Haskell.nix alternative: build Plutus contracts with Dream2Nix

[GENERAL] Name and surname of main applicant

Andrea Ciceri

[GENERAL] Are you delivering this project as an individual or as an entity (whether formally incorporated or not)

Entity (Not Incorporated)

[GENERAL] Please specify how many months you expect your project to last (from 2-12 months)

12

[GENERAL] Please indicate if your proposal has been auto-translated into English from another language

No

[GENERAL] Summarize your solution to the problem (200-character limit including spaces)

Dream2Nix is a modular framework for building software with Nix, already supporting various languages.

This project aims to add Haskell support to Dream2Nix, with a focus on building Plutus contracts.

[GENERAL] Does your project have any dependencies on other organizations, technical or otherwise?

Yes

[GENERAL] If YES, please describe what the dependency is and why you believe it is essential for your project’s delivery. If NO, please write “No dependencies.”

If our work is rejected upstream, we reserve the right to use a fork. We will, however, strive to incorporate everything into the official repository.

[GENERAL] Will your project’s output/s be fully open source?

Yes

[GENERAL] Please provide here more information on the open source status of your project outputs

Yes, Dream2Nix is open source under the MIT license, and this proposal aims to have all contributions merged into the main repository (incrementally through several PRs).

If separate repositories are necessary, they will also be MIT licensed.

[METADATA] Horizons

Developer Tools

[SOLUTION] Please describe your proposed solution

A minimal proof of concept (PoC) for building Haskell programs with Cabal in Dream2Nix already exists. The goal is to expand (or rewrite) this module to support building generic Cabal projects using a "granular" approach (as defined by Dream2Nix), where each dependency is treated as a separate derivation, allowing for granular overriding.

Initially, we will focus on simple Cabal projects, but once the project reaches a stable status, we will shift to targeting real Cardano smart contracts.

Dream2Nix already includes examples for other languages and CI checks to validate these examples. We will integrate new Haskell examples and ensure they are built through updated CI checks.

[IMPACT] Please define the positive impact your project will have on the wider Cardano community

This proposal increases the variety of technologies available for building Cardano applications. By leveraging a modular and generic framework, we can collaborate with non-Cardano developers to enhance the tooling.

Additionally, all projects utilizing haskell.nix could potentially benefit from this initiative.

[CAPABILITY & FEASIBILITY] What is your capability to deliver your project with high levels of trust and accountability? How do you intend to validate if your approach is feasible?

We are both expert Nix developers with significant experience and a strong track record of contributions to several related projects, including:

• haskell.nix
• cabal
• dream2nix

Additionally, we serve as maintainers for numerous packages within the nixpkgs ecosystem and other nix-related projects, showcasing our deep understanding of the Nix environment and its package management. Our expertise extends to the Cardano blockchain, where we have actively contributed to projects such as:

• cardano.nix
• spo-anywhere
• cardanow
• ytxp-lib
• sc-tools
• blockfrost-backend-ryo

These contributions demonstrate our capability to navigate complex systems and deliver high-quality software solutions.

To ensure our approach is feasible and to establish trust and accountability, we will employ strategies such as prototyping and iteration to refine our solution based on feedback, alongside transparent budgeting that outlines all expected costs. We will provide regular updates regarding the status of the project, including financial reports that reflect actual spending versus the budget. Our previous project management experience has equipped us with the skills to lead teams effectively, ensuring that resources are managed efficiently and responsibly. Together, our combined expertise and established processes demonstrate our capability to deliver this project with high levels of trust and accountability.

[PROJECT MILESTONES] What are the key milestones you need to achieve in order to complete your project successfully?

Milestone name: Settlement

Outputs:

• New Dream2Nix module scaffold (potentially starting from the existing PoC module).
• At this stage, the module is not yet "granular"—everything is part of a single derivation.
• Well-designed module interface (i.e., module options).
• Automatic documentation generation is functional.
• Able to build a simple Cabal project.

