Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/kitlangton/neotype
A friendly newtype library for Scala 3
https://github.com/kitlangton/neotype
Last synced: 5 days ago
JSON representation
A friendly newtype library for Scala 3
- Host: GitHub
- URL: https://github.com/kitlangton/neotype
- Owner: kitlangton
- License: apache-2.0
- Created: 2023-03-02T03:23:34.000Z (almost 2 years ago)
- Default Branch: main
- Last Pushed: 2024-12-17T15:20:32.000Z (9 days ago)
- Last Synced: 2024-12-21T11:57:11.963Z (5 days ago)
- Language: Scala
- Size: 355 KB
- Stars: 174
- Watchers: 5
- Forks: 20
- Open Issues: 10
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# neotype
[![Release Artifacts][Badge-SonatypeReleases]][Link-SonatypeReleases]
[![Snapshot Artifacts][Badge-SonatypeSnapshots]][Link-SonatypeSnapshots]
[Badge-SonatypeReleases]: https://img.shields.io/nexus/r/https/oss.sonatype.org/io.github.kitlangton/neotype_3.svg "Sonatype Releases"
[Badge-SonatypeSnapshots]: https://img.shields.io/nexus/s/https/oss.sonatype.org/io.github.kitlangton/neotype_3.svg "Sonatype Snapshots"
[Link-SonatypeSnapshots]: https://oss.sonatype.org/content/repositories/snapshots/io/github/kitlangton/neotype_3/ "Sonatype Snapshots"
[Link-SonatypeReleases]: https://oss.sonatype.org/content/repositories/releases/io/github/kitlangton/neotype_3/ "Sonatype Releases"
A friendly newtype library for Scala 3.
```scala
"io.github.kitlangton" %% "neotype" % "0.3.8"
```
## Features
- Compile-time Checked Values
- Write validations as **plain, old Scala expressions**
- Helpful compilation errors (_see below_)
- No runtime allocations (Thanks to `inline` and `opaque type`)
- Integrates with other libraries (e.g. `zio-json`, `circe`, `tapir`, etc.)
## [5 Minute Video Tour](http://www.youtube.com/watch?v=6AxSX_WX7ek)
## Example
Here is how to define a compile-time validated Newtype.
```scala
import neotype.*
// 1. Define a newtype.
object NonEmptyString extends Newtype[String]:
// 2. Optionally, define a validate method.
override inline def validate(input: String): Boolean =
input.nonEmpty
// 3. Construct values.
NonEmptyString("Hello") // OK
NonEmptyString("") // Compile Error
```
Attempting to call `NonEmptyString("")` would result in the following compilation error:
```scala
Error: /src/main/scala/examples/Main.scala:9:16
NonEmptyString("")
^^^^^^^^^^^^^^^^^^
—— Newtype Error ——————————————————————————————————————————————————————————
NonEmptyString was called with an INVALID String.
input: ""
check: input.nonEmpty
———————————————————————————————————————————————————————————————————————————
```
## Integrations
Neotype integrates with the following libraries:
- **JSON**
- [zio-json](https://github.com/zio/zio-json)
- [play-json](https://github.com/playframework/play-json)
- [jsoniter](https://github.com/plokhotnyuk/jsoniter-scala)
- [circe](https://github.com/circe/circe)
- **DATABASE**
- [doobie](https://github.com/tpolecat/doobie)
- [quill](https://github.com/zio/zio-quill)
- **MISCELLANEOUS**
- [zio-test](https://github.com/zio/zio) `DeriveGen`
- [zio-config](https://github.com/zio/zio-config)
- [zio-schema](https://github.com/zio/zio-schema)
- [tapir](https://github.com/softwaremill/tapir)
- [chimney](https://github.com/outr/chimney)
- [caliban](https://github.com/ghostdogpr/caliban)
### ZIO Json Example
```scala
import neotype.*
type NonEmptyString = NonEmptyString.Type
object NonEmptyString extends Newtype[String]:
override inline def validate(value: String): Result =
if value.nonEmpty then true else "String must not be empty"
```
```scala
import neotype.interop.ziojson.given
import zio.json.*
case class Person(name: NonEmptyString, age: Int) derives JsonCodec
val parsed = """{"name": "Kit", "age": 30}""".fromJson[Person]
// Right(Person(NonEmptyString("Kit"), 30))
val failed = """{"name": "", "age": 30}""".fromJson[Person]
// Left(".name(String must not be empty)")
```
By importing `neotype.ziojson.given`, we automatically generate a `JsonCodec` for `NonEmptyString`. Custom
failure messages are also supported (by overriding `def failureMessage` in the Newtype definition).
Note that `import neotype.interop.ziojson.given` needs to be in the same file as `Person`, *not* `NonEmptyString`.
The generated `JsonCodec` is not made available to the entire project, but only to the file where it is imported.