Idiom for exiting from for { select { ... } }?

[mcandre (Andrew Pennebaker)]

What is the right way to instruct Go to leave a for { select { ... } } block? I tried break, but unfortunately break only leaves the inner select block, I think as a historical fact that break is associated with terminating case blocks within switches

Should we declare a boolean variable and do for theVar { select { ... } }?

Use assembler labels?

Wrap in an anymous 0-ary function and immediately call it, with return keyword? Reeks of ECMAScript 3 nonsense…

[joncalhoun]

A boolean variable is one option. Another might be to move some of the code into a function that you can return from. A third option, which is likely what you are looking for, is a label and a break label. Basically this is what they look like:

func main() {

// This is the label
PrintLoop:
	for {
		select {
		case <-done:
                    // This is the break with a label
			break PrintLoop
		case word := <-word:
		}
	}
}

You can see this actually being used here: https://play.golang.org/p/sdq26w8btci

Note: The term “label” is used in effective Go and should be accurate, but I’m not 100% what to call a break statement with a label so I just go with “break label” or “labelled break”. If someone knows an official term please share it.

[johandalabacka (Johan Dahl)]

https://golang.org/test/label1.go calls it break label

[geosoft1 (George Calianu)]

Well, the labels must be used very carefuly and are very limited situations where a label is needed. Is better to use any other standard methods instead because jumping uncontrolled in your application can have unexpected results.