/* j/6/wrap.c
**
*/
#include "all.h"

  static u3_noun _cqfu_wrap(u3_noun, u3_noun, u3_noun);

  static u3_noun
  _wrap_fork(u3_noun van, u3_noun p_sut, u3_noun yoz)
  {
    if ( u3_nul == p_sut ) {
      return u3_nul;
    } 
    else {
      return u3nc(_cqfu_wrap(van, u3h(p_sut), yoz),
                  _wrap_fork(van, u3t(p_sut), yoz));
    }
  }

  static u3_noun
  _cqfu_wrap(u3_noun van,
             u3_noun sut,
             u3_noun yoz)
  {
    u3_noun p_sut, q_sut;

    if ( c3n == u3du(sut) )  {
      return u3m_error("wrap-type");
    }
    else switch ( u3h(sut) ) {
      default: return u3m_error("wrap-type");

      case c3__core: u3x_cell(u3t(sut), &p_sut, &q_sut);
      {
        u3_noun pq_sut, qq_sut, rq_sut;
        u3_noun ppq_sut, qpq_sut, rpq_sut;

        if ( c3n == u3r_trel(q_sut, &pq_sut, &qq_sut, &rq_sut) ) {
          return u3m_bail(c3__fail);
        }
        if ( c3n == u3r_trel(pq_sut, &ppq_sut, &qpq_sut, &rpq_sut) ) {
          return u3m_bail(c3__fail);
        }
        else if ( (c3__gold != rpq_sut) &&
                  (c3__lead != yoz) ) {
          return u3m_error("wrap-metal");
        }
        else {
          return u3nt(c3__core,
                      u3k(p_sut),
                      u3nt(u3nt(u3k(ppq_sut), u3k(qpq_sut), u3k(yoz)),
                           u3k(qq_sut),
                           u3k(rq_sut)));
        }
      }
      case c3__fork: p_sut = u3t(sut);
      {
        u3_noun yed = u3qdi_tap(p_sut);
        u3_noun ret = u3kf_fork(_wrap_fork(van, yed, yoz));

        u3z(yed);
        return ret;
      }
      case c3__hold:
      {
        u3_noun fop = u3qfu_repo(van, sut);
        u3_noun pro = _cqfu_wrap(van, fop, yoz);

        u3z(fop);
        return pro;
      }
    }
  }

/* boilerplate
*/
  u3_noun
  u3wfu_wrap(u3_noun cor)
  {
    u3_noun sut, yoz, van;

    if ( (c3n == u3r_mean(cor, u3x_sam, &yoz, u3x_con, &van, 0)) ||
         (u3_none == (sut = u3r_at(u3x_sam, van))) )
    {
      return u3m_bail(c3__fail);
    } else {
      return _cqfu_wrap(van, sut, yoz);
    }
  }

  u3_noun
  u3qfu_wrap(u3_noun van,
             u3_noun sut,
             u3_noun yoz)
  {
    return _cqfu_wrap(van, sut, yoz);
  }