https://github.com/mkulak/ghosts
Nano library for F[Either[A, B]] syntax niceties
https://github.com/mkulak/ghosts
Last synced: 2 months ago
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Nano library for F[Either[A, B]] syntax niceties
- Host: GitHub
- URL: https://github.com/mkulak/ghosts
- Owner: mkulak
- Created: 2016-12-14T22:04:25.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2016-12-14T22:42:52.000Z (over 8 years ago)
- Last Synced: 2025-02-16T08:11:52.938Z (4 months ago)
- Language: Scala
- Size: 1.95 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# Ghosts
Nano library that provides syntax niceties on top of [cats](https://github.com/typelevel/cats)
## Rationale
Let's say you have `val v: F[Either[A, B]]` where `F` is some monad and you want to convert `Either` inside `F`.
You have following options:
* Use nested map calls:
```scala
v.map(_.map(f))
```
Pros:
* Pretty straightforward
* Type of outer monad doesn't change - it's still `F`
Cons:
* Code become clattered with multiple map/flatMap calls
* Use ```EitherT```:
```scala
import cats.data.EitherT
EitherT(v).map(f).value
```
Pros:
* Allows you to use it in for-comprehension
Cons:
* Type of outer monad changes - now it's `EitherT` instead of `F` and you can't directly pass your value to
function that expects `F'.
* Increased depth of monad's stack makes code harder to read
* Code is clattered with `EitherT`'s contructor calls
* Use this library:
```scala
import ghosts.either._
v.mapT(f)
```
Pros:
* Type of outer monad doesn't change: all methods of `F` are directly available to you,
you can freely pass it to any fuction that expects `F`.
* Depth of monad stack stays the same
Cons:
* Not suitable for use inside for-comprehension
## How to use
Add the following to your `build.sbt` file:
`libraryDependencies += "com.github.mkulak" %% "ghosts" % "0.0.1"`
## List of Dependencies
`org.typelevel" %% "cats" % "0.8.1"`