PureScript compiler release v0.12.3

This is quite a small release, due to the fact that we are trying out a new 6-week release schedule; the next release will be on April 7.

Release notes and download links are on GitHub: https://github.com/purescript/purescript/releases/tag/v0.12.3

Thanks to everyone who contributed!

After this release, we will continue to focus on smaller quality-of-life improvements and bug fixes; we aren’t planning any big feature additions or big breaking changes any time soon.

Looking forward, we hope to release a version 0.13.0 with some small breaking changes soon: possibly the next release, or the one after that. I expect that the upcoming 0.13.0 will be the first major release which doesn’t necessitate changes in the majority of packages you are likely to be depending on.

In particular, @natefaubion has been leading work on an alternative PureScript parser based on Happy, which has significantly better performance and error reporting. This parser also provides a new concrete syntax tree representation, which should be ideal for various tools such as source code formatters. At the same time, we’re planning to make some minor language grammar deprecations: see GH-3517 for details. Note that this alternative parser is already capable of parsing the vast majority of real-world code, so these grammar deprecations are very unlikely to have much of an impact on your code.

Additionally, I’m planning to make documentation generation faster and more reliable by making some minor architectural adjustments, with the aim of making sure that it’s no longer possible to end up in a situation where normal compilation succeeds but documentation generation fails; see GH-3503 for more information.

This is by no means a complete list, it’s just to give you a flavour of some of the changes you can expect to see soon(ish). We’ve also started putting together a 0.13.0 milestone in the compiler issue tracker if you’d like a bit more detail.