Pdb.zip_chains: def of bend-prot@0.1.0.0
Import: import bend-prot@0.1.0.0/pdb.bend as Pdb
Lines 396-407 of bend-prot@0.1.0.0/pdb.bend: https://jend.leeeet.dev/read.txt?path=bend-prot@0.1.0.0/pdb.bend&start_line=396&end_line=407

import Base
import bend-prot@0.1.0.0/protein.bend as P

# Zip the parallel chain/residue lists back into pairs (aligned by
# construction; extra elements on either side are dropped).
def zip_chains(cs: List<&2, U32>, rs: List<&2, P.Residue>) -> List<&1, U32 & P.Residue>:
  match cs rs:
    case Nil{} Nil{}:
      Nil{}
    case Nil{} _ <> _:
      Nil{}
    case _ <> _ Nil{}:
      Nil{}
    case c <> ct r <> rt:
      (c, r) <> zip_chains(ct, rt)

Uses (5):
  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=Sigma
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=bend-prot@0.1.0.0/protein.bend&name=Residue