ECMAScript 4 Netscape Proposal Formal Description

Wednesday, August 14, 2002

• Semantic Notation
• Stages
• Lexical Grammar Summary (also available as Word RTF)
• Lexical Grammar and Semantics (Word RTF)
• Regular Expression Grammar Summary (Word RTF)
• Regular Expression Grammar and Semantics (Word RTF)
• Syntactic Grammar Summary (Word RTF)
• Syntactic Grammar and Semantics (Word RTF)

This chapter presents the formal syntax and semantics of ECMAScript 4. The syntax notation and semantic notation sections explain the notation used for this description. A simple metalanguage based on a typed lambda calculus is used to specify the semantics.

The syntax and semantic sections are available in both HTML 4.0 and Microsoft Word RTF formats. In the HTML versions each use of a grammar nonterminal or metalanguage value, type, or field is hyperlinked to its definition, making the HTML version preferred for browsing. On the other hand, the RTF version looks much better when printed. The fonts, colors, and other formatting of the various grammar and semantic elements are all encoded as CSS (in HTML) or Word (in RTF) styles and can be altered if desired.

The syntax and semantics sections are machine-generated from code supplied to a small engine that can type-check and execute the semantics directly. This engine is in the CVS tree at mozilla/js2/semantics; the input files are at mozilla/js2/semantics/JS20.

Waldemar Horwat Last modified Wednesday, August 14, 2002