Singular

LIB "olga.lib";
ring r = QQ[x,y,Dx,Dy];
def R = Weyl();
setring R;
fracStatus([1,0,0,0], 42, list(1));
==> [1]:
==>    0
==> [2]:
==>    invalid localization in fraction: gen(1)
==>       invalid localization: type is 42, valid types are:
==> 0 for a monoidal localization
==> 1 for a geometric localization
==> 2 for a rational localization
list L = x;
fracStatus([0,7,x,0], 0, L);
==> [1]:
==>    0
==> [2]:
==>    vector is not a valid fraction: no denominator specified in x*gen(3)+7\
   *gen(2)
fracStatus([Dx,Dy,0,0], 0, L);
==> [1]:
==>    0
==> [2]:
==>    the left denominator Dx of fraction Dx*gen(1)+Dy*gen(2) is not in the \
   denominator set of type 0 given by x
fracStatus([0,0,Dx,Dy], 0, L);
==> [1]:
==>    0
==> [2]:
==>    the right denominator Dy of fraction Dx*gen(3)+Dy*gen(4) is not in the\
    denominator set of type 0 given by x
fracStatus([x,Dx,Dy,x], 0, L);
==> [1]:
==>    0
==> [2]:
==>    left and right representation are not equal in:x*gen(4)+x*gen(1)+Dx*ge\
   n(2)+Dy*gen(3)
fracStatus([x,Dx,x*Dx+2,x^2], 0, L);
==> [1]:
==>    1
==> [2]:
==>    valid fraction