Meon - Neovim Configuration for C# Development

A fully-featured Neovim configuration optimized for C# / .NET development on macOS. Includes Roslyn LSP, debugging with netcoredbg, unit testing with Neotest, and 50+ carefully configured plugins.

Features

• Roslyn Language Server - Modern C# LSP with intelligent code analysis
• Integrated Debugging - netcoredbg with DAP UI, breakpoints, watches, and REPL
• Unit Testing - Neotest integration with test running and debugging
• .NET Build Integration - Direct dotnet build with quickfix error navigation
• VS Code Compatibility - Reads launch.json and settings.json configurations
• macOS ARM64 Optimized - Native Apple Silicon debugger and clipboard support

Requirements

• Neovim 0.9+
• .NET SDK 8.0+
• macOS (ARM64/Apple Silicon)
• Git
• fzf (for fuzzy finding)
• A Nerd Font (for icons)

Installation

# Backup existing config
mv ~/.config/nvim ~/.config/nvim.bak

# Clone this repository
git clone https://github.com/Eftiand/neovim-csharp-config.git ~/.config/nvim

# Open Neovim - plugins will install automatically
nvim

Structure

~/.config/nvim/
├── init.lua                 # Entry point
├── lazy-lock.json          # Plugin version locks
└── lua/meon/
    ├── core/
    │   ├── options.lua     # Editor settings
    │   └── keymaps.lua     # Key bindings
    ├── lazy.lua            # Plugin manager setup
    ├── plugins/
    │   ├── lsp/
    │   │   ├── roslyn.lua  # C# language server
    │   │   ├── lspconfig.lua
    │   │   └── mason.lua
    │   ├── nvim-dap.lua    # Debug adapter
    │   ├── nvim-dap-ui.lua # Debug UI
    │   ├── neotest.lua     # Test runner
    │   └── [...]           # 50+ plugin configs
    └── util/
        └── json5.lua       # VS Code launch.json parser

Key Bindings

Leader key: <Space>

LSP Navigation

Key	Action
gd	Go to definition
gD	Go to declaration
gi	Go to implementations
gr	Go to references
gt	Go to type definition
K	Hover documentation
<leader>ca	Code actions
<leader>rn	Rename symbol
<leader>D	Document diagnostics
<leader>d	Line diagnostics

Building & Debugging

Key	Action
<leader>bp	Build project (dotnet build)
<F5>	Continue / Start debugging
<F9>	Toggle breakpoint
<F10>	Step over
<F11>	Step into
<F8>	Step out
<leader>du	Toggle DAP UI
<leader>dw	Watch variable
<leader>dr	Open REPL

Testing (Neotest)

Key	Action
<leader>tr	Run nearest test
<leader>tf	Run file tests
<leader>td	Debug nearest test
<leader>ts	Toggle test summary
<leader>to	Open test output
<leader>tx	Stop tests

File Navigation

Key	Action
<leader>ff	Find files
<leader>fa	Find all files (including hidden)
<leader>fr	Recent files
<leader>fs	Live grep
<leader>fc	Grep word under cursor
<leader>ft	Find TODOs

Harpoon (Quick File Access)

Key	Action
<leader>ha	Add file to harpoon
<leader>hh	Open harpoon menu
<leader>1-4	Jump to harpooned file 1-4

Window Management

Key	Action
sh	Split vertical
sv	Split horizontal
se	Equal split sizes
sx	Close split
<leader>sm	Maximize/restore window

Other

Key	Action
jk	Exit insert mode
<leader>nh	Clear search highlights
<leader>rr	Reload config
T	Toggle floating terminal
:Ofinder	Open current file in Finder

C# Development Setup

Roslyn LSP

The configuration uses roslyn.nvim for C# language support. It automatically activates for .cs files with optimized settings:

• Background analysis scoped to open files (better performance)
• Inlay hints disabled for cleaner code view
• Full diagnostics from analyzers and compiler

Debugging

Debugging uses netcoredbg compiled for macOS ARM64. The debugger is bundled via netcoredbg-macOS-arm64.nvim.

To debug a project:

1. Create a .vscode/launch.json in your project (VS Code format supported)
2. Set breakpoints with <F9>
3. Start debugging with <F5>

Example launch.json:

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": ".NET Core Launch (console)",
      "type": "coreclr",
      "request": "launch",
      "program": "${workspaceFolder}/bin/Debug/net8.0/YourApp.dll",
      "args": [],
      "cwd": "${workspaceFolder}",
      "stopAtEntry": false
    }
  ]
}

Building

Press <leader>bp to build your solution. The command:

1. Reads .vscode/settings.json for dotnet.defaultSolution
2. Falls back to finding .sln or .slnx files
3. Runs dotnet build with live output
4. Opens quickfix list on errors

Unit Testing

Testing uses neotest with neotest-dotnet.

• <leader>tr - Run the test under cursor
• <leader>td - Debug the test under cursor
• <leader>ts - View test summary panel

Plugin Highlights

Core

• lazy.nvim - Plugin manager
• mason.nvim - LSP/DAP/linter installer
• nvim-treesitter - Syntax highlighting
• nvim-cmp - Autocompletion

Navigation

• fzf-lua - Fuzzy finder
• harpoon - Quick file switching
• leap.nvim - Fast cursor movement
• nvim-tree.lua - File explorer

UI

• onedark.nvim - Color scheme with C# enhancements
• lualine.nvim - Status line
• bufferline.nvim - Tab bar
• alpha-nvim - Dashboard

Development

• trouble.nvim - Diagnostics list
• gitsigns.nvim - Git integration
• todo-comments.nvim - Highlight TODOs
• which-key.nvim - Keybinding hints

macOS Features

• System clipboard - Uses pbcopy/pbpaste for seamless copy/paste
• ARM64 debugger - Native Apple Silicon netcoredbg
• Finder integration - :Ofinder reveals file in Finder
• Tmux navigation - Seamless pane switching with vim-tmux-navigator

Customization

Adding Plugins

Create a new file in lua/meon/plugins/ with a lazy.nvim spec:

return {
  "author/plugin-name",
  config = function()
    require("plugin-name").setup({})
  end,
}

Modifying Keymaps

Edit lua/meon/core/keymaps.lua to add or change key bindings.

Changing Theme

Edit lua/meon/plugins/colorscheme.lua to modify colors or switch themes.

Troubleshooting

Roslyn not starting

1. Ensure .NET SDK 8.0+ is installed: dotnet --version
2. Check Mason installed the server: :Mason and look for roslyn
3. View LSP logs: :LspLog

Debugger not working

1. Verify netcoredbg path exists: ~/.local/share/nvim/lazy/netcoredbg-macOS-arm64.nvim/netcoredbg/netcoredbg
2. Check launch.json syntax is valid
3. Ensure project is built before debugging

Plugins not loading

1. Run :Lazy to check plugin status
2. Try :Lazy sync to update plugins
3. Check for errors: :messages

License

MIT