斯卡拉 - 柯里和默认参数

问题描述

我有，我想申请部分与柯里用两个参数列表的功能。第二个参数列表包含参数，所有有默认值（但不是隐含的）。事情是这样的：

I have a function with two parameter lists that I am trying to partially apply and use with currying. The second parameter list contains arguments that all have default values (but not implicit). Something like this:

 def test(a: Int)(b: Int = 2, c: Int = 3) { println(a + ", " + b + ", " + c); }

现在，以下是所有罚款：

Now, the following is all fine:

 test(1)(2, 3);
 test(1)(2);
 test(1)(c=3);
 test(1)();

现在，如果我定义：

 def partial = test(1) _;

那么下面可以做：

Then the following can be done:

 partial(2, 3);

有人能解释我为什么不能省略一些/部分所有参数如下：

Can someone explain why I can't omit some/all arguments in 'partial' as follows:

 partial(2);
 partial(c=3);
 partial();

不应该写部分的行为本质上是方式测试（1）一样吗？有人可以帮我想出一个办法来实现这一目标？

Shouldn't writing "partial" behave essentially the same way as "test(1)"? Can someone please help me figure out a way to achieve this?

请帮忙，我很绝望！

修改 - 既然不能在24小时内回答我的问题，我会在这里发表我自己的答案：

EDIT - Since I can't answer my own question within 24 hours, I'll post my own answer here:

这是我可以做自己，所以目前最好的：

This is the best I could do myself so far:

class Test2(val a: Int) {
   def apply(b: Int = 2, c: Int = 3) { println(a + ", " + b + ", " + c); }
}

def test2(a: Int) = new Test2(a);
def partial2 = test2(1); // Note no underscore

test2(1)(2, 3);
test2(1)(2);
test2(1)(c=3);
test2(1)();

partial2(2, 3)
partial2(2);
partial2(c=3);
partial2();

此方式，它的工作原理...

This way it works...

推荐答案

这是我可以做自己，所以目前最好的：

This is the best I could do myself so far:

class Test2(val a: Int) {
   def apply(b: Int = 2, c: Int = 3) { println(a + ", " + b + ", " + c); }
}

def test2(a: Int) = new Test2(a);
def partial2 = test2(1); // Note no underscore

test2(1)(2, 3);
test2(1)(2);
test2(1)(c=3);
test2(1)();

partial2(2, 3)
partial2(2);
partial2(c=3);
partial2();

此方式，它的工作原理...

This way it works...

这篇关于斯卡拉 - 柯里和默认参数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！