Frame.decode.lead: def of bolt@1.27.0.0
Import: import bolt@1.27.0.0/src/lsp/frame.bend as Frame
Lines 15-27 of bolt@1.27.0.0/src/lsp/frame.bend: https://jend.leeeet.dev/read.txt?path=bolt@1.27.0.0/src/lsp/frame.bend&start_line=15&end_line=27

import Base

# a lead byte, by its high nibble; a stray continuation byte stands for itself
def decode.lead(hi: U32, +bb: U32, out: List<&2, Char>) -> Dec:
  match hi:
    case 12:
      Dec{1n, (bb .&. 31 : U32), out}
    case 13:
      Dec{1n, (bb .&. 31 : U32), out}
    case 14:
      Dec{2n, (bb .&. 15 : U32), out}
    case 15:
      Dec{3n, (bb .&. 7 : U32), out}
    case other:
      Dec{0n, 0, Char.from_u32(bb) <> out}

Uses (9):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Char
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Char.from_u32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.and
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Word.Con
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Word.Nil
  https://jend.leeeet.dev/definition.txt?path=bolt@1.27.0.0/src/lsp/frame.bend&name=Dec