英文:
Export functions from internal package in Go
问题
我正在测试将大部分代码放在一个internal包中，然后选择性地将其中的方法/类型暴露给外部世界。代码看起来像这样：
/mypackage/internal/catapult
package catapult
func Load(boulder Boulder) {
// ...
}
func Trigger() *Launch {
// ...
}
// ...
也许Load被其他内部包（/mypackage/internal/randomevents/boredsoldier和/mypackage/internal/actualattackstrategy）调用，但不应该被internal以外的用户调用。所有这些包只允许在加载弹弓后触发它。
现在，我想在internal上面有一个包（/mypackage/general），其中Trigger被公开，但Load不被公开。我希望能做到这样：
package general
const TriggerCatapult = catapult.Trigger
// ^ 这样做不起作用，因为函数不能是常量
var TriggerCatapult = catapult.Trigger
// ^ 从技术上讲可以工作，但现在 TriggerCatapult 的值可以被任何包的用户覆盖
func TriggerCatapult() *catapult.Launch {
return catapult.Trigger()
}
// ^ 这样可以工作。只是每次都要重新编写整个函数的签名有点“痛苦”
有更好的方法吗？
英文:
I'm testing the idea of putting most of my code in an internal package and then picking exactly which of the methods / types from there I'm exposing to the outside world. Code would look like:
/mypackage/internal/catapult
package catapult
func Load(boulder Boulder) {
// ...
}
func Trigger() *Launch {
// ...
}
// ...
Maybe Load is being called by other internal packages (/mypackage/internal/randomevents/boredsoldier and /mypackage/internal/actualattackstrategy) but shouldn't be allowed by users outside of internal. All those are allowed to do is Trigger the catapult once it's loaded.
So now I'd like to have a package above internal (/mypackage/general) where Trigger is exposed but not Load. I was hoping to do something like:
package general
const TriggerCatapult = catapult.Trigger
// ^ does not work because a function cannot be a const
var TriggerCatapult = catapult.Trigger
// ^ technically works but now the value of TriggerCatapult can be overwritten by any package user
func TriggerCatapult() *catapult.Launch {
return catapult.Trigger()
}
// ^ works. It's just "painful" to have to reproduce the entire function's signature every time
Is there a better way to do this?
答案1
得分: 1
不，你提供的方式是没有更好的方法来做这个的：
func TriggerCatapult() *catapult.Launch {
return catapult.Trigger()
}
不过，你不应该返回未导出的类型，大多数代码检查工具会为你捕捉到这个问题。
如果用户要直接与catapult中的内容进行交互，那么该包就不应该是内部的。
英文:
No, there is no better way to do this that the way you provide:
func TriggerCatapult() *catapult.Launch {
return catapult.Trigger()
}
You shouldn't return unexported types though, and most linters would catch this for you.
If a user is going to interact directly with things in catapult, then that package should not be internal.
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