Function rSetHdl

Singular/ipshell.cc:5121–5179

from ring.cc

// from ring.cc
void rSetHdl(idhdl h)
{
  ring rg = NULL;
  if (h!=NULL)
  {
//   Print(" new ring:%s (l:%d)\n",IDID(h),IDLEV(h));
    rg = IDRING(h);
    if (rg==NULL) return; //id <>NULL, ring==NULL
    omCheckAddrSize((ADDRESS)h,sizeof(idrec));
    if (IDID(h))  // OB: ????
      omCheckAddr((ADDRESS)IDID(h));
    rTest(rg);
  }
  else return;

  // clean up history
  if (currRing!=NULL)
  {
    if(sLastPrinted.RingDependend())
    {
      sLastPrinted.CleanUp();
    }

    if (rg!=currRing)/*&&(currRing!=NULL)*/
    {
      if (rg->cf!=currRing->cf)
      {
        denominator_list dd=DENOMINATOR_LIST;
        if (DENOMINATOR_LIST!=NULL)
        {
          if (TEST_V_ALLWARN)
            Warn("deleting denom_list for ring change to %s",IDID(h));
          do
          {
            n_Delete(&(dd->n),currRing->cf);
            dd=dd->next;
            omFreeBinAddr(DENOMINATOR_LIST);
            DENOMINATOR_LIST=dd;
          } while(DENOMINATOR_LIST!=NULL);
        }
      }
    }
  }

  // test for valid "currRing":
  if ((rg!=NULL) && (rg->idroot==NULL))
  {
    ring old=rg;
    rg=rAssure_HasComp(rg);
    if (old!=rg)
    {
      rKill(old);
      IDRING(h)=rg;
    }
  }
   /*------------ change the global ring -----------------------*/
  rChangeCurrRing(rg);
  currRingHdl = h;