Scala example source code file (Meta.scala)

This example Scala source code file (Meta.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

bash, console, interpolation, meta, opt, selfupdate, spec, stdopts, string, unit

The Meta.scala Scala example source code

/* NSC -- new Scala compiler
 * Copyright 2005-2013 LAMP/EPFL
 * @author  Paul Phillips
 */

package scala.tools
package cmd

import nsc.io.File
import Interpolation._

/** Meta-options for command line tools.  We could have all kinds
 *  of additional goodness here, but for now it's completion and script
 *  generation.  See Demo for example usage.
 */
object Meta {
  trait Opt {
    def name: String
    def action: () => Unit
  }

  trait StdOpts {
    self: Spec with Interpolation =>

                                Bash.name   --> runAndExit(Bash.action())
    val selfUpdateName  = SelfUpdate.name   --| ;

    if (selfUpdateName.isDefined)
      runAndExit(SelfUpdate.action())

    /** I think we're as close as we can get to bundling completion with
     *  the program given the constraints imposed by bash.  This outputs
     *  the completion function to a tempfile and echoes ". /path/to/file"
     *  to the console.  Place it inside backtickes like `partest --bash`
     *  and voila, you have absorbed command completion.
     */
    object Bash extends Opt {
      val name    = "bash"
      val action  = () => {
        val file = File.makeTemp("scala.cmd.bash")
        file writeAll interpolate(bashTemplate)

        // Would be nice to print something like this but comments are
        // not always comments in bash, and breaking it is worse.
        // Console println ("# Run the following line, or issue the --bash command in `backticks`.")
        Console println (". " + file.normalize.path)
      }
    }

    /** Generates a very basic runner script.  It's called SelfUpdate
     *  because once it exists you can do something like
     *
     *    tools/scmp --self-update tools/scmp
     *
     *  and it will overwrite itself with the current version.
     */
    object SelfUpdate extends Opt {
      val name    = "self-update"
      val action  = () => {
        val file = File(selfUpdateName.get)
        file writeAll interpolate(runnerTemplate)
        file setExecutable true
        ()
      }
    }
  }
}