Relax: JIT compiler for Rust to reduce build times

(makepad.github.io)

101 points | by adamnemecek 1 day ago

13 comments

  • _cart 2 hours ago

    Pretty wild to me that AI has enabled the commoditization of one of the gnarliest engineering problems. Over the course of just a month, we now have three "viable" AI-driven iteration-focused Rust compilers: - https://github.com/makepad/relax - https://github.com/DioxusLabs/rustd/ - https://github.com/indexable-inc/blaze

  • faresahmed 5 hours ago

    Somehow always, someone somewhere rediscovers that cutting down the time between coding and code execution makes our lives easier and to a degree be able to write better programs.

    Perhaps the earliest and best attempt was Lisp's computational model. Since then, the idea manifested itself again[1], again[2], and again[3] in different forms.

    [1]: Inventing on Principle, Bret Victor: https://www.youtube.com/watch?v=PUv66718DII

    [2]: REPL-Driven Development, Stuart Halloway: https://vimeo.com/223309989

    [3]: LIVE, Live Programming workshop: https://liveprog.org/

    • pjmlp 3 hours ago

      Spot on, hence why having a mix of JIT/AOT tooling is such a great experience.

      Besides your examples, Eiffel, Oberon, Java, .NET, C++ (yep even for it), Cedar, Standard ML, OCaml, Haskell, Prolog, BASIC, Forth

      • Capricorn2481 4 hours ago

        This implies that Rust build times haven't been a topic of discussion for the last 10 years. They don't have long build times just for funsies, Rust is completely different from Lisp.

      • jkelleyrtp 4 hours ago

        I built something similar - tbd on maintaining it - but I got Rust Analyzer emitting code and as well as running in the web. This new concept of rust compile daemon is pretty sick.

        Can build and iterate on Rust in the browser!

        https://dioxuslabs.github.io/rustd/

        • cedws 1 hour ago

          Rust is a nice language but it’s so heavy. Since our company switched from Go I’ve had to become used to my laptop being burning hot and stuttering whilst trying to do anything during compilation.

          • Sytten 5 hours ago

            We have had good experience with kache so far to speedup builds in CI and local

            • n_u 5 hours ago

              How does it compare to sccache ?

            • scottmas 3 hours ago

              Anyone know what effect it has on targets/ bloat and dev disk usage?

              • rikarendsmp 1 hour ago

                It should be lower, but I haven't optimized it too hard on disk size. It's about iteration latency for LLM's.

              • jonstewart 4 hours ago

                I've been using "mr boxington" (mbx) the past several weeks and it's been a big help. https://mr-boxington.jdx.dev/

                • ricardobeat 2 hours ago

                  > 0 crates.io dependencies, in 438k lines of Rust

                  It's great to have zero deps, but that's a lot of code to maintain.

                  • rikarendsmp 1 hour ago

                    AI maintains it, and its developer tooling really. The main use case is hotloading for LLM's to reduce wait-for-result time and to allow applications other be hot-debugged. Pause on panic is one of its main features I use all the time.

                  • kennykartman 1 day ago

                    I knew that makepad devs were focused on build times, but didn't imagine this much!

                    • rikarendsmp 1 hour ago

                      Indeed but I could only do this in the age of AI. Before a project like this was just out of reach.

                    • ridiculous_fish 4 hours ago

                      This is preposterously ambitious - a complete Rust re-implementation. Looks like it's mostly claude?

                      • pcwalton 3 hours ago

                        Yeah, this is pretty much a textbook example of what AI agents make possible these days: things that are ridiculously ambitious, but aren't conceptually very difficult (or, at least, are conceptually well-trodden ground). Things like emulators, language runtimes, platform reimplementations like Darling, etc.

                        JITting Rust isn't conceptually very hard: you just take rustc and make everything dynamic instead of static. The only thing that was stopping it before was the sheer amount of effort. Well, now we have a way to reduce that effort.

                        • rikarendsmp 1 hour ago

                          Yea it's claude+codex over the course of a month. It definitely isn't a one shot.

                        • tontinton 5 hours ago

                          The world really needs something like this, but why such a slop UI website.

                          Just tell Opus 5.5 to "redesign the UI to not look like AI slop, design it like a human expert designer would" at bare minimum.

                          • rikarendsmp 1 hour ago

                            Its only prompt is 'make a flashy website for this project'. I think it's fine who reads websites anymore anyway. Readme.md for GitHub is the main thing.

                            • hn_submit 2 hours ago

                              The code is slop and the website too.

                              • poly2it 3 hours ago

                                Perhaps a cynical take, but I feel sloppy content advertised seriously is enabling a transparent form of cross-domain self-selection which can be interesting to observe from the outside.

                              • baq 3 hours ago

                                Common Lisp lurks in the shadows, watching its own reinvention comfortably, yet another time

                                • Surac 4 hours ago

                                  moving errors from compile time to runtime is good?

                                  • andix 3 hours ago

                                    For quick iterations it's perfectly fine. Change something, see if it works. If it doesn't keep changing until it works.

                                    In runtimes that provide quick dev loops some developers have continiously running unit testing sessions. They just fire off every few seconds and give intimidate feedback.

                                    • jtwaleson 4 hours ago

                                      For some use cases, like speeding up local development, it's an excellent trade off.

                                      • rikarendsmp 1 hour ago

                                        It's a technology to improve iteration time with agents, or humans for live coding but nobody really writes code anymore so.