In the syntax notation used in this document, syntactic
categories are indicated by
italic type, and literal words
and characters in
constant width type
. Alternatives are
listed on separate lines except in a few cases where a long set of
alternatives is marked by the phrase “one of”
. If the text of an alternative is too long to fit on a line, the text is continued on subsequent lines indented from the first one
. An optional terminal or non-terminal symbol is indicated by the subscript
“
opt”, so
indicates an optional expression enclosed in braces
.