Grammar notation

This language specification adopts a flavor of Backus-Naur Form (BNF) to describe the syntax of language features.

SPL uses the following conventions:

Table 1. Notations used in SPL

Notations	Meaning
Italics	Non-terminal.
ALL_CAPS_ITALICS	Token. For example, ID for identifiers.
'fixed-width font'	Verbatim text that is quoted to avoid confusion with meta-characters. For example: '('
(...)	Grouping - to disambiguate meta-syntax precedence.
... | ...	Alternatives - to match syntax on either left or right of the bar.
...?	The syntax that precedes this notation is optional.
...*	The syntax that precedes this notation is repeated zero or more times.
...+	The syntax that precedes this notation is repeated one or more times.
...*,	Comma-separated list of zero or more items.
...+,	Comma-separated list of one or more items.
...*;	Semicolon separated list of zero or more items.
...+;	Semicolon separated list of one or more items.
...+.	Period separated list of one or more items.
nonTerminal ::= ...	Rule definition.