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Arrow v0.9.0 is now available

Arrow v0.9.0 is now available

We’re gearing up for some awesome things to hit the Arrow open source library, and with release 0.9.0 (now available), we’re paving the way for larger announcements and exciting features.

Arrow is an open source library that’s packed with data types and type classes that empower pure functional programming in Kotlin.

Noteworthy changes in 0.9.0 include:

Implemented Enhancements:

  • Fixes Coproducts type inference issue #1284.
  • Adds Semiring #1225.
  • Updates KotlinTest to the latest version and uses their provided Arrow matchers #854.
  • Updates KotlinTest #912.

Bug Fixes:

  • Fx Crash #1295.
  • Formatting issue on data type generated docs #1228.
  • Allow NonFatal control over exceptions for MonadError and Monadic comprehensions#153.

There’s a large list of changes, closed issues, and merged PRs in 0.9.0, please visit the official changelog for the complete overview.

We would like to give special thanks to the following contributors for this version (in no particular order):

For a full list of the contributors who have helped Arrow get to where it is today, please check out: Arrow Contributors. We’re always looking for additional help, please view the guidelines for contributing and take a look at the help-wanted issues. All levels are welcome and we offer 1:1 mentoring through Arrow’s Slack and Gitter channels.

If you would like to support Arrow, but don’t have the time to invest in contributing, consider picking up some Arrow swag! All proceeds are invested back into advancing the library.


The active development of Arrow is proudly sponsored by 47 Degrees, a Functional Programming consultancy with a focus on the Scala, Kotlin, and Swift Programming languages.

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