在Golang类型断言中可以使用反射数组类型吗？

Question

I need to check if interface{} is an array and create corresponding slice if it is. Unfortunately I do not know array length in advance.

For example:

import (
  "reflect"
)
func AnythingToSlice(a interface{}) []interface{} {
  rt := reflect.TypeOf(a)
  switch rt.Kind() {
  case reflect.Slice:
    slice, ok := a.([]interface{})
    if ok {
      return slice
    }
    // it works

  case reflect.Array:
    // return a[:]
    // it doesn't work: cannot slice a (type interface {})   
    //
    array, ok := a.([reflect.ValueOf(a).Len()]interface{})
    // :-((( non-constant array bound reflect.ValueOf(a).Len()
    if ok {
       return array[:]
    }

  }
  return []interface{}(a)
}

Answer 1

An explicit type is required in a type assertion. The type cannot be constructed through reflection.

Unless the argument is a []interface{}, the slice or array must be copied to produce a []interface{}.

Try this:

func AnythingToSlice(a interface{}) []interface{} {
    v := reflect.ValueOf(a)
    switch v.Kind() {
    case reflect.Slice, reflect.Array:
        result := make([]interface{}, v.Len())
        for i := 0; i < v.Len(); i++ {
            result[i] = v.Index(i).Interface()
        }
        return result
    default:
        panic("not supported")
    }
}

https://play.golang.org/p/3bXxnHOK8_