Nimble RFCs for Araq

README.md

nim.cfg based interop

Nimble requirements

• Add a new command called nimble usecfg
  • Creates/updates nimbledeps.cfg
  • Adds --path entries for all dependencies
  • Includes --clearNimblePath as well to remove any scanned packages already added
  • Uses @include in nim.cfg to load nimbledeps.cfg if it exists
• Nimble should detect if project is in usecfg mode
  • Check if nimbledeps.cfg exists and is being @include'ed
• Nimble functions like today if not in usecfg mode
  • User needs to opt in and use nimble usecfg once for project to get into this mode
• When in usecfg mode
  • Commands like nimble c, nimble build, nimble docs should execute usecfg before calling Nim
  • Above commands should no longer pass --path via CLI arguments to Nim
  • When saving to nimbledeps.cfg, Nimble should optimize if file really needs to be updated or if it is up to date
• Backwards compatibility
  • Need to handle packages with existing nim.cfg without breakage - Need to handle cases where nim.cfg already has some --path or --nimblePath instances added by user
  • Need to ensure compatibility with existing config.nims
• This change should work with standard ~/.nimble as well as a custom --nimbleDir - Need to evaluate impacts on other Nim tools that could potentially update nim.cfg or hard-code paths

Nim requirements

• Nim should support $nimbleDir substitution in --path calls to enable relative paths - DONE
  • $nimblePath and $nimbleDir both are supported
  • Handled differently than other $ substitutions since it is one to many
  • Every $nimbleDir added to Nim will be added to searchPaths
    • If $nimbleDir = ["$home/.nimble/pkgs", "$projectpath/nimbledeps/pkgs"]
    • --path:"$nimbleDir/pkg-0.1.0" will searchPaths.add(["$projectpath/nimbledeps/pkgs/pkg-0.1.0", "$home/.nimble/pkgs/pkg-0.1.0"])
  • nim-lang/Nim#12750
• Nim should support @include directive to nim.cfg that allows including a separate file
  • Syntax @include "path/to/file" or @include varName
  • Path should be processed with pathSubs() to allow $projectpath style substitutions
  • If path specified does not exist, Nim will fail
  • Behavior if older Nim loads @include - what happens
• Nim should support @if fileExists("path/to/file) or @if fileExists(varName)
  • Allow optional @include of separate files - @if fileExists(fName): @include fName @end
  • Behavior if older Nim loads @if fileExists - what happens

nimble develop --recurse

Recursive develop - the ability to actively develop a project and all its dependencies locally.

Nimble requirements

• Need a new nimble develop --recurse flag that sets all dependencies in a local nimble develop mode
  • Main project is checked out with nimble develop
  • Each dependency is also checked out with nimble develop mode
  • Each dependency is stored in a project local nimbledeps directory and not the global $nimbleDir
• --recurse should work with usecfg as well as standard Nimble behavior
  • usecfg works well for --recurse but forcing it would result in nim.cfg changes that user may not want to check in
  • Standard Nimble behavior can use --nimbleDir but that too will need nim.cfg changes
  • Unclear at this point how standard Nimble behavior can coexist with --recurse - open to ideas

Updated editcfg to modecfg after discussion with @Araq since it suggests a change in Nimble behavior beyond a single command.

Added nimble develop --recurse RFC as well into this same gist.

One concern with modecfg - we will be passing --noNimblePath so that Nim will no longer search $nimbleDir for dependencies itself but simply use the --path packages specified.

However, modecfg does require relative paths and we have proposed $nimbleDir substitution in --path entries that Nim will handle. So this means that Nim won't search $nimbleDir itself but will still need to be aware of $nimbleDir when --noNimblePath is specified. i.e. on Posix, default to ~/.nimble or %APPDATA%\.nimble on Windows.

I think this should be okay but just wanted to highlight it.

I think this should be okay

I completely agree.

Added $nimbleDir substitution implementation details in Nim and PR link

This is looking good, although I might raise things in your PRs, so don't take this as a promise that I won't find something that I want changed.

One small thing I will do now is bikeshed :) Can we call this nimble usecfg instead?

@dom96 - absolutely - expected and welcome.

I'll go with usecfg.

Updates:

• Introduce @include and @if fileExists Nim features
• Update usecfg to use @include instead
• Replace modecfg with usecfg

Is this still being worked on?