Scala REPL in Gradle

Question

Gradle scala integration currently does not offer REPL functionality. How to ergonomically run scala REPL from Gradle using the appropriate classpath?

Answer 1

Minimum build.gradle :

 apply plugin: 'scala' repositories{ mavenCentral() } dependencies{ compile "org.scala-lang:scala-library:2.11.7" compile "org.scala-lang:scala-compiler:2.11.7" } task repl(type:JavaExec) { main = "scala.tools.nsc.MainGenericRunner" classpath = sourceSets.main.runtimeClasspath standardInput System.in args '-usejavacp' } 

Confirm this answer to explain how to direct stdin with standard input and use REPL the correct path to the args path.

Note that the scala-compiler library is a dependency. This is where scala.tools.nsc.MainGenericRunner found.

On the console, to run REPL, you need several parameters:

• --no-daemon if you are using the Gradle daemon. Currently REPL does not respond to keystrokes if they are launched from the daemon.

• --console plain . A popular but lower alternative is --quiet . If run without one of these options, the REPL query is dirty with the Gradle Progress Report. The advantage of --console plain is that it also adjusts the readline behavior, so rlwrap not required.

The full command to run REPL is gradle repl --console plain --no-daemon , so creating an alias in your shell makes sense.