The PostgreSQL community has announced the release of PL/Haskell v6.0, the latest version of the extension that lets developers write PostgreSQL functions in the Haskell functional programming language. The release builds on the project's goal of bringing Haskell's strong type system and functional idioms directly into stored procedures and triggers, and it is available now via the project's distribution channels.
Here are the concrete changes in this release:
- Added the ability to work with range types, allowing Haskell functions to accept and return PostgreSQL range values directly.
- Published packages for Ubuntu and Fedora, so users can install the extension straight from the
rpmandaptrepositories. - Noted a known bug in the GHC libraries on Fedora 44, with a documented workaround for users on that release.
- Maintained the existing issue tracker for bug reports and feature requests via GitHub.
The headline feature, range type support, matters because ranges (int4range, tsrange, daterange, and others) are a distinctive PostgreSQL capability frequently used for scheduling, availability windows, and interval logic. Previously, bridging those values between SQL and Haskell required manual conversion or intermediate representations; v6.0 lets functions handle them natively, which reduces boilerplate and the risk of marshalling errors in code that already leans on Haskell's type safety.
The packaging work is equally practical. Being able to install through standard apt and rpm tooling lowers the setup cost for teams that already manage PostgreSQL extensions through their system package managers, instead of building from source. Developers on Fedora 44 should review the noted GHC library issue before upgrading, since the workaround may be needed to get the extension running cleanly. As always, problems and feature requests can be filed as GitHub issues.
Source: https://www.postgresql.org/about/news/plhaskell-v60-released-3388/