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User:Waldo/Internationalization API: Difference between revisions
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User:Waldo/Internationalization API (view source)
Revision as of 01:12, 11 February 2014
, 11 February 2014more tweaking
(Update for lazy Intl object initialization work) |
(more tweaking) |
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Internals objects are objects with null <code><nowiki>[[Prototype]]</nowiki></code> and the properties <code>type</code>, <code>lazyData</code>, and <code>internalProps</code>. This structure permits internals objects to be ''lazily'' initialized. Initially, <code>type</code> is <code>"partial"</code>; lazy initialization changes this to <code>"Collator"</code>, <code>"DateTimeFormat"</code>, or <code>"NumberFormat"</code> and sets <code>lazyData</code> to the information necessary to compute full initialization info; finally, first use fully initializes, converting <code>lazyData</code> into an <code>internalProps</code> object containing the actual ECMA-402-defined internal properties. (For more details on this scheme, see <code>initializeIntlObject</code> and adjacent functions, as well as the class-specific initialization methods, in {{source|js/src/builtin/Intl.js}}.) | Internals objects are objects with null <code><nowiki>[[Prototype]]</nowiki></code> and the properties <code>type</code>, <code>lazyData</code>, and <code>internalProps</code>. This structure permits internals objects to be ''lazily'' initialized. Initially, <code>type</code> is <code>"partial"</code>; lazy initialization changes this to <code>"Collator"</code>, <code>"DateTimeFormat"</code>, or <code>"NumberFormat"</code> and sets <code>lazyData</code> to the information necessary to compute full initialization info; finally, first use fully initializes, converting <code>lazyData</code> into an <code>internalProps</code> object containing the actual ECMA-402-defined internal properties. (For more details on this scheme, see <code>initializeIntlObject</code> and adjacent functions, as well as the class-specific initialization methods, in {{source|js/src/builtin/Intl.js}}.) | ||
The <code>internalProps</code> object stores the internal properties (other than <code><nowiki>[[initializedIntlObject]]</nowiki></code>) of the object, named naturally — "calendar", "initializedDateTimeFormat", and so on (no brackets). Accessing any internal property is simply a matter of doing <code>internals.calendar</code>: this is safe because, with the <code><nowiki>[[Prototype]]</nowiki></code> nulled out, property accesses can't touch any script-visible state. These internal properties are lazily computed to construct an ICU structure when collation/formatting/etc. actually occurs in the <code>js::intl_CompareStrings</code>, <code>js::intl_FormatNumber</code>, and <code>js::intl_FormatDateTime</code> functions. (Although not ''directly'' there, but rather in sub-methods called when the ICU structure isn't cached, or when the object was initialized as an <code>Intl</code> object but wasn't actually one — see again the "inefficiently" bit above.) | |||
=== Care and feeding of the Internationalization API === | === Care and feeding of the Internationalization API === | ||