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13032 :: Road to Nimble 1.0.0 Redesign (Inspired by Atlas)

• jmgomez (orginal) [2025-05-28T13:06:38+02:00] view original

  The new nimble 1.0.0 will feature a SAT-based design with a brand-new greenfield code path, reducing complexity and improving maintainability. local dependencies resolution will be the new default.

  • No Nim required initially – resolves Nim version from compilation.nim, no VM fallback for Nim itself.
  • Centralized, upfront resolution – dependencies are solved globally at the start, unlike the legacy greedy approach.
  • Single-pass by default – declarative parser handles everything; fallback to the VM parser (with the resolved Nim) only for tricky packages or when it detects a require inside a control flow statement.
  • Local dependencies by default – ensures predictable behavior and avoids global pollution.
  • Fallback ensures compatibility – guarantees recompatibility with existing projects, unlike Atlas.
  • Atlas as inspiration and testbed – Atlas helped shape and validate the new system.
  • Key advantage over Atlas – Atlas can’t detect failures and retry; Nimble’s fallback to the VM parser prevents resolution failures.
  • Paves the road for a new choosenim alternative – laying the foundation for future improvements in Nim version management.
  • Improved speed – declarative parser is faster than the VM parser as it is Nim selection. In some initial tests and scenarios it was 200 times faster (not consistent though). There are also plans to paralleize git fetching and to make a better use of the cache.

  Current state at the time of writing:

  • Still global
  • Supported action install, build, setup, run.
  • To activate the new design, use nimble {action} --parser:declarative (only in sources version, it will be the default in 1.0.0)

  https://github.com/nim-lang/nimble/pull/1396

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• didlybom (orginal) [2025-05-28T15:31:33+02:00] view original

  laying the foundation for future improvements in Nim version management.

  I assume this means that nimble will be the only tool you will need to install since it will be able to download, install and select nim versions without having to compile nim itself?

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• jmgomez (orginal) [2025-05-28T16:05:55+02:00] view original

  Correct. Although it will require at least one compilation depending on the platform and Nim version.

  Command should be something in these lines: nimble install nim{constraint} when outside of a project dir.

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• ITwrx (orginal) [2025-05-29T01:00:20+02:00] view original

  It's great that this is being worked on. I hope it will compile without issue on alpine and other Ganoo+Linoxes. I've had a fair a mount of friction with nimble, choosenim, and nim packages for alpine. If i wasn't such a fanatic i probably would have given up. :)

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