Object.is(0,-0) and its data structures implications

2012-12-03 Thread Olov Lassus
Hello, I've been thinking about our IEEE-inherited positive and negative zero and the proposed ES6 Object.is and new collections semantics. I haven't followed any discussions about this so I'm basing my understanding purely on the Harmony wiki and toying around with the preliminary support in

Re: Number.isNaN

2012-12-18 Thread Olov Lassus
2012/12/14 Allen Wirfs-Brock al...@wirfs-brock.com BTW, I think there are probably other related issues that need to be discussed/resolved at that level. For example, is SameValue really want we want for Map/Set equivalence (the -0 different from +0 issue), did we agree to parameterize the

Re: B.3.1 The __proto__ pseudo property

2013-04-21 Thread Olov Lassus
2013/4/21 Allen Wirfs-Brock al...@wirfs-brock.com Also note that JSON.parse('{__proto__: null}') does not create an object whose [[Protoype]] is null because JSON.parse uses [[DefineOwnProperty]] to create all its properties so this will just result in an own property whose value is null.

Re: proposal for efficient 64-bit arithmetic without value objects

2013-10-30 Thread Olov Lassus
2013/10/30 Vyacheslav Egorov m...@mrale.ph 5. A one shot property Math.H is created that returns ch' on the first access and deletes itself. Alternative step 5: Math.H is assigned ch'. Rationale being faster polyfilled execution, in combination with a lack of imagination from my side to come

Re: proposal for efficient 64-bit arithmetic without value objects

2013-10-30 Thread Olov Lassus
2013/10/30 Vyacheslav Egorov m...@mrale.ph Rationale being faster polyfilled execution The main reason for H being one shot is to allow optimizing compiler *elide* updating it in most cases to eliminate memory traffic. Aaah. Thanks for pointing this out - I thought only of the polyfill

Re: if-scoped let

2013-12-04 Thread Olov Lassus
2013/11/29 Nick Krempel ndkrem...@google.com Couldn't find anything on this in the archives, but is there a proposal for: if (let var = expr) { // var in scope } ... (const should also be OK in place of let, at least for if and switch.) Thanks for taking this to the list. I was

Re: Object.is()

2013-12-22 Thread Olov Lassus
2013/12/23 Brendan Eich bren...@mozilla.com You are reasoning from general to particular, but without any reason to focus on the particular of redefining a non-writable property from -0 to +0 or vice versa. There is no use-case there there! I bet Mark would find that a subtle security

Re: Object.is()

2013-12-22 Thread Olov Lassus
2013/12/23 Mark S. Miller erig...@google.com No, Map and Set will equate -0 and +0. \o/ Filed a bug on v8: https://code.google.com/p/v8/issues/detail?id=3069 ___ es-discuss mailing list es-discuss@mozilla.org