GO：为什么不能++i,--i

《The Go Programming Language》中是这样写的:

---

The increment statement i++ adds 1 to i ; It’s equivalent to i+=1 which is in turn equivalent to i = i +1. There’s a corresponding decrement statement i– that subtracts 1. There are statements, not expressions as they are in mot languages in the C family,so j=i++ is illegal, and they are postfix only,so –i is not legal either.

---

增量声明i++让i加上1，这与i+=1、i=i+1是等效的。也有一个相应的递减式声明i–让i自减1。但在这里它们是声明式，而不是像C语言体系中的表达式，所以j=i++这种声明也是不合法的。并且它们只是个后缀（声明），所以–i同样也是不合法的表达。