英文:
range over an []interfaces{} and get the channel field of each type
问题
我会尽量清晰地解释一下，首先在我的脑海中。
我有一个接口和一些通过声明方法来继承它的类型。这是一种非常好的和聪明的继承方式。
然后我有一个"超级"类型Thing，所有其他类型都嵌入其中。
Thing结构体有一个Size int和一个Out chan属性。
我试图理解的是为什么我可以从子结构体中获取size的值.GetSize()，但是我在通道字段.GetChannel()上却没有同样的成功（我在其中使用通信来在goroutine和它们的调用者之间进行通信）。
...在这里我得到了t.GetChannel undefined (type Measurable has no field or method GetChannel)。
这里可能需要一个逻辑的演示：
package main
import (
"fmt"
)
type Measurable interface {
GetSize() int
}
type Thing struct {
Size int
Out chan int
}
type Something struct{ *Thing }
type Otherthing struct{ *Thing }
func newThing(size int) *Thing {
return &Thing{
Size: size,
Out: make(chan int),
}
}
func NewSomething(size int) *Something { return &Something{Thing: newThing(size)} }
func NewOtherthing(size int) *Otherthing { return &Otherthing{Thing: newThing(size)} }
func (s *Thing) GetSize() int { return s.Size }
func (s *Thing) GetChannel() chan int { return s.Out }
func main() {
things := []Measurable{}
pen := NewSomething(7)
paper := NewOtherthing(5)
things = append(things, pen, paper)
for _, t := range things {
fmt.Printf("%T %d \n", t, t.GetSize())
}
for _, t := range things {
fmt.Printf("%+v \n", t.GetChannel())
}
// for _, t := range things {
// fmt.Printf("%+v", t.Thing.Size)
// }
}
被注释的代码是我正在尝试学习的另一件事。我可以通过在超级类型上声明的方法来获取一个值，但是不能直接从子类型中访问。当然，我可以使用t.(*bothTheThingTypes).Size来解析类型，但我失去了动态性，我还没有完全理解这一点...
英文:
I'll try to make it as clear as possible, in my head first.
I have an interface and a couple of Types that inherit it by declaring a method. Pretty nice and clever way of inheritance.
I have then a "super" Type Thing, which all the other Types embed.
The Thing struct has a Size int and an Out chan properties
What I'm trying to understand is why I can get the value of size .GetSize() from both the child structs, but I don't have the same success with the channel field .GetChannel() (*ndr which I'm using to communicate among goroutines and their caller)
...here I get t.GetChannel undefined (type Measurable has no field or method GetChannel)
It might help a demo of the logic:
package main
import (
"fmt"
)
type Measurable interface {
GetSize() int
}
type Thing struct {
Size int
Out chan int
}
type Something struct{ *Thing }
type Otherthing struct{ *Thing }
func newThing(size int) *Thing {
return &Thing{
Size: size,
Out: make(chan int),
}
}
func NewSomething(size int) *Something { return &Something{Thing: newThing(size)} }
func NewOtherthing(size int) *Otherthing { return &Otherthing{Thing: newThing(size)} }
func (s *Thing) GetSize() int { return s.Size }
func (s *Thing) GetChannel() chan int { return s.Out }
func main() {
things := []Measurable{}
pen := NewSomething(7)
paper := NewOtherthing(5)
things = append(things, pen, paper)
for _, t := range things {
fmt.Printf("%T %d \n", t, t.GetSize())
}
for _, t := range things {
fmt.Printf("%+v \n", t.GetChannel())
}
// for _, t := range things {
// fmt.Printf("%+v", t.Thing.Size)
// }
}
The commented code is another thing I'm trying to learn. I can get a value by using a method declared on the super Type, but not by accessing directly from the child one. Sure, I could resolve the type with t.(*bothTheThingTypes).Size but I lose the dinamicity, I'm not fully getting this...
答案1
得分: 2
我正在尝试理解的是为什么我可以从两个子结构体中获取 GetSize() 方法的值，但是对于 GetChannel() 方法，我没有同样的成功。
type Measurable interface {
GetSize() int
}
...
things := []Measurable{}
for _, t := range things {
fmt.Printf("%+v \n", t.GetChannel())
}
我可能误解了问题，但这似乎严格是由于你的 Measurable 接口没有一个 GetChannel 方法引起的。
英文:
> What I'm trying to understand is why I can get the value of size
> .GetSize() from both the child structs, but I don't have the same
> success with the channel field .GetChannel()
type Measurable interface {
GetSize() int
}
...
things := []Measurable{}
for _, t := range things {
fmt.Printf("%+v \n", t.GetChannel())
}
I may be missing the point but this seems to be caused strictly by the fact that your Measurable interface doesn't have a GetChannel method.
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