By the way, this is covered by in Donovan & Kernighan's new book The Go Programming Language. On pages 197 and 198 of the first edition, they describe an interface Expr, representing an expression, then five concrete types that satisfy that interface and contain different sorts of expressions and sub expressions. Since they all implement the Expr type, you can write a method that can receive and return any or all of them.
However, there are some subtleties which can trip you up. Once you start using interfaces rather than concrete types, you are pretty quickly forced into using pointers rather than objects. Go does a pretty good job of hiding some of the details of this, but not a complete job. Interfaces are also crucial to a lot of testing strategies, because using them allows you to easily mock up objects with the values that you need for your tests. Unfortunately, this means that somebody new to Go has to get their head around quite a few tricky ideas before they can do anything useful. They are all explained in the book, but you need to read the relevant sections carefully, do a few experiments and then read them again and again until it becomes clear. The great thing about Kernighan's writing style is that he says everything he needs to say exactly once and using the minimum of words. The thing that often causes his readers problems is that he says everything he needs to say exactly once and using the minimum of words. -- 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.
