# Instantiate enum from String
**URL:** https://softwaremill.community/t/instantiate-enum-from-string/111
**Category:** magnolia
**Created:** [February 3, 2023, 10:37am UTC](https://softwaremill.community/t/instantiate-enum-from-string/111 "2023-02-03T10:37:21Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@sake92](https://softwaremill.community/u/sake92)
#### Post date: [February 3, 2023, 10:37am UTC](https://softwaremill.community/t/instantiate-enum-from-string/111/1 "2023-02-03T10:37:21Z")
I have a simple use case, parsing JSON.
This is my typeclass, simplified:
```plaintext
trait JsonReader[T]:
def parse(jValue: String): T
```
So basically I want to convert a String to a simple enum:
```plaintext
enum Color:
case Red, Blue
```
I want to parse string “Red” to Color.Red enum.
The only thing I found that is close is `ctx.choose(v)`, but that works on `T` values, and I only have a String…
Another thing that comes to my mind is using runtime reflection (for which I don’t have a working example).
But it would make sense to me that we can do this at compile time.
Is there an easy way I can do this with magnolia?
---
### Author:  [@adamw](https://softwaremill.community/u/adamw)
#### Post date: [February 3, 2023, 3:36pm UTC](https://softwaremill.community/t/instantiate-enum-from-string/111/2 "2023-02-03T15:36:04Z")
If you have access to the `SealedTrait` instance, you can get the subtypes via `.subtypesArray`, and then access the `.typeName` to find the appropriate subtype. From that, you can get the typeclass instance for the subtype.
You can then call `.parse` on that typeclass instance - which corresponds to the specific enum value. This should be an instance of a `CaseClass`. The `rawConstruct` with an empty field value should give you the desired instance.
Let me know if this helps 🙂
---
### Author:  [@adamw](https://softwaremill.community/u/adamw)
#### Post date: [February 3, 2023, 3:48pm UTC](https://softwaremill.community/t/instantiate-enum-from-string/111/3 "2023-02-03T15:48:29Z")
Maybe the `Show` typeclass and this test will help: [magnolia/SumsTests.scala at f5df7e63ce41375871524f442d0438aba698c6b7 · softwaremill/magnolia · GitHub](https://github.com/softwaremill/magnolia/blob/f5df7e63ce41375871524f442d0438aba698c6b7/src/test/SumsTests.scala#L54)
---
### Author:  [@sake92](https://softwaremill.community/u/sake92)
#### Post date: [February 6, 2023, 7:04am UTC](https://softwaremill.community/t/instantiate-enum-from-string/111/4 "2023-02-06T07:04:02Z")
Thank you very much Adam!
Seems like I was missing the `rawConstruct` and what it does… It’s really handy. 🙂
An example in Scastie if anyone needs it: [Scastie - An interactive playground for Scala.](https://scastie.scala-lang.org/MgUtg3gCQ6KtLzy40kSUMg)
```plaintext
import magnolia1.*
trait ParseString[T] {
def parse(str: String): T
}
object ParseString extends AutoDerivation[ParseString]:
def join[T](ctx: CaseClass[ParseString, T]): ParseString[T] = value =>
ctx.rawConstruct(Seq())
override def split[T](ctx: SealedTrait[Typeclass, T]): ParseString[T] = value =>
val subtype = ctx.subtypes.find(_.typeInfo.short == value).get
subtype.typeclass.parse(value)
/////
enum Color derives ParseString:
case Red
val tc = summon[ParseString[Color]]
println( tc.parse("Red") )
```