Add the method to the interface constraint, without forgoing generics: type AB interface { *A | *B some() bool } func some[T AB](x T) bool { return x.some() // works } This restricts T to types that are either *A or *B and declare some() bool method. However, as you already found out, this is … Read more
The solution here seems to be that the library I’m trying to use needs to be reworked to prevent this kind of thing from happening. The two possible ways to change the library seem to be 1) not vendor at all – this works if the dependency does not need to be a specific version. … Read more
Yes, it’s possible. You have 2 (3) options: Spec: Method expressions The expression Foo.A yields a function equivalent to A but with an explicit receiver as its first argument; it has signature func(f Foo). var foo Foo bar := func(m func(f Foo)) { m(foo) } bar(Foo.A) bar(Foo.B) bar(Foo.C) Here the method receiver is explicit. You … Read more
That seems coherent (see also “Defer, Panic, and Recover“) Deferred function calls are executed in Last In First Out order after the surrounding function returns. This function prints “3210”: func b() { for i := 0; i < 4; i++ { defer fmt.Print(i) } } The last call when the defer is evaluated means i=3, … Read more
I agree you should use the fmt.Fprint functions if you can manage it. However, if you don’t control the code whose output you’re capturing, you may not have that option. Mostafa’s answer works, but if you want to do it without a temporary file you can use os.Pipe. Here’s an example that’s equivalent to Mostafa’s … Read more
The Go blog: Go maps in action has an excellent explanation. When iterating over a map with a range loop, the iteration order is not specified and is not guaranteed to be the same from one iteration to the next. Since Go 1 the runtime randomizes map iteration order, as programmers relied on the stable … Read more
You can use sync.WaitGroup. Quoting the linked example: package main import ( “net/http” “sync” ) func main() { var wg sync.WaitGroup var urls = []string{ “http://www.golang.org/”, “http://www.google.com/”, “http://www.somestupidname.com/”, } for _, url := range urls { // Increment the WaitGroup counter. wg.Add(1) // Launch a goroutine to fetch the URL. go func(url string) { // … Read more
There isn’t a more concise way, what you did is the “right” way; because slices are always one-dimensional but may be composed to construct higher-dimensional objects. See this question for more details: Go: How is two dimensional array’s memory representation. One thing you can simplify on it is to use the for range construct: a … Read more
You can use reflect.DeepEqual, or you can implement your own function (which performance wise would be better than using reflection): http://play.golang.org/p/CPdfsYGNy_ m1 := map[string]int{ “a”:1, “b”:2, } m2 := map[string]int{ “a”:1, “b”:2, } fmt.Println(reflect.DeepEqual(m1, m2))
No, Go does not provide a REPL(read–eval–print loop). However, as already mentioned, Go Playground (this is the new URL) is very handy. The Go Authors are also thinking about adding a feature-rich editor to it. If you want something local, consider installing hsandbox. Running it simply with hsandbox go will split your terminal screen (with … Read more