feat: allow using ia_solve without Nemo

src/solver/ia_main.jl

@@ -15,7 +15,19 @@ function isolate(lhs, var; warns=true, conditions=[], complex_roots = true, peri
             roots = []
             new_var = gensym()
             new_var = (@variables $new_var)[1]
-            lhs_roots = solve_univar(lhs - new_var, var)
+            if Base.get_extension(Symbolics, :SymbolicsNemoExt) !== nothing
+                lhs_roots = solve_univar(lhs - new_var, var)
+            else
+                a, b, islin = linear_expansion(lhs - new_var, var)
+                if islin
+                    lhs_roots = [-b / a]
+                else
+                    lhs_roots = [RootsOf(lhs - new_var, var)]
+                    if warns
+                        @warn "Nemo is required to properly solve this expression. Execute `using Nemo` to enable this functionality."
+                    end
+                end
+            end
 
             for i in eachindex(lhs_roots)
                 for j in eachindex(rhs)

test/solver.jl

@@ -1,5 +1,15 @@
 using Symbolics
 import Symbolics: ssqrt, slog, scbrt, symbolic_solve, ia_solve, postprocess_root
+
+@testset "ia_solve without Nemo" begin
+    @test Base.get_extension(Symbolics, :SymbolicsNemoExt) === nothing
+    @variables x
+    roots = ia_solve(log(2 + x), x)
+    @test substitute(roots[1], Dict()) == -1.0
+    roots = @test_warn ["Nemo", "required"] ia_solve(log(2 + x^2), x)
+    @test operation(roots[1]) == Symbolics.RootsOf
+end
+
 using Groebner, Nemo
 E = Base.MathConstants.e