halfsp is a Haskell language server that doesn't do much, and does it faster than HLS.

It ignores your source code, and expects you to manually:

• Produce analysis information in .hie files during compilation (using -fwrite-ide-info)
• Index the .hie files into a database using hiedb
• Do this every time your source code changes

If you do all that, it'll provide the following incredible list of...

At the moment, halfsp responds to the following LSP messages:

• workspace/symbol
• textDocument/hover
• textDocument/definition

halfsp will soon support the following...

• textDocument/{declaration, implementation, references}

halfsp will never support any other LSP messages.

As the name suggests, this project is a temporary hack. Specifically, it is intended to work around limitations in GHC recompilation-avoidance in the presence of Template Haskell, which can cause severe performance issues on large codebases with heavy use of TH.

For any project where you don't have this problem, use Haskell Language Server.