Curve.first: def of bend-collections@1.0.0.0
Import: import bend-collections@1.0.0.0/spec/crypto/secp256k1/curve.bend as Curve
Lines 221-225 of bend-collections@1.0.0.0/spec/crypto/secp256k1/curve.bend: https://jend.leeeet.dev/read.txt?path=bend-collections@1.0.0.0/spec/crypto/secp256k1/curve.bend&start_line=221&end_line=225

import Base

def first(n: Nat, bs: List<&2, U32>) -> List<&2, U32>:
  match n bs:
    case 0n _: Nil{}
    case 1n+k Nil{}: Nil{}
    case 1n+k b <> t: b <> first(k, t)

Uses (3):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32