On Tue, Jan 22, 2019 at 7:59 PM <mountain...@gmail.com> wrote: > > When i use the func, map slice as the key of map, it isn't work! > So I lookup source why, i find
You don't have to look at the source, you can look at the language spec. https://golang.org/ref/spec#Map_types "The comparison operators == and != must be fully defined for operands of the key type; thus the key type must not be a function, map, or slice." In Go, function values are not comparable, so they can not be used as map keys. This is to avoid various sorts of confusion. For example, given this: func F() func() int { i := 0 return func() int { i++ return i } } should F() == F()? There is no obvious answer that clearly correct in all cases, so we don't permit comparing function values at all. Ian -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
