我有以下代码:
type FWriter struct { WriteF func(p []byte) (n int,err error) } func (self *FWriter) Write(p []byte) (n int, err error) { return self.WriteF(p) } func MyWriteFunction(p []byte) (n int, err error) { // this function implements the Writer interface but is not named "Write" fmt.Print("%v",p) return len(p),nil } MyFWriter := new(FWriter) MyFWriter.WriteF = MyWriteFunction // I want to use MyWriteFunction with io.Copy io.Copy(MyFWriter,os.Stdin)
我想做的是创建一个Writer接口来包装,MyWriteFunction因为它没有命名为“ Write”,并且我不能将其与任何需要“ Writer”接口的东西一起使用。
MyWriteFunction
该代码无法正常工作,因为它抱怨:
方法MyWriterFunction不是表达式,必须调用
我在这里做错了什么?如何设置WriteF是MyWriteFunction?
WriteF
注意:我尽了最大的努力简化了这个问题,实际上我有一个具有MyWriteFunctionAND普通Write函数的结构,所以它有点复杂…(如果还有更好的方法可以解决我的问题,我很高兴听到它!)
谢谢!!
编辑: 我注意到我的错字并修正了(MyWriterFunction-> MyWriteFunction)。
MyWriterFunction
我认为我过分简化了问题,以致使您误解了我的初衷。在匿名评论和peterSO类评论之后,我重新创建了错误以更好地演示我的问题:
package main import ( "fmt" "io" "strings" ) type ProxyWrite interface { Write(p []byte) (n int, err error) SpecialWrite(p []byte) (n int, err error) } type Implementer struct { counter int } func (self Implementer) Write(p []byte) (n int, err error) { fmt.Print("Normal write: %v", p) return len(p),nil } func (self Implementer) SpecialWrite(p []byte) (n int, err error) { fmt.Print("Normal write: %v\n", p) fmt.Println("And something else") self.counter += 1 return len(p),nil } type WriteFunc func(p []byte) (n int, err error) func (wf WriteFunc) Write(p []byte) (n int, err error) { return wf(p) } func main() { Proxies := make(map[int]ProxyWrite,2) Proxies[1] = new(Implementer) Proxies[2] = new(Implementer) /* runs and uses the Write method normally */ io.Copy(Proxies[1], strings.NewReader("Hello world")) /* gets ./main.go:45: method Proxies[1].SpecialWrite is not an expression, must be called */ io.Copy(WriteFunc(Proxies[1].SpecialWrite), strings.NewReader("Hello world")) }
我希望它能澄清我在第一次尝试中要表达的意思。
有什么想法吗?
您的代码中有错别字,但是无论如何都不需要将函数包装到结构中。相反,您可以只定义一个包装函数的WriteFunc类型,并可以在其上定义Write方法。这是一个完整的例子。
package main import ( "fmt" "io" "strings" ) type WriteFunc func(p []byte) (n int, err error) func (wf WriteFunc) Write(p []byte) (n int, err error) { return wf(p) } func myWrite(p []byte) (n int, err error) { fmt.Print("%v", p) return len(p), nil } func main() { io.Copy(WriteFunc(myWrite), strings.NewReader("Hello world")) }