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golang的匿名struct
source link: https://studygolang.com/articles/25661
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go语言匿名struct的用例。
- 基本用例
package main import "fmt" func main() { v := struct { A int B string } { A: 10, B: "bb", } fmt.Printf("%+v\n", v) }
或者
package main import "fmt" func main() { v := struct { A int B string } { 10, "bb"} fmt.Printf("%+v\n", v) }
- 包含slice
package main import "fmt" func main() { v := struct { A int B string C []int } { 10, "bb", []int {1,2,3}} fmt.Printf("%+v\n", v) }
- 嵌套匿名struct
package main import "fmt" func main() { v := struct { A int B string C struct { C1 int C2 string } } { 10, "bb", struct {C1 int C2 string} { 100, "ccc"}, } fmt.Printf("%+v\n", v) }
这个地方需要注意的是在定义嵌套内对象的时候又有一遍类型的声明,感觉是重复的,显得代码不是很简洁,这没有办法go语言就这么设计的槽点,就像第二个例子的slice一样也是声明了两遍。
其实希望的这种语句格式:
1 package main 2 3 import "fmt" 4 5 func main() { 6 v := struct { 7 A int 8 B string 9 C struct { 10 C1 int 11 C2 string 12 } 13 } { 14 10, 15 "bb", 16 {100, "ccc"}, 17 } 18 19 fmt.Printf("%+v\n", v) 20 }
遗憾的是编译器不接受这种格式:
$ go build test.go # command-line-arguments ./test.go:16:9: missing type in composite literal
感觉编译器应该完全能支持这种格式,从语法分析上说,这种写法没有问题,而且不会产生二义,不知道golang出于什么原因不支持,很奇怪的说。
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