Regex.required: def of bend-kit-regex@0.8.0.0
Import: import bend-kit-regex@0.8.0.0/regex.bend as Regex
Lines 549-568 of bend-kit-regex@0.8.0.0/regex.bend: https://jend.leeeet.dev/read.txt?path=bend-kit-regex@0.8.0.0/regex.bend&start_line=549&end_line=568

import Base

def required(n: Node) -> Maybe<&2, U32>:
  match n:
    case NEmpty{}:
      None{}
    case NSet{False{}, Con{Rng{+lo, +hi}, Nil{}}}:
      Bool.pick(Maybe<&2, U32>, U32.is_eq(lo, hi) && U32.is_lt(lo, 128), Some{lo}, None{})
    case NSet{neg, items}:
      None{}
    case NAssert{k}:
      None{}
    case NCat{a, b}:
      required.right(required(b), required(a))
    case NAlt{a, b}:
      None{}
    case NPlus{g, a}:
      required(a)
    case NQuest{g, a}:
      None{}
    case NGroup{i, a}:
      required(a)

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.and
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.pick
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Maybe
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  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-regex@0.8.0.0/regex.bend&name=Item
  https://jend.leeeet.dev/definition.txt?path=bend-kit-regex@0.8.0.0/regex.bend&name=Node
  https://jend.leeeet.dev/definition.txt?path=bend-kit-regex@0.8.0.0/regex.bend&name=required.right