On Jun 21, 2011, at 12:50 AM, Luke Hoban wrote: > My read of the spec is that thi\u0073 is a ReservedWord and should not be > allowed as an Identifer. So the following part of the examples quoted below > should be an early error: > > var thi\u0073 = 42; > > The text in 7.6 seems to address this with: > > "All interpretations of identifiers within this specification are based upon > their actual characters regardless of whether or not an escape sequence was > used to contribute any particular characters." > > Luke
+1 I can't dig into the spec. right now but the section Luke quoted is the one I was going to try to dig for. Allen > > -----Original Message----- > From: es-discuss-boun...@mozilla.org [mailto:es-discuss-boun...@mozilla.org] > On Behalf Of Mike Samuel > Sent: Monday, June 20, 2011 2:18 PM > To: Oliver Hunt > Cc: es-discuss > Subject: Re: this vs thi\u0073 > > 2011/6/20 Oliver Hunt <oli...@apple.com>: >> Without looking at the spec but just based on what I know our lexer (JSC) >> does, we won't consider any identifier with escaped characters to be a >> keyword, so yes you could make identifiers that technically match language >> keywords, but you'd never be able to use them directly (without escaping). > > You can due to global object aliasing. > > var thi\u0073 = 42; > alert([this.this === 42, // Look ma, no escaping! > this["this"] === 42]); // Look ma, still no escaping! > > works in Firefox. > > The first is legal because MemberExpression is defined as > MemberExpression . IdentifierName > not > MemberExpression . Identifier > and it is only Identifier that is not allowed to be a reserved word > Identifier :: IdentifierName but not ReservedWord > IdentifierName :: IdentifierStart > | IdentifierName IdentifierPart > _______________________________________________ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/listinfo/es-discuss > > _______________________________________________ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/listinfo/es-discuss _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
