The Go Programming Language

12.5 Setting Variables with reflect.Value

So far, reflection has only interpreted values in our program in various ways. The point of this section, however, is to change them.

Recall that some Go expressions like x, x.f[1], and *p denote variables, but others like x + 1 and f(2) do not. A variable is an addressable storage location that contains a value, and its value may be updated through that address.

A similar distinction applies to reflect.Values. Some are addressable; others are not. Consider the following declarations:

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x := 2                     // value   type   variable?
a := reflect.ValueOf(2)    // 2       int    no
b := reflect.ValueOf(x)    // 2       int    no
c := reflect.ValueOf(&x)   // &x      *int   no
d := c.Elem()              // 2       int    yes (x)

The value ...