README.md

Effekt Exercises

Materials for the <Programming> 2025 tutorial Effekt: Lexical Handlers in Action.

Tasks

All the tasks are Literate Effekt files (*.effekt.md) in the tasks/ subfolder.

1. hurl & stages
2. sudoku
3. event
4. BONUS challenge (domain modelling using effect handlers)
5. BONUS pull (bidirectional effects)

Important links

• Effekt Discord https://discord.gg/dWUaFX7xtr (ask questions, report bugs)
• Language Tour https://effekt-lang.org/tour (short bite-sized tutorials)
• Playground https://effekt-lang.org/playground (shareable client-side playground)

Install Effekt

Tip

If you prefer working online, the exercises are also available at https://effekt-lang.org/docs/exercises

However for larger / independent projects, we highly recommend you install Effekt on your machine.

Otherwise, here's how to install Effekt:

1. Install VSCode, JVM (≥11) & Node.js (≥ 16)
2. Clone this repository
3. Install the Effekt extension in VSCode (https://marketplace.visualstudio.com/items?itemName=effekt-lang.effekt, should get offered if you open the repository in VSCode)
4. Open some *.effekt or *.effekt.md file in VSCode
5. Install Effekt via the pop-up (or use npm install -g @effekt-lang/effekt)
6. Run a file using a |> Run code lens over a main function or by running effekt <path-to-file>

Nix

If you use Nix, the automatic installer won't work, but we've attached a flake.nix file to this repository, so you can use nix develop.