fix import issues

Author: schillic

src/SpaceExParser.jl

@@ -6,20 +6,25 @@ export readsxmodel, writesxmodel
 Load dependencies
 =========================================#
 
-using HybridSystems, LazySets
 using DataStructures: OrderedDict
-import MathematicalSystems
-using MathematicalSystems: AbstractSystem, AbstractContinuousSystem,
-                           LinearContinuousSystem, LinearControlContinuousSystem,
+using EzXML: readxml, root, eachelement, nodename, nodecontent
+using HybridSystems: AbstractSwitching, AutonomousSwitching, GraphAutomaton,
+                     HybridSystem, add_transition!, assignment, guard, inputdim,
+                     inputset, nmodes, ntransitions, resetmap, source, statedim,
+                     stateset, target, transitions
+using LazySets: LazySets, AbstractHyperrectangle, HalfSpace, Hyperplane,
+                Intersection, LazySet, Singleton, dim, high, isuniversal, low
+using MathematicalSystems: MathematicalSystems, AbstractSystem,
+                           AbstractContinuousSystem, LinearContinuousSystem,
+                           LinearControlContinuousSystem,
                            AffineContinuousSystem,
                            AffineControlContinuousSystem,
                            ConstrainedLinearContinuousSystem,
                            ConstrainedLinearControlContinuousSystem,
                            ConstrainedLinearControlDiscreteSystem,
                            ConstrainedAffineContinuousSystem,
                            ConstrainedAffineControlContinuousSystem
-using EzXML: readxml, root, eachelement, nodename, nodecontent
-using SymEngine: Basic, subs
+using SymEngine: Basic, free_symbols, subs
 
 import Base: convert
 

src/parse.jl

@@ -1,4 +1,4 @@
-const _parse_s = Base.Meta.parse
+const _parse_s = Base.Meta.parse  # NOTE: this is an internal function
 const _parse_t = Base.parse
 
 """

src/symbolic.jl

@@ -208,16 +208,16 @@ end
 # ref_tuple is used for the error message
 function _add_invariants!(X, U, invariants, state_variables, input_variables, ref_tuple)
     for invi in invariants
-        if LazySets._ishyperplanar(invi)
+        if LazySets._ishyperplanar(invi)  # NOTE: this is an internal function
             set_type = Hyperplane{NUM}
-        elseif LazySets._ishalfspace(invi)
+        elseif LazySets._ishalfspace(invi)  # NOTE: this is an internal function
             set_type = HalfSpace{NUM}
         else
             loc_or_trans, id = ref_tuple
             error_msg_set(loc_or_trans, invi, id)
         end
 
-        vars = LazySets.free_symbols(invi, set_type)
+        vars = free_symbols(invi, set_type)
         got_state_invariant = all(si in state_variables for si in vars)
         got_input_invariant = all(si in input_variables for si in vars)
         if got_state_invariant