/* j/3/tape.c
**
** This file is in the public domain.
*/
#include "all.h"
#include "../pit.h"

/* functions
*/
  static u2_noun                                                  //  transfer
  _norm(u2_wire wir_r,
        u2_noun a)                                                //  retain
  {
    if ( u2_no == u2du(a) ) {
      return u2_nul;
    } else {
      return u2nc(((u2_yes == u2du(u2h(a))) ? u2_nul : u2k(u2h(a))),
                  _norm(wir_r, u2t(a)));
    }
  }
  
  static u2_bean
  _good(u2_wire wir_r,
        u2_noun a)                                                //  retain
  {
    while ( 1 ) {
      if ( u2_nul == a ) {
        return u2_yes;
      }
      if ( u2_no == u2ud(u2h(a)) ) {
        return u2_no;
      }
      a = u2t(a);
    }
  }

  u2_noun                                                         //  transfer
  j2_mby(PtM, tape)(u2_wire wir_r, 
                    u2_noun a)                                    //  retain
  {
    if ( u2_yes == _good(wir_r, a) ) {
      fprintf(stderr, "good!\r\n");
      return u2k(a);
    } else {
      return _norm(wir_r, a);
    } 
  }
  u2_noun                                                         //  transfer
  j2_mb(PtM, tape)(u2_wire wir_r, 
                   u2_noun cor)                                    //  retain
  {
    u2_noun a;

    if ( (u2_none == (a = u2_frag(u2_cv_sam, cor))) ) {
      return u2_bl_bail(wir_r, c3__fail);
    } else {
      return j2_mby(PtM, tape)(wir_r, a);
    }
  }

/* structures
*/
  u2_ho_jet 
  j2_mbj(PtM, tape)[] = {
    { ".2", c3__hevy, j2_mb(PtM, tape), Tier3, u2_none, u2_none },
    { }
  };