英文:
Writing a generic binder in Go
问题
考虑以下函数——第二个参数的绑定器。
func bindSecond(value interface{}, f func(a interface{}, b interface{})) func(c interface{}) {
return func(arg interface{}) {
f(arg, value)
}
}
考虑一个函数
func f(x int, y int) {}
当尝试将其作为绑定器的参数时，Go编译器报错：
cannot use f (type func(int, int)) as type func(interface {}, interface {}) in argument to bindSecond.
请问你能否为我提供在Go中实现绑定器的正确方法？
英文:
Consider the following function -- a binder of the second argument.
func bindSecond(value interface{}, f func(a interface{}, b interface{})) func (c interface{}) {
return func(arg interface{}) {
f(arg, value)
}
}
Consider a function
func f(x int, y int) {}
When trying to use it as a parameter in binder, go compiler says:
cannot use f (type func(int, int)) as type func(interface {}, interface {}) in argument to bindSecond.
Could you please suggest me the proper way of implementing binders in go (golang)?
答案1
得分: 4
将interface{}替换为int，它就会工作。
或者更重要的是，尝试使用Go提供的功能来找到解决方案，而不是试图从不同的范式中强行解决问题。
英文:
Replace interface{} with int and it will work.
Or, more to the point, try to find a solution to your original problem using the features Go provides, instead of trying to force a solution from a different paradigm.
答案2
得分: 4
我明白你想做什么，一些模板对吧？但是这种方式行不通。你的 f func(a interface{}, b interface{}) 参数不是一个接口，所以它必须是匹配的类型。你可以通过传递 f interface{} 并使用 reflect 包来实现你想要的效果。
这是一个简单的示例：
package main
import (
"fmt"
"reflect"
)
func bindSecond(value interface{}, f interface{}) func(c interface{}) {
return func(arg interface{}) {
reflect.ValueOf(f).Call([]reflect.Value{reflect.ValueOf(arg), reflect.ValueOf(value)})
}
}
func main() {
sum := func(x int, y int) { fmt.Println(x + y) }
inc := bindSecond(1, sum)
inc(10)
}
// 输出 11
这样是可行的，但不太美观。如果发生任何意外情况，例如 f 不可调用或不接受恰好两个参数，或者你向 inc 传递了错误的类型，它会在运行时引发 panic。编译器将无法再帮助你。
英文:
I see what you're trying to do, some templates, right? But this is not going to work this way. Your f func(a interface{}, b interface{}) argument is not an interface, so it must be of the matching type. You could achieve what you want by passing f interface{} and then manipulate it with reflect package.
Some naive example:
package main
import (
"fmt"
"reflect"
)
func bindSecond(value interface{}, f interface{}) func(c interface{}) {
return func(arg interface{}) {
reflect.ValueOf(f).Call([]reflect.Value{reflect.ValueOf(arg), reflect.ValueOf(value)})
}
}
func main() {
sum := func(x int, y int) { fmt.Println(x + y) }
inc := bindSecond(1, sum)
inc(10)
}
// Prints 11
Doable, but not very pretty. And panics in runtime if anything unexpected happens, for example f is not callable and doesn't take exactly two arguments. Or you pass a wrong type to inc. Complier won't help you anymore.
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