Schnorr.sign_if: def of bend-collections-laws-crypto@1.0.0.0
Import: import bend-collections-laws-crypto@1.0.0.0/spec/crypto/secp256k1/schnorr.bend as Schnorr
Lines 120-125 of bend-collections-laws-crypto@1.0.0.0/spec/crypto/secp256k1/schnorr.bend: https://jend.leeeet.dev/read.txt?path=bend-collections-laws-crypto@1.0.0.0/spec/crypto/secp256k1/schnorr.bend&start_line=120&end_line=125

import Base

# sig = bytes(R) || bytes((k + e d) mod n); if Verify(bytes(P), m, sig)
# fails, abort
def sign_if(+sig: List<&2, U32>, ok: Bool) -> Maybe<&2, List<&2, U32>>:
  match ok:
    case True{}: Some{sig}
    case False{}: None{}

Uses (4):
  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=U32