Kotlin Scripting Kickstarter

Kotlin Scripting Kickstarter demonstrates how Kotlin can be used as a scripting language.

Clone this project as a starting point for developing scripts in Kotlin.

Kickstarter Features

• Open the project in IntelliJ and develop scripts with full IDE support (completion, compilation, testing and debugging).
• Run scripts as standard unix scripts on the command line. e.g. #!/usr/bin/env kotlin-script.sh
• Edit scripts using any editor and they will be automatically compiled and cached when run.
• Use gradle to include libraries available in maven repositories in your scripts.
• Automatically bootstrap the environment. Just run any script and the Kotlin runitme and library dependencies will be downloaded automatically.

Quick Start

All you need to get going is a JDK installed and a unix-ish environment.

$ git clone https://github.com/andrewoma/kotlin-scripting-kickstarter kotlin-scripts
$ cd kotlin-scripts/
$ ./gradlew check copyToLib
$ export PATH=$PATH:`pwd`/kotlin
$ helloworld.kt
$ vi `which helloworld.kt` # Make some changes
$ helloworld.kt # See the results (takes a few seconds to compile)
$ helloworld.kt # Runs in around 100ms now that it is pre-compiled

Now open the cloned project in IntelliJ and edit and run the scripts within the IDE.

Examples

See histogram.kt for a sample script that generates a chart using arg4j for command line parsing and jfreechart for chart generation.

How it works

• The project itself is just a standard gradle project. It uses the gradle wrapper to bootstrap, automatically installing gradle, downloading libraries and compiling.
• Kotlin natively supports scripting to a limited extent, so it is valid to use #! (shebang) directives at the top of kotlin source files.
• The kickstarter exploits this to call kotlin-script.sh to launch scripts. The script runner checks to see if the script being run has been modified and if so, forces recompilation via gradle. Otherwise, the script is launched immediately.

Limitations

• Scripts must end with the .kt suffix as IntelliJ uses extensions to detect file types.
• Scripts must be declared in their own unique package or the main method will conflict with other scripts.
• The gradle koltin plugin seems to require that kotlin sources live in a directory called kotlin

Stuck behind an authenticating proxy?

Both git and gradle need to be configured to work via a proxy.

For git, add the following to ~/.gitconfig :

[http]
	proxy = http://<user>:<password>@<proxy_host>:<proxy_port>

For gradle, the following seems to work with both gradle and gradlew:

export GRADLE_OPTS='-Dhttp.proxyHost=<proxy_host> -Dhttp.proxyPort=<proxy_port> -Dhttp.proxyUser=<user> -Dhttp.proxyPassword=<password>'

Alternatives

kotlin-script provides traditional scripting support for Kotlin. The main advantage of the kickstarter approach is that supports full IDE development.

License

This project is licensed under a MIT license.