2011 11 15 scala as scripting language

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Date: 2011-11-15 Title: Scala as scripting language Tags: howto Slug: scala-scripting Created: 2011-11-15 Update: 2017-05-16

Problem

What is the solution that satisfies all these constraints:

• Write a script in scala (for example to process some files pdf files via apache poi library)
• You have dependencies on some external libraries. And want to solve the transitive dependencies.
• You want auto-completion to work in your favorite IDE (years ago I didn't realized that)

Solution

Analysis

Solution space

A solution must be along the lines:

• Add libraries on the classpath but you don't have transitive dependencies.
• Clearly you must use a proper build tool: sbt, maven for two purposes:
  • transitive dependencies
  • project generation in your IDE
  • use features like autocompletion (does it work in REPL?)

Resouces

• http://stackoverflow.com/questions/8254706/scala-as-a-shell-script-jars-on-the-classpath
• http://stackoverflow.com/questions/18812399/how-to-use-third-party-libraries-with-scala-repl
• http://stackoverflow.com/questions/6350876/running-a-scala-script-with-external-dependencies
• http://stackoverflow.com/questions/7600189/how-can-i-get-automatic-dependency-resolution-in-my-scala-scripts
• https://gist.github.com/sroebuck/1571464
• https://www.google.com/search?q=how+to+execute+scala+scripts+with+dependent+libraries

Deprecated

Solution 1 - Windows

Configure file type associations

As admin you should run the following in console:

assoc .scala=scalafile
ftype scalafile=<replace_with_scala_home>\bin\scala.bat -savecompiled "%1" %*

If you don’t want to always add the extension make sure .scala is executable by adding .scala to the PATHEXT variable

set PATHEXT=.scala;%PATHEXT%

(to make it long term you should actualy use this method http://www.itechtalk.com/thread3595.html)

Configure a folder for scripts

Now you can add to the path a place where you can put your .scala scripts

set PATH=<replace_with_scala_scripts_folder>;%PATH%

Create first script In <replace_with_scala_scripts_folder>\hi.scala you should add:

#!/bin/sh
exec scala "$0" "$@"
!#
println("hello world in scala script")
args foreach println
println("done")

Execute first script Now from anywhere you can execute:

hi 1 2 3

This will print

hello world in scala script
1
2
3
done

Resources

• 2017-10-17 - http://www.lihaoyi.com/post/ScalaScriptingandthe15MinuteBlogEngine.html