Scan.unprintable: def of yaml-for-bend@0.1.1.0
Import: import yaml-for-bend@0.1.1.0/scan.bend as Scan
Lines 1509-1516 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=1509&end_line=1516

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

# Where the first character YAML doesn't allow is (a control character, a
# surrogate), if there is one.
def unprintable(s: String, +at: T.Mark) -> Maybe<&2, T.Mark>:
  match s:
    case SNil{}:
      None{}
    case SCon{+c, t}:
      when(Maybe<&2, T.Mark>, is_printable(c), u => unprintable(t, past(at, c)), u => Some{at})

Uses (6):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Maybe
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/scan.bend&name=is_printable
  https://jend.leeeet.dev/definition.txt?path=yaml-for-bend@0.1.1.0/scan.bend&name=past
  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=Mark