with-utf8 VS haskell-language-server

Invalid byte sequence sounds like a locale issue (see this blog post).

The real fix will happen when Data.Text moves from UTF-16 to UTF-8:

https://discourse.haskell.org/t/hf-tech-proposal-1-utf-8-enc...

Fortunately this proposal has been accepted, but I don't know the timeline for its implementation in GHC.

Until then, working with UTF-8 is kind of convoluted

https://serokell.io/blog/haskell-with-utf8

Also: libraries need to be fixed to accept Data.Text instead of String. IsString helps (it's a typeclass that contains all string types) but only if APIs take it instead of defaulting to String. Adding random string conversions to cope with legacy APIs is very annoying.

Agda is written in Haskell, and the quoted error message is a common problem with applications written in Haskell. You probably have an environment variable like LC_CTYPE or LC_ALL which is set to an unusual value. I'd try setting LANG, LC_CTYPE and LC_ALL to en_US.utf8.

without this I get a build error (see here

The advent of language server protocol made possible the creation of HLS (Haskell Language Server), and there are plugins for many editors, such as vscode-haskell, that allow you to have auto-complete, auto-import, and automatic function signatures—also available to your editor of choice. The whole feedback loop of editing, compiling, and running is greatly improved.

HLS 2.3.0.0 is currently broken on Windows.

The Haskell community has been focusing on tooling and IDE support in the last several years. Haskell-Language-Server is a huge improvment, so the experience is probably much better than you remember, but it'll still be a while before it catches up with Rust.

static-ls is a low memory language server for Haskell that serves as an alternative to (hls)[https://github.com/haskell/haskell-language-server] with less functionality by using statically generated information. It is intended for (Highly recommend hls instead if you aren't having these issues):

I think the corresponding HLS PR is https://github.com/haskell/haskell-language-server/pull/3462, so it isn't landed yet but hopefully can be part of a HLS release before too long. (I'm not sure if it will make it in to the very next release because we're due one out to support GHC 9.6.1 pretty soon.)