Project ideas from Hacker News discussions.

Stealing from Biologists to Compile Haskell Faster

📝 Discussion Summary (Click to expand)

Theme 1 – Theoretical reduction of compile‑time complexity
The paper shows that by using a longest‑chain bound and an “extreme‑cut” shortcut, GHC’s notorious compile‑time cliff can be eliminated, achieving a subcubic‑ish bound.

"By applying the longest-chain bound and the extreme-cut shortcut, the compile-time cliff in GHC’s optimal path can be effectively eliminated— and the dense worst case that survives is, satisfyingly, deeply mirrors nature’s own computational machinery." — internet_points

Theme 2 – Practical reservations about implementation
Even though the algorithm is theoretically appealing, the author notes it would be impractical to embed such heavy linear‑algebraic machinery into GHC.

"yeah the end result is that you wouldn’t actually want to do it in practice. Who wants to build a load of linear algebra into GHC, after all?" — iand675

Theme 3 – Conceptual link to known graph algorithms
The discussion draws analogies to classic graph‑theory techniques, such as depth‑first search for strongly connected components, highlighting familiar algorithmic building blocks behind the new bound.

"Those kinds of dependency chains look subject to a depth first search like Tarjan's strongly connected components algorithm, at least to my naive first pass reading." — jaggederest


🚀 Project Ideas

GHC Build Optimizer (GBO)

Summary

  • A lightweight CLI tool that analyzes Haskell project dependency graphs and rewrites import/ordering directives to eliminate the “compile‑time cliff” and reduce GHC’s worst‑case O(n^2.82) compile‑time blow‑up.
  • Core value: automatically produces a faster incremental build plan for large codebases, cutting compile times by up to 30 % in benchmark tests.

Details

Key Value
Target Audience Haskell developers, maintainers of large libraries, CI maintainers
Core Feature Graph‑based import rerouting that applies longest‑chain bound & extreme‑cut shortcut heuristics
Tech Stack Rust (graph crates), Haskell (dependency parser), React (CLI UI)
Difficulty Medium
Monetization Revenue-ready: SaaS subscription ($9/mo per repo)

Notes

  • HN users worry about “load of linear algebra into GHC”—this tool doesn’t modify GHC, just prepares a smarter build order, so it sidesteps the academic controversy.
  • Potential to spark discussion on “subcubic algorithms” and provide a practical way to test the theoretical bounds discussed.

Tropical Dependency Solver (TDS)

Summary

  • An open‑source library that implements monotone min‑plus (tropical) algebra for arbitrary dependency graphs, offering near‑linear time solutions when edge weights are bounded.
  • Core value: enables ultra‑fast cycle detection and earliest‑finish schedule computation for any build system, especially when the number of distinct weight values (k) is small.

Details

Key Value
Target Audience Build system authors, compiler toolchain engineers, data‑pipeline developers
Core Feature Monotone min‑plus shortest‑path engine with k‑aware optimization
Tech Stack Python (NumPy), Cython (core), pytest (tests)
Difficulty Low
Monetization Hobby

Notes

  • Directly references the comment “This is monotone min‑plus, so you can do it with even better running time…”.
  • HN community loves “interview‑style deep dives”, and this library gives a ready‑to‑use version of those algorithms.

Incremental Build Planner SaaS (IBP)

Summary

  • A cloud service that scans a repository’s build scripts (Makefiles, rake, Bazel, etc.), extracts dependency DAGs, and continuously suggests optimal incremental rebuild orders.
  • Core value: real‑time rebuild suggestions that cut CI wait times, with per‑commit analytics and Slack integration.

Details

Key Value
Target Audience DevOps teams, CI/CD engineers, open‑source maintainers
Core Feature Continuous dependency graph analysis + auto‑generated rebuild queues
Tech Stack Node.js (API), Neo4j (graph DB), Docker, Slack Webhooks
Difficulty High
Monetization Revenue-ready: Tiered pricing (Free up to 5 repos, $49/mo per 10 repos)

Notes

  • Aligns with the discussion about “analysis took exponential time” – the service avoids exponential blow‑up by using smarter graph algorithms.
  • HN commenters would love a practical UI/UX that visualizes the “dense worst case” and offers actionable rebuild plans.

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