From Rosetta Code
This is an example of a library. You may see a list of other libraries used on Rosetta Code at Category:Solutions by Library.

Wren-ioutil is a module which supplements the functionality of the IO module. It consists of 3 classes: FileUtil, Input and Output which supplement File, Stdin and Stdout respectively.

It is the eighteenth in a series of modules (listed on the language's main page) designed to assist with writing Rosetta Code tasks so the same code does not have to be written or copy/pasted time and time again thereby bloating a task's script code unnecessarily.

To use it you need to copy the source code (in the talk page) to a text file called ioutil.wren and place this in the same directory as the importing script so the command line interpreter can find it.

Wren-ioutil has dependencies on the IO and OS modules which are part of Wren-cli's standard library. As such it can only be used in a Wren-cli script.