A development container for Haskell

This is an opinionated Development Container for Haskell.

Features

The development container has the following features:

• Pre-configured Cabal, Stack and HLS: Cabal, Stack and HLS come pre-installed and pre-configured.
• Pre-installed development tools: The development container comes with a number of generic (Git, Neovim, SSH, etc.) and Haskell-specific (ormolu, implicit-hie, retrie, etc.) development tools pre-installed.
• Integrated GHCi: The development container comes with an integrated GHCi shell.
• Offline support: Hoogle and Hackage are included locally in the container, meaning you do not need an internet connection to find definitions or read documentation.

To open the integrated GHCi shell, press the yellow lambda symbol in the top-right corner. To search Hoogle, press Alt + Shift + H.

Using with Visual Studio Code

Follow the steps below to use the Development Container with Visual Studio Code:

1. Follow the Getting Started instructions to configure Visual Studio Code and Docker for use with Development Containers.
2. Clone this repository. You can checkout another branch to use a different version.
3. Open the repository using Visual Studio Code.
4. Click Reopen in Container when Visual Studio Code prompts you, or open the command palette (Ctrl + Shift + P or Cmd + Shift + P) and execute the command >Dev Containers: Reopen in Container.

Warning

Building the image initially may take a long time (anywhere from 15 minutes up to several hours, depending on the speed of your machine and your internet).

How does it work

Visual Studio Code supports Development Containers (i.e. using a Docker image as a development environment). It automates the hassle of setting up a proper development environment.

Troubleshooting

This section lists some common problems, and possible ways to fix these problems. If you encounter an issue not listed here, or if the fixes listed do not work for you, please open an issue.

• Definitions from other files are not found.
  • Try running stack install in the project directory.
• Definitions from dependencies are not found.
  • Try restarting Visual Studio Code.
• Stuck on Processing ../...
  • Try running stack build in the project directory.
• Code completion and/or checking is not working.
  • Try restarting Visual Studio Code.
  • Try running stack install in the project directory.
• Something else does not work.
  • Try restarting Visual Studio Code.
  • Open an issue on GitHub.

Installed software

The container comes with the following (relevant) software pre-installed:

• debian:bookworm-slim as a base image;
• GNU Bash;
• Git;
• Neovim;
• GHCUp;
• The Glasgow Haskell Compiler (GHC);
• The Haskell Language Server (HLS);
• Stack;
• Cabal.

Following VSCode extensions are automatically installed after container is started:

• Haskell;
• Haskell GHCi Debugger Adapter;
• Integrated Haskell Shell;
• Hoogle for VSCode;
• Hackage Theme;
• Code Spell Checker;
• VSCode PDF;
• YAML;
• Markdown All in One.

The development container also comes pre-installed with a number of useful packages.