"where both a division and a RegularExpressionLiteral are permitted"
eric.suen.tech at gmail.com
Sat Nov 29 18:53:03 PST 2008
a = a
this will cause syntax error instead of
a = a;
----- Original Message -----
From: "David-Sarah Hopwood"
<david.hopwood-mRVxzIiVagSlV3Ge8JjJtnfLna9zW77MtUK59QYPAWc at public.gmane.org>
To: <es-discuss-4eJtQOnFJqFAfugRpC6u6w at public.gmane.org>
Sent: Sunday, November 30, 2008 9:41 AM
Subject: "where both a division and a RegularExpressionLiteral are permitted"
> Section 7 (Lexical Conventions):
> # Note that contexts exist in the syntactic grammar where both a division
> # and a RegularExpressionLiteral are permitted by the syntactic grammar;
> # [...]
> I believe this statement is incorrect [*1].
> If I'm wrong, what is an example of such a context?
> [*1] A DivisionPunctuator must be preceded by an expression.
> A RegularExpressionLiteral is itself an expression.
> 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 [*2] 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 [*2] 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.
> [*2] Ignoring comments and whitespace.
> David-Sarah Hopwood
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