ipints()
[Ip interpreter subroutine.]
     const ASIZE=50;
     safe r,i^,i,j,C.
     global I[ASIZE],V[ASIZE],V,r,i^,i,j,C.
(1) [Factor (F command).]
     if C=='F' then
     {  if r>=1 then ipfac(r,I[i];s,c,L) else
     { B=iabsf(I[i]);  ilwrit(ifact(B)); emptob; return };
     n=length(L); if i^+n>ASIZE then { u#=OUNIT;  OUNIT=6;
     print "item array full; automatic cycling occurring";
     i^=0;  OUNIT=u# };
     clout("sign="); awrite(s);
     clout("   integer content=");
     iwrite(c); emptob; while L ne () do
     { adv(L;M,L); i^=i^+1;
     adv2(M;e1,I[i^],M); 
     clout ("multiplicity = "); awrite(e1); 
     clout ("     factor = I"); 
     cwrite('(');  awrite(i^);  cwrite(')');
     emptob;
     ipsw(I[i^],V[i]);  V[i^]=V[i] };
     return  };
(2)  [Product (* command).]
     if C=='*' then
     {  if i^==ASIZE then { OUNIT=6;  print "item array full";
     return };  i^=i^+1;
     I[i^]=ipprod(r,I[i],I[j]); V[i^]=V[i];
     clout("product = I"); cwrite('('); awrite(i^);
     cwrite(')'); emptob;
     ipsw(I[i^],V[i^]);  return  };
(3) [Sum (+ command).]
     if C=='+' then
     {  if i^==ASIZE then { OUNIT=6;  print "item array full";
     return };  i^=i^+1;
     I[i^]=ipsum(r,I[i],I[j]); V[i^]=V[i];
     clout("sum = I"); cwrite('('); awrite(i^);
     cwrite(')'); emptob;
     ipsw(I[i^],V[i^]);  return  };
(4) [Difference (- command).]
     if C=='-' then
     {  if i^==ASIZE then { OUNIT=6;  print "item array full";
     return };  i^=i^+1;
     I[i^]=ipdif(r,I[i],I[j]); V[i^]=V[i];
     clout("difference = I"); cwrite('('); awrite(i^);
     cwrite(')'); emptob;
     ipsw(I[i^],V[i^]);  return  };
(5) [GCD (G command).]
     if C=='G' then
     {  if i^==ASIZE then { OUNIT=6;  print "item array full";
     return };  i^=i^+1;
     IPGCDC(r,I[i],I[j];I[i^],c##,d##); V[i^]=V[i];
     clout("gcd = I"); cwrite('('); awrite(i^);
     cwrite(')'); emptob;
     ipsw(I[i^],V[i^]);  return  }..