On Monday, October 2, 2017 at 11:10:58 PM UTC-7, Christian Surlykke wrote: > > Den mandag den 2. oktober 2017 kl. 21.33.04 UTC+2 skrev Dave Cheney: >> >> Back before aliases defined types used to be called named types, which >> permitted the existence of unnamed types. >> >> map[string]string >> >> is an unnamed type >> >> type Dictionary map[string]string >> >> is a named type, its name is Dictionary >> >> And the rules of assignment permitted assignment from or to an unnamed >> type. >> >> > Aha, I see. Thanks for clarifying. > > br. Chr. > > >> On Tuesday, 3 October 2017 06:26:44 UTC+11, Christian Surlykke wrote: >>> >>> Forgive me if this has been asked before. I've not been able to find a >>> diskussion about it. >>> >>> A snippet like this >>> >>> type AppleCount uint32 >>> >>> var i uint32 = 7 >>> >>> Isn't uint32 an unnamed type?
> var ac AppleCount = i >>> >>> why did this fail? > >>> will fail to compile with an error like: >>> >>> cannot use i (type uint32) as type AppleCount in assignment >>> >>> >>> OTOH code like this: >>> >>> type Dictionary map[string]string >>> var m map[string]string = make(map[string]string) >>> var d Dictionary = m >>> >>> >>> compiles just fine. >>> >>> There is this about type definitions in The Go Programming Language >>> Specification: >>> >>> *A type definition creates a new, distinct type with the same underlying >>> type and operations as the given type, and binds an identifier to it.* >>> >>> TypeDef = identifier Type . >>> >>> *The new type is called a defined type. It is different from any other >>> type, including the type it is created from.* >>> >>> >>> which I would take to mean that the second snippet should be invalid. >>> >>> Is this a bug or 'working as intended'? If it's working as intended, can >>> anyone explain the reasoning behind this? >>> >>> br. Christian Surlykke >>> >> -- 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.
