As before with the hash index, you need to define a key generator UDF, a range producer UDF, the index extension, and finally a UDF that exploits the index extension if possible.

与hash索引一样，这里需要定义一个键生成器udf、一个范围生成器udf、一个索引扩展以及一个利用索引扩展的UDF。

youdao

This means pretty much any feature you'd like on a cellphone is possible on Android—even the officially unsupported multitouch interaction—provided someone can write an app or extension for it.

这意味着任何手机特性在Android上都有可能得到第三方实现——甚至是官方不支持的多点触摸。

youdao

While UTF-8 is the recommended encoding, others are possible which keeps XML from being tied to any particular encoding and provides a clear extension point for the future.

虽然推荐使用 UTF-8 编码，但也允许其他编码格式，这样 XML 就不会与特定编码捆绑在一起，这为将来提供了明确的扩展点。

youdao

"In recent years, the development of rapid, diagnostic tests for malaria, also known as RDTs, which can be performed by healthcare workers after a brief training has made the extension of diagnostic testing to rural health facilities possible."

VOA: standard.2010.03.09

The seven-mile (11km) route would have gone from Mickleover and Mackworth to Pride Park, with a possible extension to the High Speed 2 rail hub at Toton.

BBC: Nottingham tram

Any decision about the painting's current export will now be deferred until 7 April 2013, with a possible extension to 7 August if a serious intention to purchase the painting is found.

BBC: Rare Cropsey landscape in export bar

The mission, which Syria's government has said would be given one month to complete its work, with a month's extension possible, will release a report on its findings by week's end.

WSJ: Arab World Diplomacy Fails to Stop Syria Clash