Scan.stale.go: def of yaml-for-bend@0.1.1.0
Import: import yaml-for-bend@0.1.1.0/scan.bend as Scan
Lines 540-554 of yaml-for-bend@0.1.1.0/scan.bend: https://jend.leeeet.dev/read.txt?path=yaml-for-bend@0.1.1.0/scan.bend&start_line=540&end_line=554

import Base
import yaml-for-bend@0.1.1.0/token.bend as T

# Keys left behind are no longer possible. Keys go stale oldest first, so
# a level whose oldest possible key is still fresh has nothing stale at or
# below it, and the search stops there.
def stale.go(keys: List<&2, SKey>, +at: T.Mark) -> Result<&2, &2, T.Error, List<&2, SKey>>:
  match keys:
    case Nil{}:
      Done{[]}
    case Con{k, +rest}:
      match k:
        case SKey{+possible, +required, +number, +kat, +tab, +low}:
          +old = Bool.and(possible, is_stale(kat, at))
          when(Result<&2, &2, T.Error, List<&2, SKey>>, Bool.not(low.stale(low, at)), u => Done{SKey{possible, required, number, kat, tab, low} <> rest},
            u => when(Result<&2, &2, T.Error, List<&2, SKey>>, Bool.and(old, required),
              u => Fail{T.Error{"could not find expected ':' while scanning a simple key", kat, T.Syntax{}}},
              u => stale.cons(Bool.and(possible, Bool.not(old)), required, number, kat, tab, stale.go(rest, at))))

Uses (12):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.and
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.not
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Result
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/scan.bend&name=SKey
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/scan.bend&name=is_stale
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/scan.bend&name=low.stale
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/scan.bend&name=stale.cons
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/scan.bend&name=when
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/token.bend&name=Cause
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/token.bend&name=Error
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/token.bend&name=Mark