CODEWITHSUNDEEP
goreflection
Antony360
Antony360

Reputation: 1

How to cast a reflect.Value by its type when created by reflect.New

I'm actually trying some black magic using reflection in golang :P

I got something like this :

  var _int int
  var _int32 int32
  var _int64 int64
  var _string string

    var nilablesIndex map[int]reflect.Value
    var nilables = map[string]reflect.Type {
           "int32":     reflect.TypeOf(_int32)},
           "int64":     reflect.TypeOf(_int64)},
           "int":       reflect.TypeOf(_int)},
           "string":    reflect.TypeOf(_string)},
        }
nilablesIndex[len(m) - 1] = reflect.New(nilables[field.Type.String()][1])

To summarize, I have at this moment a reflect.Value created by reflect.New(nilables[field.Type.String()][1])

That I want is to cast this variable by its original type.

Example : If nilablesIndex[0] is a reflect.Type int32, I want to cast it to type int32.

Is it possible ?

Thank you :)

Upvotes: 0

Views: 5623

Answers (1)

icza
icza

Reputation: 417462

You can't make it dynamic, because you are actually converting to a concrete type (what would be the type of the result if it would be dynamic? interface{}? you'd be back at the start).

You may use Value.Interface() and a type assertion.

For example:

var i int32 = 3

v := reflect.ValueOf(i)

x := v.Interface().(int32)
fmt.Printf("%T %v", x, x)

Output (try it on the Go Playground):

int32 3

Upvotes: 1

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