def pick_ix

mylsm-lsm-store@0.6.0.1 · src/Sstable.bend:446

import Base
import mylsm-lsm-store@0.6.0.1/src/Keys.bend as Keys
import mylsm-lsm-store@0.6.0.1/src/MemTable.bend as MemTable

446# Block-scoped lookup. Checker constraints (proven by scratch experiments):
447# multi-scrutinee matches follow declaration order, and only Nat answers flow
448# through match arms — so selection returns an index, picked up by chunk_at_go.
449def pick_ix(bt: List<&2, String>, ct: List<&2, List<&2, MemTable.Entry>>, ix: Nat, +key: String, order: Cmp) -> Nat:
450  match bt ct order:
451    case _ _ GT{}:
452      Nat.sub(ix, 1n)
453    case Nil{} _ _:
454      ix
455    case _ Nil{} _:
456      ix
457    case Con{b2, bt2} Con{d2, ct2} LT{}:
458      pick_ix(bt2, ct2, Nat.add(ix, 1n), key, Keys.cmp(b2, key))
459    case Con{b2, bt2} Con{d2, ct2} EQ{}:
460      ix