Acceptance Criteria: -

• A basic Cabal project successfully builds using the new module.

Evidence:

• A CI job demonstrating that an example Cabal project in the examples folder builds successfully (or a separate repository with clear build instructions).

Milestone name: Granularity

Outputs:

• The module is now capable of building packages by internally creating derivations for each dependency within the package set (alternatively, a new separate module for granular building may be introduced).
• Each derivation can be individually overridden.

Acceptance Criteria:

• Able to build with granular control by overriding individual dependencies.

Evidence:

• A CI job showing the ability to override single dependencies in an example added to the Dream2Nix repository (or a separate repository with build instructions).

Milestone name: Plutus Contracts

Outputs:

• The module can now build Plutus contracts.
• We may create a separate, specialized module to wrap the previous one, configuring shared options useful for building Plutus contracts.

Acceptance Criteria:

• Able to build a basic Plutus contract.

Evidence:

• A CI job demonstrating successful Plutus contract building (if acceptable, added to the repository’s examples, otherwise, in a separate repository with instructions).

Milestone name: Closeout and Video

Outputs:

• A video providing an overview of the project, demonstrating how to package a Plutus contract with Dream2Nix.
• Polished documentation that refines the automatically generated content.

Acceptance Criteria:

• The video is published online.

Evidence:

• The video itself.

[RESOURCES] Who is in the project team and what are their roles?

Andrea Ciceri - https://github.com/aciceri

Andrea has over 5 years of experience in blockchain technology, primarily focused on Cardano, with earlier work in Ethereum. For the past 3 years, he has worked as a DevOps Engineer and Nix expert, crafting solutions for the Cardano ecosystem. His passion for Nix led him to co-found the Nix Milano meetup, the first recurring Nix-focused community event in Italy.

Andrea has contributed to and led several open-source Cardano projects, including:

• cardano.nix: A set of NixOS modules for deploying Cardano services, featuring autogenerated documentation and VM-based tests.
• spo-anywhere: A tool for deploying NixOS machines running a stake pool on any Linux server.
• cardanow: A service that generates recurring snapshots for various Cardano-related applications, including cardano-node, cardano-db-sync, and Kupo.

He has already shown to know dream2nix by implementing basic support for purescript/spago: https://github.com/nix-community/dream2nix/commits/main/modules/dream2nix/WIP-spago

Alberto Fanton - https://github.com/albertodvp

Alberto is a blockchain engineer with 7 years of professional experience working in both national and international contexts. Currently, he is working as a freelancer, dedicating his expertise to developing Cardano-based projects with a focus on distributed systems and blockchain development. His experience in various companies in Milan has given him deep familiarity with the local tech ecosystem and allowed him to build an extensive professional network.

An active member of the Milan tech community, Alberto co-founded the Nix Milano meetup, is a frequent attendee of the Open Source Saturday events and regularly participates in the Haskell Milano meetup. His involvement in these communities has helped foster a thriving developer environment in Milan, with a focus on functional programming, open-source contributions, and blockchain innovation.

In addition to his professional work, Alberto is a dedicated contributor to the open-source ecosystem. His notable contributions include:

• ytxp-lib
• sc-tools
• Cardanow
• Cabal

He is also a Nixpkgs maintainer, contributing to the development of one of the most advanced package management systems. Alberto’s strong presence in the open-source community, combined with his extensive network and local expertise, positions him well to support the growth of the Cardano ecosystem in Milan.

[BUDGET & COSTS] Please provide a cost breakdown of the proposed work and resources

Hourly salary: 50 EUR/hour

Estimated hours: 2 days per week (overall among all the components) for 12 months (52 weeks) = 832 hours

Total development cost: 41600.00 EUR (138666.67 ADA at 0.3 EUR/ADA)

Contingency: ~7.5%

Grand total: 145000.00 ADA

[VALUE FOR MONEY] How does the cost of the project represent value for money for the Cardano ecosystem?

The value for money is expected to be optimal, as costs are solely based on development hours.