Why is XML store not available in iOS?

From the Core Data Prog开发者_StackOverflowramming Guide:

iOS: The XML store is not available on iOS.

Why isn't this available? Is it because of the lack of certain XML classes or does it require too much processing power or RAM?

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Apple would be the authoritative source for this, so we can only guess.

It’s probably because of two factors: XML stores are slower (as stated in the official documentation, mainly because of the need to parse XML and lack of efficient algorithm/data structures for common database operations) and potentially use more disk space than SQLite stores (since data must be enclosed in tags and XML stores use human-readable representation of data).

Edit: libxml2 is available on iOS so XML parsing functionality (or lack thereof) is certainly not the reason.