From 39a3b9fd63f19ccc7b69860a7a654763b0920dbd Mon Sep 17 00:00:00 2001
From: pacien
Date: Fri, 29 Mar 2019 17:48:24 +0100
Subject: write readme

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 _Some functional sweetness for Java._
 
+This library provides useful monads that are not present in the JDK.
+The defined types and API are minimal and highly composable with the standard ones, avoiding re-inventing them.
+
+
+## Usage
+
+The Javadoc for the latest snapshot version is available online [here][javadoc].
+
+[javadoc]: https://javadoc.jitpack.io/org/pacien/lemonad/master-SNAPSHOT/javadoc/
+
+### Attempt
+
+The `Attempt` monad represents a computation which can be either successful or failed.
+It allows the transformation of results and the recovery of errors in a pipeline,
+similarly to [Scala's `Try`][scala-try] or [Java's `CompletableFuture`][java-completable-future].
+
+This monad does __not__ require the error type to be a `Throwable`,
+the use of which being problematic in performance-sensitive contexts.
+
+[scala-try]: https://www.scala-lang.org/api/2.12.8/scala/util/Try.html
+[java-completable-future]: https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/concurrent/CompletableFuture.html
+
+```java
+import static org.pacien.lemonad.attempt.Attempt.*;
+
+(tree.hasLemon() ? success(tree.getLemon()) : failure("No lemon."))
+  .mapFailure(error -> store.buyLemon())
+  .mapResult(this::makeLemonade)
+  .ifSuccess(this::drink);
+```
+
+### Validation
+
+The `Validation` monad represents a validation of a subject which can be either valid or invalid.
+In the latter case, the monad wraps one or multiple validation errors in addition to the subject of the validation.
+
+The `Validator` functional interface represents a function which performs verification operations on a supplied subject and returns
+a `Validation`.
+`Validator`s can be composed to perform verifications against multiple criteria and obtain an aggregated `Validation`.
+
+```java
+import static org.pacien.lemonad.validation.Validator.*;
+
+var validator = validatingAll(
+  ensuringPredicate(not(Lemon::isRotten), "Bad lemon."),
+  validatingField(Lemon::juiceContent, ensuringPredicate(mL -> mL >= 40, "Not juicy.")));
+
+validator.validate(lemon)
+  .ifValid(this::makeLemonade)
+  .ifInvalid(errors -> makeLifeTakeTheLemonBack());
+```
+
+
+## Setup
+
+_lemonad_ requires Java 11 or above.
+Binaries are compiled by and distributed through [JitPack][jitpack-page].
+
+[jitpack-page]: https://jitpack.io/#org.pacien/lemonad
+
+### Gradle (`build.gradle`)
+
+```groovy
+repositories {
+  maven { url 'https://jitpack.io' }
+}
+
+dependencies {
+  implementation 'org.pacien:lemonad:master-11a6ff0260-1'
+}
+```
+
+### Maven (`pom.xml`)
+
+```xml
+<project>
+  <repositories>
+    <repository>
+      <id>jitpack.io</id>
+      <url>https://jitpack.io</url>
+    </repository>
+  </repositories>
+ 
+  <dependency>
+    <groupId>org.pacien</groupId>
+    <artifactId>lemonad</artifactId>
+    <version>master-11a6ff0260-1</version>
+  </dependency>
+</project>
+```
+
 
 ## License
 
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