haskell-dev-base

A dev container template for Haskell development.

What's included

Component	Version
GHC	9.6.7
Cabal	3.10.3.0
Haskell Language Server (HLS)	2.12.0.0

Shell: Zsh (default)

System tools: build-essential, curl, git, pkg-config, libffi-dev, libgmp-dev, libssl-dev, zlib1g-dev, direnv, socat, procps

VS Code extensions installed automatically:

• Haskell — HLS integration
• Haskell Syntax Highlighting
• GHCi
• direnv
• Error Lens
• EditorConfig
• Markdown All in One
• markdownlint

Prerequisites

• Docker
• VS Code with the Dev Containers extension

Using this template

1. Click Use this template on GitHub to create a new repository from this template.
2. Clone your new repository and open it in VS Code.
3. When prompted, click Reopen in Container (or run the command Dev Containers: Reopen in Container).
4. The container will build and run the post-creation setup automatically. This may take several minutes on first build.

Project structure

.
├── .devcontainer/
│   ├── devcontainer.json   # Dev container configuration
│   ├── docker-compose.yml  # App services
│   ├── Dockerfile          # Haskell toolchain setup
│   └── post-create.sh      # Post-creation setup script
├── .editorconfig           # Consistent editor formatting rules
└── .gitignore              # Haskell, Cabal, and VS Code ignores

Customising the template

Changing GHC or HLS versions: Update the version variables in .devcontainer/Dockerfile and update the versions mentioned in .devcontainer/post-create.sh welcome message accordingly.

Changing Cabal version: Update BOOTSTRAP_HASKELL_CABAL_VERSION in .devcontainer/Dockerfile.

Adding Cabal packages as dependencies: Create a cabal.project and .cabal package file at the root of the repository after cloning the template.

Using direnv for per-project environment variables: Add a .envrc file to the project root. direnv is pre-installed and hooked into both Bash and Zsh.