Hkdf.expand_if: def of bend-collections@1.0.0.0
Import: import bend-collections@1.0.0.0/spec/crypto/hkdf.bend as Hkdf
Lines 41-47 of bend-collections@1.0.0.0/spec/crypto/hkdf.bend: https://jend.leeeet.dev/read.txt?path=bend-collections@1.0.0.0/spec/crypto/hkdf.bend&start_line=41&end_line=47

import Base

# Expand is defined for L <= 255*HashLen only.
def expand_if(+prk: List<&2, U32>, +info: List<&2, U32>, +len: Nat, ok: Bool) -> Maybe<&2, List<&2, U32>>:
  match ok:
    case True{}:
      Some{okm(prk, info, len)}
    case False{}:
      None{}

Uses (6):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  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=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=bend-collections@1.0.0.0/spec/crypto/hkdf.bend&name=okm