Special Symbols

IDL documentation uses the following symbolic notations:

[item] Italic brackets surrounding an item indicate that the item is optional.

[item] Brackets shown in regular typeface are a required part of the syntax.

item ... Ellipsis points following an item indicate that the item may occur one or more times.

item , ... If an item is followed by a literal punctuation character and then by ellipsis points, the item may occur either once without the punctuation character, or more than once with the punctuation character separating each instance.

... If ellipsis points are shown on a line by themselves, the item or set of items in the preceding line may occur any number of additional times.

item | item If several items are shown separated by vertical bars, exactly one of those items must occur.

[item]	Italic brackets surrounding an item indicate that the item is optional.
[item]	Brackets shown in regular typeface are a required part of the syntax.
item ...	Ellipsis points following an item indicate that the item may occur one or more times.
item , ...	If an item is followed by a literal punctuation character and then by ellipsis points, the item may occur either once without the punctuation character, or more than once with the punctuation character separating each instance.
...	If ellipsis points are shown on a line by themselves, the item or set of items in the preceding line may occur any number of additional times.
item \| item	If several items are shown separated by vertical bars, exactly one of those items must occur.