> I agree completely (see also my other email): > - Never use objects as maps. > - Introduce collection classes. > - Try to make arrays fit into the collection framework. > > Great! But could you please post a pointer to that other email, or post a > summary? Thanks.
This is the original thread: http://www.mail-archive.com/es-discuss@mozilla.org/msg10464.html My understanding (using Allen’s terminology) is as follows (consult Allen’s email that started the thread for further details and a longer rationale). We have to separate the data domain from the program domain: - Arrays: [] is used to access both collection/array elements (data domain) and properties (program domain). - Objects: [] is used mainly for properties, but also for collection element access when (ab)using objects as maps from strings to values. Solutions: 1. New operator for the data domain: Introduce a new, separate operator .[] for accessing collection elements. Use it for all new collection types, implement it for arrays, too. 2. Rededicate [] to be used for the data domain only: Default behavior remains as is, but can be overridden in collection classes (including arrays). Using [] for property access is deprecated, you must use methods such as Object.setOwnProperty() and Object.getProperty() to do so. Addendum: edited quote from a recent email of mine: > I think it’s better to rededicate [] to be a collection element accessor: > - Introducing .[] would deprecate all existing array code and code that uses > objects as maps. > - Rededicating [] would only deprecate code that uses computed property names. > > It might make sense to have a "stricter mode" that turns off the default > behavior of []: > - It would thus force you to use methods such as (the yet to be defined) > Object.setOwnProperty() and Object.getProperty() when you want to compute the > name of a property. > - Stricter mode could also restrict [] for arrays to just numbers, including > negative numbers for accessing elements relative to the end of an array. -- Dr. Axel Rauschmayer a...@rauschma.de home: rauschma.de twitter: twitter.com/rauschma blog: 2ality.com
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