a macro syntax.

The ───► symbol indicates that the macro syntax is continued on the next line.

The ►─── symbol indicates that the macro syntax is continued from the previous line.

The ───►◄ indicates the end of the macro syntax.

A lower-case word indicates a variable.
Required keywords (and their value) and required positioinal items appear on the horizontal line (the main path).
Required Items
>>-positional_item--,required_item--,KEYWORD=--required_value--><

Optional keywords (and their value) and posiitonal items appear below the main path.

Optional Items
>>-+---------------+--+--------------------------+------------->< '-optional_item-' '-,KEYWORD=--optional_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.
Required Choice
>>-+-positional_choice1-+--,KEYWORD=--+-required_choice1-+----->< '-positional_choice2-' '-required_choice2-'

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

Optional Choice
>>-positional_item--+-------------------+---------------------->< +-,optional_choice1-+ '-,optional_choice2-'

If one of the items has a default, it appears above the main line (for that item) and the overriding choices will be shown on and/or below the main line. For POSITIONAL items the syntax is as follows:

Default Positional Item


>>-+----------------------------+------------------------------><
   |                      (1)   |   
   | .-positional_default-----. |   
   '-+-positional_option1-----+-'   
     |                    (2) |     
     '-positional_option2-----'

Notes:

If a positional parameter is not specified, the positional default is used
If a positional parameter is coded, then any one of the 3 positional parameters can be specified.

For KEYWORD items the syntax is as follows:

Default Keyword Item


>>-+-----------------------------------+-----------------------><
   |                             (1)   |   
   |           .-keyword_default-----. |   
   '-KEYWORD=--+-keyword_value1------+-'   
               |                (2)  |     
               '-keyword_value2------'

Notes:

If KEYWORD is not coded, the keyword_default is used.
If the KEYWORD is coded, then the keyword_default or the keyword value override MUST be coded.

An arrow returning to the left above the main line indicates an item that can be repeated indefinitiely.

Indefinitely Repeated Item
.-,-------------------. V \| >>-KEYWORD------repeatable_item---+----------------------------><

A repeat arrow with a syntax note indicates how many times this can be repeated.

Fixed Repeated Item


            .-,-------------------.       
            V                     | (1)   
>>-KEYWORD------repeatable_item---+----------------------------><

Notes:

(1) Specify the <repeatable_item> 1 to n times.

Syntax is occasionally broken into fragments if the inclusion of the fragment would overly complicate the main syntax diagram.

Fragment


>>-KEYWORD--| fragment |---------------------------------------><

fragment

|--+-----------------------------------------+------------------|
   +-,optional_choice1-----------------------+   
   |                    .-default_choice---. |   
   '-,optional_choice2--+------------------+-'   
                        '-,optional_choice-'