Brendan Eich wrote: [...] > If you make the /= correction, there is no ambiguity.
Indeed there is no ambiguity; I think Allen's point is that the spec is currently written in a way that is very unhelpful in allowing one to conclude that. > 7.1 last paragraph: > > Note that contexts exist in the syntactic grammar where both a division > and a RegularExpressionLiteral are permitted by the syntactic grammar; I believe that statement is wrong. I gave a detailed argument for why it is wrong at <http://www.mail-archive.com/[email protected]/msg01329.html>; the only reply was by Eric Suen, and the argument in his post was incorrect. I'll repeat my argument here for convenience: A DivisionPunctuator must be preceded by an expression. A RegularExpressionLiteral is itself an expression. (This assumes that the omission of RegularExpressionLiteral from Literal is a bug.) Therefore, for there to exist syntactic contexts in which either a DivisionPunctuator or a RegularExpressionLiteral could occur, it would have to be possible for an expression to immediately follow [*] another expression with no intervening operator. The only case in which that can occur is where a semicolon is automatically inserted between the two expressions. Assume that case: then the second expression cannot begin with [*] a token whose first character is '/', because that would have been interpreted as a DivisionPunctuator, and so no semicolon insertion would have occurred (because semicolon insertion only occurs where there would otherwise have been a syntax error); contradiction. [*] Ignoring comments and whitespace. > however, since the lexical grammar uses the InputElementDiv goal symbol > in such cases, the opening slash is not recognised as starting a regular > expression literal in such a context. As a workaround, one may enclose > the regular expression literal in parentheses. > > ASI strikes again: > > a = b > /hi/g.exec(c).map(d); Semicolon insertion is not possible after 'b', because the '/' following it is a valid token in that context, so there is no syntax error that could prompt semicolon insertion. > The Note takes care of this. This is not a case where the note applies; it's essentially the same case as given by Eric Suen. My response to him is at <http://www.mail-archive.com/[email protected]/msg01331.html>. -- David-Sarah Hopwood ⚥ _______________________________________________ Es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
