英文:
anonymous nested struct usage
问题
我之前问过这个问题并删除了它,但我还是不明白。我尝试了一切但仍然出错。我该如何使用这个结构体,或者我做错了什么?
type Unit struct{
category struct{
name string
}
}
英文:
I've asked this question before and deleted it. but I don't understand. I tried everything but still getting error. how can i use this struct. or am i doing it wrong
type Unit struct{
category struct{
name string
}
}
答案1
得分: 3
执行以下操作:
var unit = Unit{
category: {
name: "foo",
},
}
不起作用,因为语言规范规定,在使用复合字面值初始化结构的字段时,必须指定类型。例如,嵌套结构、映射或切片等。
由于category
的类型是一个未命名的复合类型,为了初始化该字段,必须重复未命名复合类型的定义。
type Unit struct{
category struct{
name string
}
}
var unit = Unit{
category: struct{
name string
}{
name: "foo",
},
}
或者,不要使用匿名结构。
type Category struct {
name string
}
type Unit struct{
category Category
}
var unit = Unit{
category: Category{
name: "foo",
},
}
如果你想在声明该结构的包之外使用该结构,你必须导出其字段。
type Category struct {
Name string
}
type Unit struct{
Category Category
}
// ...
var unit = mypkg.Unit{
Category: mypkg.Category{
Name: "foo",
},
}
英文:
Doing the following:
var unit = Unit{
category: {
name: "foo",
},
}
will NOT work because the language specification says that you MUST specify the type when initializing a struct's field with a composite literal value. E.g. a nested struct, or a map, or a slice, etc.
Since category
's type is an unnamed composite type, to initialize the field you MUST repeat the unnamed composite type's definition.
type Unit struct{
category struct{
name string
}
}
var unit = Unit{
category: struct{
name string
}{
name: "foo",
},
}
Alternative, do not use anonymous structs.
type Category struct {
name string
}
type Unit struct{
category Category
}
var unit = Unit{
category: Category{
name: "foo",
},
}
And if you want to use this struct outside of the package in which it is declared you MUST export its fields
type Category struct {
Name string
}
type Unit struct{
Category Category
}
// ...
var unit = mypkg.Unit{
Category: mypkg.Category{
Name: "foo",
},
}
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