Merge pull request #900 from pepijndevos/varscope

Implement variable scope

Author: ChrisRackauckas

src/ModelingToolkit.jl

@@ -158,6 +158,7 @@ export Differential, expand_derivatives, @derivatives
 export IntervalDomain, ProductDomain, ⊗, CircleDomain
 export Equation, ConstrainedEquation
 export Term, Sym
+export SymScope, LocalScope, ParentScope, GlobalScope
 export independent_variable, states, parameters, equations, controls, observed, structure
 export structural_simplify
 

src/systems/abstractsystem.jl

@@ -226,22 +226,22 @@ function Base.getproperty(sys::AbstractSystem, name::Symbol; namespace=true)
     i = findfirst(x->getname(x) == name, sts)
 
     if i !== nothing
-        return namespace ? rename(sts[i],renamespace(sysname,name)) : sts[i]
+        return namespace ? renamespace(sysname,sts[i]) : sts[i]
     end
 
     if has_ps(sys)
         ps = get_ps(sys)
         i = findfirst(x->getname(x) == name,ps)
         if i !== nothing
-            return namespace ? rename(ps[i],renamespace(sysname,name)) : ps[i]
+            return namespace ? renamespace(sysname,ps[i]) : ps[i]
         end
     end
 
     if has_observed(sys)
         obs = get_observed(sys)
         i = findfirst(x->getname(x.lhs)==name,obs)
         if i !== nothing
-            return namespace ? rename(obs[i].lhs,renamespace(sysname,name)) : obs[i]
+            return namespace ? renamespace(sysname,obs[i]) : obs[i]
         end
     end
 
@@ -268,11 +268,32 @@ function Base.setproperty!(sys::AbstractSystem, prop::Symbol, val)
     end
 end
 
+abstract type SymScope end
+
+struct LocalScope <: SymScope end
+LocalScope(sym::Union{Num, Sym}) = setmetadata(sym, SymScope, LocalScope())
+
+struct ParentScope <: SymScope
+    parent::SymScope
+end
+ParentScope(sym::Union{Num, Sym}) = setmetadata(sym, SymScope, ParentScope(getmetadata(value(sym), SymScope, LocalScope())))
+
+struct GlobalScope <: SymScope end
+GlobalScope(sym::Union{Num, Sym}) = setmetadata(sym, SymScope, GlobalScope())
+
 function renamespace(namespace, x)
     if x isa Num
         renamespace(namespace, value(x))
     elseif x isa Symbolic
-        rename(x, renamespace(namespace, getname(x)))
+        let scope = getmetadata(x, SymScope, LocalScope())
+            if scope isa LocalScope
+                rename(x, renamespace(namespace, getname(x)))
+            elseif scope isa ParentScope
+                setmetadata(x, SymScope, scope.parent)
+            else # GlobalScope
+                x
+            end
+        end
     else
         Symbol(namespace,:₊,x)
     end
@@ -300,7 +321,7 @@ function namespace_equation(eq::Equation,name,iv)
 end
 
 function namespace_expr(O::Sym,name,iv)
-    isequal(O, iv) ? O : rename(O,renamespace(name,nameof(O)))
+    isequal(O, iv) ? O : renamespace(name,O)
 end
 
 _symparam(s::Symbolic{T}) where {T} = T
@@ -309,7 +330,7 @@ function namespace_expr(O,name,iv) where {T}
     if istree(O)
         renamed = map(a->namespace_expr(a,name,iv), arguments(O))
         if operation(O) isa Sym
-            renamed_op = rename(O,renamespace(name, getname(O)))
+            rename(O,getname(renamespace(name, O)))
         else
             similarterm(O,operation(O),renamed)
         end

test/runtests.jl

@@ -1,5 +1,6 @@
 using SafeTestsets, Test
 
+@safetestset "Varialbe scope tests" begin include("variable_scope.jl") end
 @safetestset "Symbolic parameters test" begin include("symbolic_parameters.jl") end
 @safetestset "Parsing Test" begin include("variable_parsing.jl") end
 @safetestset "Simplify Test" begin include("simplify.jl") end

test/variable_scope.jl

@@ -0,0 +1,35 @@
+using ModelingToolkit
+using Test
+
+@parameters t
+@variables a b(t) c d
+
+b = ParentScope(b)
+c = ParentScope(ParentScope(c))
+d = GlobalScope(d)
+
+renamed(nss, sym) = ModelingToolkit.getname(foldr(ModelingToolkit.renamespace, nss, init=sym))
+
+@test renamed([:foo :bar :baz], a) == :foo₊bar₊baz₊a
+@test renamed([:foo :bar :baz], b) == :foo₊bar₊b
+@test renamed([:foo :bar :baz], c) == :foo₊c
+@test renamed([:foo :bar :baz], d) == :d
+
+eqs = [
+    0 ~ a
+    0 ~ b
+    0 ~ c
+    0 ~ d
+]
+@named sub4 = NonlinearSystem(eqs, [a, b, c, d], [])
+@named sub3 = NonlinearSystem(eqs, [a, b, c, d], [])
+@named sub2 = NonlinearSystem([], [], [], systems=[sub3, sub4])
+@named sub1 = NonlinearSystem([], [], [], systems=[sub2])
+@named sys = NonlinearSystem([], [], [], systems=[sub1])
+
+names = ModelingToolkit.getname.(states(sys))
+@test :d in names
+@test :sub1₊c in names
+@test :sub1₊sub2₊b in names
+@test :sub1₊sub2₊sub3₊a in names
+@test :sub1₊sub2₊sub4₊a in names