Export independent_variables, states, parameters, fix tests

Author: AayushSabharwal

src/ModelingToolkit.jl

@@ -35,6 +35,8 @@ RuntimeGeneratedFunctions.init(@__MODULE__)
 using RecursiveArrayTools
 
 import SymbolicIndexingInterface
+import SymbolicIndexingInterface: independent_variables, states, parameters
+export independent_variables, states, parameters
 import SymbolicUtils
 import SymbolicUtils: istree, arguments, operation, similarterm, promote_symtype,
                       Symbolic, Term, Add, Mul, Pow, Sym, FnType,

test/odesystem.jl

@@ -930,9 +930,9 @@ let
     # TODO: maybe do not emit x_t
     sys4s = structural_simplify(sys4)
     prob = ODAEProblem(sys4s, [x => 1.0, D(x) => 1.0], (0, 1.0))
-    @test string.(prob.f.syms) == ["x(t)", "xˍt(t)"]
-    @test string.(prob.f.paramsyms) == ["pp"]
-    @test string(prob.f.indepsym) == "t"
+    @test string.(states(prob.f.sys)) == ["x(t)", "xˍt(t)"]
+    @test string.(parameters(prob.f.sys)) == ["pp"]
+    @test string.(independent_variables(prob.f.sys)) == ["t"]
 end
 
 let