不同 sbt Key 操作符的用例 [英] Use cases for different sbt Key operators

问题描述

这里似乎真的缺少 sbt 的文档，所以我想得到一个明确的答案:+="、++="、<+="、<++=", 和 "<<=" 在 Keys 上操作时?

The documentation for sbt seems to be really lacking here, so I'd like to get a definitive answer on this: what is the difference between "+=", "++=", "<+=", "<++=", and "<<=" when operating on Keys?

推荐答案

您找不到文档，因为@JacekLaskowski 正确指出了除 +=、++=<之外的所有运算符/code> 和 := 已弃用.

You cannot find documentation, because as @JacekLaskowski correctly pointed out all operators except for +=, ++= and := are deprecated.

但是，您可以找到 Documentation 如果你切换到旧版本的 sbt.

You can however find the Documentation if you switch to older version of sbt.

但是，如果您坚持使用旧版本，这就是它们的含义(通过文档):

If you however are stuck to older version, this is their meaning (via documentation):

• += 和 ++= 追加到前一个值，其中首先追加单个元素，然后追加Seq
• ~= 转换值，例如您想使用存储在设置中的值来获取新设置.
• <<= 依赖另一个键，例如如果你调用 organization <<= name，那么 organization 值等于 name 值.您可以依赖多个值，例如组织 <<= (name, version) { (n, v) =>/* 对值做一些事情 */}
• <+= 和 <++= 是 附加依赖项，与附加类似，但您可以使用其他设置值来计算新值

• += and ++= append to previous value, where first appends single element and next appends a Seq
• ~= transforms value, e.g. you want to use value stored in a setting to get a new setting.
• <<= depends on another key, for example if you call organization <<= name, then organization value is equal to name value. You can depend on multiple values, e.g. organization <<= (name, version) { (n, v) => /* do something with values */ }
• <+= and <++= are appending with dependencies, like the append, but you can use another's setting value to compute new value

也就是说，@JacekLaskowski 是对的，如果您使用的是 sbt 13.x 或更高版本，则不必使用这些运算符来支持宏.

Said that, @JacekLaskowski is right, and if you are using sbt 13.x or greater you should not have to use those operators in favours of macros.

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