def sign_if

bend-collections@1.0.0.0 · spec/crypto/secp256k1/schnorr.bend:120

import Base

120# sig = bytes(R) || bytes((k + e d) mod n); if Verify(bytes(P), m, sig)
121# fails, abort
122def sign_if(+sig: List<&2, U32>, ok: Bool) -> Maybe<&2, List<&2, U32>>:
123  match ok:
124    case True{}: Some{sig}
125    case False{}: None{}