update with aayush code to handle flattened systems

Author: TorkelE

src/systems/abstractsystem.jl

@@ -1292,8 +1292,12 @@ $(TYPEDSIGNATURES)
 Get the unknown variables of the system `sys` and its subsystems.
 
 See also [`ModelingToolkit.get_unknowns`](@ref).
+
+Arguments:
+- `toplevel = false`: if set to true, do not return the continuous events of the subsystems.
 """
 function unknowns(sys::AbstractSystem; toplevel = false)
+    toplevel && (sys = recursive_get_parent(sys))
     sts = get_unknowns(sys)
     systems = get_systems(sys)
     nonunique_unknowns = if toplevel || isempty(systems)
@@ -1319,8 +1323,12 @@ $(TYPEDSIGNATURES)
 Get the parameters of the system `sys` and its subsystems.
 
 See also [`@parameters`](@ref) and [`ModelingToolkit.get_ps`](@ref).
+
+Arguments:
+- `toplevel = false`: if set to true, do not return the continuous events of the subsystems.
 """
 function parameters(sys::AbstractSystem; initial_parameters = false, toplevel = false)
+    toplevel && (sys = recursive_get_parent(sys))
     ps = get_ps(sys)
     if ps == SciMLBase.NullParameters()
         return []
@@ -1353,6 +1361,22 @@ function dependent_parameters(sys::AbstractSystem)
     return map(eq -> eq.lhs, parameter_dependencies(sys))
 end
 
+"""
+    recursive_get_parent(sys::AbstractSystem)
+
+Loops through parent systems to find the original parent system.
+
+Warning:
+- Curently only used (and tested) in the context of accessor functions (e.g. `parameters`),
+specifically in the context of the `toplevel` keyword argument.
+"""
+function recursive_get_parent(sys::AbstractSystem)
+    if ModelingToolkit.has_parent(sys) && (p = ModelingToolkit.get_parent(sys)) !== nothing
+        return recursive_get_parent(p)
+    end
+    return sys
+end
+
 """
 $(TYPEDSIGNATURES)
 Get the parameter dependencies of the system `sys` and its subsystems.
@@ -1491,6 +1515,7 @@ function controls(sys::AbstractSystem)
 end
 
 function observed(sys::AbstractSystem; toplevel = false)
+    toplevel && (sys = recursive_get_parent(sys))
     obs = get_observed(sys)
     toplevel && return obs
     systems = get_systems(sys)
@@ -1550,8 +1575,12 @@ It may include some abbreviations and aliases of observables.
 It is often the most useful way to inspect the equations of a system.
 
 See also [`full_equations`](@ref) and [`ModelingToolkit.get_eqs`](@ref).
+
+Arguments:
+- `toplevel = false`: if set to true, do not return the continuous events of the subsystems.
 """
 function equations(sys::AbstractSystem; toplevel = false)
+    toplevel && (sys = recursive_get_parent(sys))
     eqs = get_eqs(sys)
     systems = get_systems(sys)
     if toplevel || isempty(systems)

src/systems/callbacks.jl

@@ -320,14 +320,18 @@ function namespace_callback(cb::SymbolicContinuousCallback, s)::SymbolicContinuo
 end
 
 """
-    continuous_events(sys::AbstractSystem)::Vector{SymbolicContinuousCallback}
+    continuous_events(sys::AbstractSystem; toplevel = false)::Vector{SymbolicContinuousCallback}
 
 Returns a vector of all the `continuous_events` in an abstract system and its component subsystems.
 The `SymbolicContinuousCallback`s in the returned vector are structs with two fields: `eqs` and
 `affect` which correspond to the first and second elements of a `Pair` used to define an event, i.e.
 `eqs => affect`.
+
+Arguments:
+- `toplevel = false`: if set to true, do not return the continuous events of the subsystems.
 """
 function continuous_events(sys::AbstractSystem; toplevel = false)
+    toplevel && (sys = recursive_get_parent(sys))
     cbs = get_continuous_events(sys)
     filter(!isempty, cbs)
     toplevel && return cbs
@@ -476,14 +480,18 @@ SymbolicDiscreteCallbacks(cbs::Vector{<:SymbolicDiscreteCallback}) = cbs
 SymbolicDiscreteCallbacks(::Nothing) = SymbolicDiscreteCallback[]
 
 """
-    discrete_events(sys::AbstractSystem) :: Vector{SymbolicDiscreteCallback}
+    discrete_events(sys::AbstractSystem; toplevel = false) :: Vector{SymbolicDiscreteCallback}
 
 Returns a vector of all the `discrete_events` in an abstract system and its component subsystems.
 The `SymbolicDiscreteCallback`s in the returned vector are structs with two fields: `condition` and
 `affect` which correspond to the first and second elements of a `Pair` used to define an event, i.e.
 `condition => affect`.
+
+Arguments:
+- `toplevel = false`: if set to true, do not return the discrete events of the subsystems.
 """
 function discrete_events(sys::AbstractSystem; toplevel = false)
+    toplevel && (sys = recursive_get_parent(sys))
     cbs = get_discrete_events(sys)
     toplevel && return cbs
     systems = get_systems(sys)