Target.utf.lead: def of bend-kit-router@0.2.0.0
Import: import bend-kit-router@0.2.0.0/target.bend as Target
Lines 16-26 of bend-kit-router@0.2.0.0/target.bend: https://jend.leeeet.dev/read.txt?path=bend-kit-router@0.2.0.0/target.bend&start_line=16&end_line=26

import Base

def utf.lead(+c: U32, out: String, ascii: Bool) -> Maybe<&2, Utf>:
  match ascii:
    case True{}:
      Some{Utf{0, 128, 191, 0, SCon{Chr{c}, out}}}
    case False{}:
      +valid = between(c, 194, 244)
      +need = Bool.pick(U32, U32.is_lt(c, 224), 1, Bool.pick(U32, U32.is_lt(c, 240), 2, 3))
      +lo = Bool.pick(U32, U32.is_eq(c, 224), 160, Bool.pick(U32, U32.is_eq(c, 240), 144, 128))
      +hi = Bool.pick(U32, U32.is_eq(c, 237), 159, Bool.pick(U32, U32.is_eq(c, 244), 143, 191))
      mask = Bool.pick(U32, U32.is_eq(need, 1), 31, Bool.pick(U32, U32.is_eq(need, 2), 15, 7))
      Bool.pick(Maybe<&2, Utf>, valid, Some{Utf{need, lo, hi, (c .&. mask : U32), out}}, None{})

Uses (11):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.pick
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Char
  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=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=U32.is_eq
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.is_lt
  https://jend.leeeet.dev/definition.txt?path=bend-kit-router@0.2.0.0/target.bend&name=Utf
  https://jend.leeeet.dev/definition.txt?path=bend-kit-router@0.2.0.0/target.bend&name=between