Merge pull request #489 from tthsqe12/FFconv

add missing FField conversions

src/number/n_transExt.jl

@@ -321,10 +321,16 @@ end
 
 promote_rule(C::Type{n_transExt}, ::Type{T}) where T <: Integer = n_transExt
 
+promote_rule(C::Type{n_transExt}, ::Type{T}) where T <: Rational = n_transExt
+
 promote_rule(C::Type{n_transExt}, ::Type{Nemo.fmpz}) = n_transExt
 
+promote_rule(C::Type{n_transExt}, ::Type{Nemo.fmpq}) = n_transExt
+
 promote_rule(C::Type{n_transExt}, ::Type{n_Z}) = n_transExt
 
+promote_rule(C::Type{n_transExt}, ::Type{n_Q}) = n_transExt
+
 ###############################################################################
 #
 #   Parent call functions
@@ -338,6 +344,17 @@ function (R::N_FField)(n::n_transExt)
    return n
 end
 
+function (F::Singular.N_FField)(x::gfp_elem)
+   if characteristic(F) != characteristic(parent(x))
+      throw(ArgumentError("wrong characteristic"))
+   end
+   return n_transExt(F, x.data)
+end
+
+function (F::Singular.N_FField)(x::Union{n_Q, Nemo.fmpq, Rational})
+   return F(numerator(x)) // F(denominator(x))
+end
+
 (R::N_FField)(n::libSingular.number_ptr) = n_transExt(R, n)
 
 ###############################################################################

test/number/n_transExt-test.jl

@@ -66,6 +66,14 @@ end
 
    @test deepcopy(F(2)) == F(2)
    @test n_transExt_to_spoly(x, parent_ring = R) == p
+
+   @test F(1//2) == F(3)
+   @test F(1//2) == 1//2
+   @test F(1//2) == big(1//2)
+   @test F(1//2) == QQ(1//2)
+   @test F(1//2) == Nemo.QQ(1//2)
+   @test F(Nemo.GF(5)(3)) == 1//2
+   @test_throws Exception F(Nemo.GF(7)(3))
 end
 
 @testset "n_transExt.unary_ops" begin