将函数的值作为输入参数返回给另一个 [英] Return values of function as input arguments to another

问题描述

如果我有

func returnIntAndString() (i int, s string) {...}

我有:

func doSomething(i int, s string) {...}

然后我可以成功完成以下操作:

Then I can do the following successfully:

doSomething(returnIntAndString())

但是，假设我要向doSomething添加另一个参数，例如:

However, let's say I want to add another argument to doSomething like:

func doSomething(msg string, i int, s string) {...}

如果我这样称呼，Go在编译时会抱怨:

Go complains when compiling if I call it like:

doSomething("message", returnIntAndString())

使用:

main.go:45: multiple-value returnIntAndString() in single-value context
main.go:45: not enough arguments in call to doSomething()

有没有办法做到这一点，还是我应该放弃并将returnIntAndString的返回值分配给某些引用，并传递msg和这些值，例如doSomething(msg, code, str)?

Is there a way to do this or should I just give up and assign the return values from returnIntAndString to some references and pass msg and these values like doSomething(msg, code, str) ?

推荐答案

在规范中中进行了描述.它要求内部函数返回所有参数的正确类型.没有多余的参数以及返回多个值的函数.

It's described here in the spec. It requires the inner function to return the correct types for all arguments. There is no allowance for extra parameters along with a function that returns multiple values.

在特殊情况下，如果函数或方法g的返回值为 数量相等，可分别分配给以下参数 另一个函数或方法f，则调用f(g(parameters_of_g))将 将g的返回值绑定到f的参数后调用f 为了. f的调用除调用外不得包含任何参数 g的值，并且g必须至少具有一个返回值.如果f具有最终值... 参数，分配给g的返回值保留在 常规参数的分配.

As a special case, if the return values of a function or method g are equal in number and individually assignable to the parameters of another function or method f, then the call f(g(parameters_of_g)) will invoke f after binding the return values of g to the parameters of f in order. The call of f must contain no parameters other than the call of g, and g must have at least one return value. If f has a final ... parameter, it is assigned the return values of g that remain after assignment of regular parameters.

func Split(s string, pos int) (string, string) {
  return s[0:pos], s[pos:]
}

func Join(s, t string) string {
  return s + t
}

if Join(Split(value, len(value)/2)) != value {
  log.Panic("test fails")
}

如果不满足这些特定条件，则需要分配返回值并分别调用该函数.

If those specific conditions are not met, then you need to assign the return values and call the function separately.

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