create correct Singular coeffs with create_ring_from_singular_ring

deps/src/coeffs.cpp

@@ -236,6 +236,38 @@ void singular_define_coeffs(jlcxx::Module & Singular)
  return bool(nCoeff_is_algExt(n));
  });
 
+ Singular.method("nCoeff_is_Nemo_AnticNumberField", [](coeffs n) {
+ return n->type==n_Nemo_AnticNumberField;
+ });
+
+ Singular.method("nCoeff_is_Nemo_QQField", [](coeffs n) {
+ return n->type==n_Nemo_QQField;
+ });
+
+ Singular.method("nCoeff_is_Nemo_ZZRing", [](coeffs n) {
+ return n->type==n_Nemo_ZZRing;
+ });
+
+ Singular.method("nCoeff_is_Nemo_FqPolyRepField", [](coeffs n) {
+ return n->type==n_Nemo_FqPolyRepField;
+ });
+
+ Singular.method("nCoeff_is_Nemo_fqPolyRepField", [](coeffs n) {
+ return n->type==n_Nemo_fqPolyRepField;
+ });
+
+ Singular.method("nCoeff_is_Nemo_Field", [](coeffs n) {
+ return n->type==n_Nemo_Field;
+ });
+
+ Singular.method("nCoeff_is_Nemo_Ring", [](coeffs n) {
+ return n->type==n_Nemo_Ring;
+ });
+
+ Singular.method("nGetCoeffData", [](coeffs n) {
+ return n->data;
+ });
+
  /* make a copy of a coefficient domain (actually just increments a
  * reference count) */
  Singular.method("nCopyCoeff", &nCopyCoeff);

src/caller.jl

@@ -192,6 +192,12 @@ function create_ring_from_singular_ring(r::libSingular.ring_ptr)
  minpoly = F(libSingular.algExt_GetMinpoly(c, F.ptr))
  basering = N_AlgExtField(libSingular.nCopyCoeff(c), minpoly)
  T = n_algExt
+ elseif libSingular.nCoeff_is_Nemo_Field(c) || libSingular.nCoeff_is_Nemo_Ring(c)
+ cf = libSingular.nCopyCoeff(c)
+ data_ptr = libSingular.nGetCoeffData(cf)
+ R = unsafe_pointer_to_objref(data_ptr)
+ basering = CoefficientRing(R) # FIXME: should we set cache=false ?
+ T = elem_type(basering)
  else
  basering = N_UnknownSingularCoefficientRing(libSingular.nCopyCoeff(c))
  T = n_unknownsingularcoefficient

test/caller-test.jl

@@ -249,3 +249,10 @@ end
  @test Singular.libSingular.random() == 16807
  @test Singular.libSingular.random() == 282475249
 end
+
+@testset "Nemo coeffs" begin
+ F = Nemo.fraction_field(Nemo.polynomial_ring(Nemo.ZZ)[1])
+ R, x = Singular.polynomial_ring(F, [:x])
+ S = Singular.create_ring_from_singular_ring(Singular.libSingular.rCopy(R.ptr))
+ @test base_ring(R) == base_ring(S)
+end