Myers.trim_semiglobal: def of bend-edit-distance@0.2.2.0
Import: import bend-edit-distance@0.2.2.0/src/Myers.bend as Myers
Lines 465-480 of bend-edit-distance@0.2.2.0/src/Myers.bend: https://jend.leeeet.dev/read.txt?path=bend-edit-distance@0.2.2.0/src/Myers.bend&start_line=465&end_line=480

import Base
import bend-edit-distance@0.2.2.0/EdlibTypes.bend as E

# If the bottom score is >= k+32 every cell in that block is > k. Only
# trailing blocks are removed. HW always retains block zero: its free top
# boundary can seed a new alignment after an arbitrarily long target prefix.
def trim_semiglobal(entries: List<&2, BandEntry>, rest: List<&2, Peq>,
                    +mode: E.Mode, +index: Nat, +maximum: Nat) -> List<&2, BandEntry> & List<&2, Peq>:
  match entries mode:
    case Nil{} _:
      (Nil{}, rest)
    case BandEntry{profile, Block{pv, mv, +score}} <> tail E.HW{}:
      trim_last.join(BandEntry{profile, Block{pv, mv, score}},
        trim_semiglobal(tail, rest, mode, 1n+index, maximum),
        Bool.or(Nat.is_eq(index, 0n), Nat.is_lt(U32.to_nat(score), Nat.add(maximum, 32n))))
    case BandEntry{profile, Block{pv, mv, +score}} <> tail _:
      trim_last.join(BandEntry{profile, Block{pv, mv, score}},
        trim_semiglobal(tail, rest, mode, 1n+index, maximum),
        Nat.is_lt(U32.to_nat(score), Nat.add(maximum, 32n)))

Uses (14):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.or
  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=Base/base.bend&name=Nat.add
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.is_eq
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.is_lt
  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.to_nat
  https://jend.leeeet.dev/definition.txt?path=bend-edit-distance@0.2.2.0/EdlibTypes.bend&name=Mode
  https://jend.leeeet.dev/definition.txt?path=bend-edit-distance@0.2.2.0/src/Myers.bend&name=BandEntry
  https://jend.leeeet.dev/definition.txt?path=bend-edit-distance@0.2.2.0/src/Myers.bend&name=Block
  https://jend.leeeet.dev/definition.txt?path=bend-edit-distance@0.2.2.0/src/Myers.bend&name=Peq
  https://jend.leeeet.dev/definition.txt?path=bend-edit-distance@0.2.2.0/src/Myers.bend&name=trim_last.join