Blake2s.keep_if: def of bend-collections-laws-crypto@1.0.0.0
Import: import bend-collections-laws-crypto@1.0.0.0/spec/crypto/blake/blake2s.bend as Blake2s
Lines 129-133 of bend-collections-laws-crypto@1.0.0.0/spec/crypto/blake/blake2s.bend: https://jend.leeeet.dev/read.txt?path=bend-collections-laws-crypto@1.0.0.0/spec/crypto/blake/blake2s.bend&start_line=129&end_line=133

import Base

# Zero padding: the byte at message offset i survives only when i < length.
def keep_if(inside: Bool, b: U32) -> U32:
  match inside:
    case True{}: b
    case False{}: 0

Uses (2):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32