Survival.head_len: def of unified-nsga-iii@0.2.2.0
Import: import unified-nsga-iii@0.2.2.0/survival.bend as Survival
Lines 351-356 of unified-nsga-iii@0.2.2.0/survival.bend: https://jend.leeeet.dev/read.txt?path=unified-nsga-iii@0.2.2.0/survival.bend&start_line=351&end_line=356

import Base
import unified-nsga-iii@0.2.2.0/util.bend as Util

def head_len(fronts: List<&2, List<&2, Nat>>) -> Nat:
  match fronts:
    case Nil{}:
      0n
    case h <> t:
      Util.list_len(Nat, h)

Uses (3):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=unified-nsga-iii@0.2.2.0/util.bend&name=list_len