2. Source text and grammar notation

2.1. Source text

Source text is a sequence of Unicode scalar values.

The language is case-sensitive.

Diagnostics MUST identify the range of source text to which they apply.

2.2. Grammar notation

The grammar in this specification uses the following notation:

• quoted text denotes a token;
• ? denotes an optional production;
• * denotes zero or more repetitions;
• + denotes one or more repetitions;
• | separates alternatives;
• parentheses group productions.

Where the precedence table and a grammar summary overlap, the precedence table determines expression grouping.