Notch.file.if: def of bend-kit-notch@0.4.0.0
Import: import bend-kit-notch@0.4.0.0/notch.bend as Notch
Lines 258-268 of bend-kit-notch@0.4.0.0/notch.bend: https://jend.leeeet.dev/read.txt?path=bend-kit-notch@0.4.0.0/notch.bend&start_line=258&end_line=268

import Base

# Write a stamped line and newline to a File; the returned handle must be kept or closed.
# Below the logger's level, returns the same handle and Done without a clock read or write.
def file.if(on: Bool, h: File, lg: Logger, lvl: Level, msg: String,
  fs: List<&2, Field>) -> IO(File & Result<&1, &1, U32 & String, Unit>):
  match on:
    case True{}:
      do IO<File & Result<&1, &1, U32 & String, Unit>>:
        s : String <- stamp(lg, lvl, msg, fs)
        File.write(h, s ++ "\n")
    case False{}:
      IO.pure(File & Result<&1, &1, U32 & String, Unit>, (h, Done{Unit{}}))

Uses (18):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=File
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=File.write
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=IO
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=IO.bind
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=IO.pure
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Pair
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Result
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Sigma
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String.append
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Unit
  https://jend.leeeet.dev/definition.txt?path=bend-kit-notch@0.4.0.0/notch.bend&name=Field
  https://jend.leeeet.dev/definition.txt?path=bend-kit-notch@0.4.0.0/notch.bend&name=Level
  https://jend.leeeet.dev/definition.txt?path=bend-kit-notch@0.4.0.0/notch.bend&name=Logger
  https://jend.leeeet.dev/definition.txt?path=bend-kit-notch@0.4.0.0/notch.bend&name=stamp