[WIP, TODO] turn some include => import in system.nim

[timotheecour]

• refs Split system conceptually for doc purposes #10385
  followup on System cleanup, part 2 #13155 see System cleanup, part 2 #13155 (comment)

what changed:

• turned to import:
  system/arithmetics
  system/exceptions
  system/setops
  system/iterators_1
  system/arithmetics

• new import:
  system/privatedefs

• kept as include:
  system/comparisons

same could be done for remaining includes in future PR's

note

I had to keep the following include's:

• system/basic_types
  because of: Error: system module needs: int
• system/gc_interface
  because they define public procs but no implementation
  maybe this could be dealt with using importc/exportc ; but should be in future PR's
• system/memalloc
  ditto

note

• also related: {.nosystem.} (see Split system conceptually for doc purposes #10385 (comment)) which would allow a user to skip importing all of what system imports and instead choose what he wants
• import foo {.privateImport.} ([superseded] import foo {.all.} #11865) would simplify a number of things, eg it'd allow to put back StackTraceEntry and Exception inside exceptions.nim; right now i had to re-move it inside system.nim because of some private fields (up, trace, raiseId); with [superseded] import foo {.all.} #11865 you'd instead have:

# in system/excpt.nim:
{.push experimental: "allowPrivateImport".}
import system/exceptions {.privateImport.} # => gives access to private fields Exception.trace etc just inside this module

• likewise, it'd allow to make system/comparisons an import, right now it'd fail for ./bin/nim c --newruntime -d:useMalloc --listfullpaths tests/destructor/tnewruntime_strutils.nim because NimSeqV2.p is private
  (plus some mysterious change of stacktrace, see ./bin/nim c -r testament/testament --nim:bin/nim r tests/enum/tenummix.nim, which I don't understand)

[Araq]

Sorry, I know it's WIP, but I really don't like it. In practice include is much easier for me to understand, esp when things go wrong inside the compiler.

[narimiran]

Sorry, I know it's WIP, but I really don't like it. In practice include is much easier for me to understand, esp when things go wrong inside the compiler.

This should be the reason enough to close/reject this. Let us focus on more important stuff.