Neovim and Language Server Protocol (LSP)

Language Server Protocol (LSP) helps computer programmers working on editors and get information about the languages they are working on. The LSP is an interface between editors (files, codes, cursor, state of code) and language server(s) running on the computer and the language server provides information on the state of the code.

Neovim LSP Setup Native and options with Plugins

Source: Neovim LSP Myth: You DON’T Need Plugins (The 5-Tier Setup) - smnatale - YouTube

Video covers setting up LSP in Neovim with default functionality and no plugins. It then goes through options that add more automation with plugins 1. nvim-lspconfig, 2. mason.nvim, 3. mason-lspconfig, 4. mason-tool-installer and when to use the automation those plugins help with.

Option 1: Native Set up, No Plugins

Example using Lua LSP

1. Install Lua language server on your system
2. Copy lua_ls.lua from nvim-lspconfig repository to the Neovim configuration directory
3. In init.lua add vim.lsp.enable({"lua_ls"})
4. Repeat for other languages as needed

Option 2: with LSP configuration plugin

1. Reuse LSP configurations maintained by the community using the nvim-lspconfig plugin. Add plugin to Neovim configuration.
2. Optionally, override any settings.
3. Install language servers you want to use on your system
4. In init.lua add vim.lsp.enable({"lua_ls", "ts_ls"}) for Lua and Typescript or choose appropriate LSP for the language.

Option 3: with LSP installer and LSP configuration plugins

1. Set up Option 2. Use mason.nvim to install relevant language servers and in Neovim use :Mason
2. Use mason-lspconfig to set which LSPs to install and enable LSPs.
3. Update Neovim configuration to set which LSPs to install and enable:

require("mason-lspconfig").setup({
    ensure_installed = {"lua_ls", "ts_ls"}
})

1. Use mason-tool-installer to set which should be installed and not installed (for example, you manage the install yourself).

Rust Setup for Neovim

Source: Rust Setup For Neovim (ft BashBunni) #bash2basics - YouTube with TJ DeVries

Installing rust

• Use rustup.rs
  • rustc, cargo
• Get Rust LSP: rust-analyzer

New rust project, look at rust files

# Install rust LSP
rustup component add rust-analyzer

# Create new project
cargo new projectname

# run project1
cd projectname
cargo run

Can prefer cargo run to check for errors

Getting lspconfig setup

What is an LSP?

• Language Server Protocol (LSP)
  • Just a program
• Helps your editor figure syntax of language, helps navigate

Example lsp.lua

lspconfig.rust_analyzer.setup {
  capabilities = capabilities,
  on_attach = on_attach,
  -- so it can find rust-analyzer
  cmd =  {
    "rustup", "run", "stable", "rust-analyzer"
  }
}

• Restart nvim
• Find help at lspconfig site or the LSP server site for the language on how to integrate

Testing out Rust basics

main.rs

fn main() {
    println!("{} world", "hello");
}

fn truthy() -> bool {
    return false;
}

#[cfg(test)]
mod test {
    use super::truthy;

    #[test]
    fn test_something() {
        assert_eq!(truthy(), true);
    }
}

Writing rust tests, cargo-watch

cargo test

# Install tool to monitor for file changes and then do tests
cargo install cargo-watch
# Tell cargo watch to run tests on source changes
cargo watch -x test
# During later changes to source code, tests will automatically be run