[ I forgot to CC the Haskell Cafe in the first version of this, my apologies to Sven for getting this message twice ] On Tue, Dec 01 2020 16:22, Sven Panne wrote:
Well, some time ago I actually did, and it was a slightly frustrating experience: I'm using Spacemacs, and when I had a look last time, the haskell-language-server project was very young, and so was lsp-haskell.el. It took quite some time to read HOWTOs/compile/set up things etc., and the result was a bit underwhelming: Slow, using tons of memory, buggy, etc. Somehow this was to be expected from a new project, nevertheless it was a bit demotivating. Although it had a much smaller feature set, I was much more happy with Intero, it worked basically out-of-the-box. For most other IDEs, setting up a language mode is often just ticking a checkbox or pressing a button in an extension manager.
Things are actually much better now, especially for Emacs. Starting with Emacs 27, it now uses a proper JSON parser, making LSP operations much, much faster. Installation is also a breeze. For example, eglot uses HIE by default, so setting it up within Emacs (vanilla, though I doubt it would be much more complicated for Spacemacs) would just be (use-package eglot :hook (haskell-mode . eglot-ensure)) If you want to use ghcide instead of HIE, you can throw a (add-to-list 'eglot-server-programs '(haskell-mode . ("ghcide" "--lsp"))) in there somewhere. The procedure is very similar if you use lsp-mode instead of eglot.
Unless things have changed dramatically in the last few months, "easy" is definitely not the right word. Using the C++-LSP-Mode in Spacemacs takes a one-liner in the config ("Hey, please use clangd as the LSP backend") and an "apt install clangd" (if you don't have it already on your disk, which is very likely if you do development in C++ on Linux). I had a very different experience with Haskell and LSP.
The second part is more of a "why has no-one packaged this for Debian/Ubuntu derivatives" (which I'm not sure is true anymore, but I don't use either so I can't check) shortcoming than a Haskell LSP shortcoming, don't you think?