diff --git a/src/equations.jl b/src/equations.jl
index 9739f51de..58e5d4e4e 100644
--- a/src/equations.jl
+++ b/src/equations.jl
@@ -8,7 +8,9 @@ hide_lhs(_) = false
 struct Connection
     systems
 end
+Base.broadcastable(x::Connection) = Ref(x)
 Connection() = Connection(nothing)
+Base.hash(c::Connection, seed::UInt) = hash(c.systems, (0xc80093537bdc1311 % UInt) ⊻ seed)
 hide_lhs(_::Connection) = true
 
 function connect(sys1, sys2, syss...)
@@ -19,11 +21,13 @@ end
 
 function Base.show(io::IO, c::Connection)
     print(io, "connect(")
-    n = length(c.systems)
-    for (i, s) in enumerate(c.systems)
-        str = join(split(string(nameof(s)), NAMESPACE_SEPARATOR), '.')
-        print(io, str)
-        i != n && print(io, ", ")
+    if c.systems isa AbstractArray
+        n = length(c.systems)
+        for (i, s) in enumerate(c.systems)
+            str = join(split(string(nameof(s)), NAMESPACE_SEPARATOR), '.')
+            print(io, str)
+            i != n && print(io, ", ")
+        end
     end
     print(io, ")")
 end
@@ -34,6 +38,7 @@ end
 _nameof(s) = nameof(s)
 _nameof(s::Union{Int, Symbol}) = s
 abstract type StateMachineOperator end
+Base.broadcastable(x::StateMachineOperator) = Ref(x)
 hide_lhs(_::StateMachineOperator) = true
 struct InitialState <: StateMachineOperator
     s
diff --git a/src/struct.jl b/src/struct.jl
index c96706d30..f829c7a5f 100644
--- a/src/struct.jl
+++ b/src/struct.jl
@@ -72,6 +72,11 @@ struct Struct <: Real
     v::Vector{StructElement}
 end
 
+function Base.hash(x::Struct, seed::UInt)
+    h1 = hash(juliatype(x), seed)
+    h2 = foldr(hash, getelements(x), init = h1)
+    h2 ⊻ (0x0e39036b7de2101a % UInt)
+end
 
 """
     symstruct(T)