select - break 语句是否从 switch/select 中断？

Question

我知道 switch/select 语句在每个 case 之后都会自动中断。我想知道，在以下代码中:

for {
    switch sometest() {
    case 0:
        dosomething()
    case 1:
        break
    default:
        dosomethingelse()
    }
}

break 语句是退出 for 循环还是仅退出 switch block ？

Answer 1

Break statements, The Go Programming Language Specification.

A "break" statement terminates execution of the innermost "for", "switch" or "select" statement.

BreakStmt = "break" [ Label ] .

If there is a label, it must be that of an enclosing "for", "switch" or "select" statement, and that is the one whose execution terminates (§For statements, §Switch statements, §Select statements).

L:
  for i < n {
      switch i {
      case 5:
          break L
      }
  }

因此，您示例中的 break 语句终止了 switch 语句，即“最内层”语句。