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Ammonite API

The Ammonite API consists in instances of several classes, that are created by Ammonite or almond, and allow you to interact with the REPL. These instances are accessible either by their name, from the REPL, like interp, or via implicits, like implicitly[ammonite.interp.api.InterpAPI].

The following instances are available:

• interp, which is a ammonite.interp.api.InterpAPI,
• repl, which is a ammonite.repl.api.ReplAPI.

InterpAPI

InterpAPI allows to

• load new dependencies or compiler plugins,
• add repositories for dependencies,
• add exit hooks,
• configure compiler options.

Load dependencies

interp.load.ivy accepts one or several coursier.Dependency.

Load simple dependencies

interp.load.ivy("org.platanios" %% "tensorflow-data" % "0.4.1")

Load dependencies while adjusting some parameters

interp.load.ivy(
  // replace with linux-gpu-x86_64 on linux with nvidia gpu or with darwin-cpu-x86_64 on macOS 
  ("org.platanios" %% "tensorflow" % "0.4.1").withClassifier("linux-cpu-x86_64")
)

The dependencies can then be used in the cell right after the one calling interp.load.ivy.

Note that in the case of simple dependencies, when directly entering code in a notebook, the following syntax is preferred and allows to use the dependency in the current cell rather than the next one:

import $ivy.`org.platanios::tensorflow-data:0.4.1`

Load compiler plugins

interp.load.plugin.ivy accepts one or several coursier.Dependency.

interp.load.plugin.ivy("org.spire-math" %% "kind-projector" % "0.9.9")

The plugins can then be used in the cell right after the one calling interp.load.plugin.ivy.

Note that when directly entering code in a notebook, the following syntax is more concise, and allows to use the compiler plugin in the current cell:

import $plugin.$ivy.`org.spire-math::kind-projector:0.9.9`

// example of use
trait T[F[_]]
type T2 = T[Either[String, ?]]

Add repositories

One can add extra coursier.Repository via

import coursierapi._

interp.repositories() ++= Seq(
  MavenRepository.of("https://nexus.corp.com/content/repositories/releases")
    .withCredentials(Credentials.of("user", "pass"))
)

Add exit hooks

interp.beforeExitHooks += { _ =>
  // called before the kernel exits
}

Configure compiler options

// enable warnings
interp.configureCompiler(_.settings.nowarn.value = false)

ReplAPI

ReplAPI allows to

• access the pretty-printer and customize its behavior,
• access the latest thrown exception,
• access the command history,
• request the compiler instance to be re-created,
• get the current compiler instance,
• get the current imports,
• evaluate code from strings or files, and lastly
• get the class names and byte code of the code entered during the current session.

Pretty-printer

class Foo(val x: Int)

repl.pprinter() = {
  val p = repl.pprinter()
  p.copy(
    additionalHandlers = p.additionalHandlers.orElse {
      case f: Foo =>
        pprint.Tree.Lazy(_ => Iterator(fansi.Color.Yellow(s"foo: ${f.x}").render))
    }
  )
}

Latest thrown exception

repl.lastException // last thrown exception, or null if none were thrown

Command history

repl.history // current session history
repl.fullHistory // shared history

Refresh compiler instance

repl.newCompiler()

Get compiler instance

repl.compiler // has type scala.tools.nsc.Global

Get current imports

repl.imports

Evaluate code

repl.load("val a = 2")

Byte code of REPL inputs

repl.sess.frames.flatMap(_.classloader.newFileDict).toMap
// Map[String, Array[Byte]], keys: class names, values: byte code