Better support for multi-adic operators

Author: BenChung

src/clock.jl

@@ -101,6 +101,7 @@ function is_discrete_domain(x)
 end
 
 sampletime(c) = Moshi.Match.@match c begin
+    x::SciMLBase.AbstractClock => nothing
     PeriodicClock(dt) => dt
     _ => nothing
 end

src/discretedomain.jl

@@ -363,15 +363,25 @@ sampletime(op::ShiftIndex, _ = nothing) = sampletime(op.clock)
 
 function output_timedomain(x)
     if isoperator(x, Operator)
-        return output_timedomain(operation(x), arguments(x)[])
+        args = arguments(x)
+        return output_timedomain(operation(x), if length(args) == 1
+            args[]
+        else
+            args
+        end)
     else
         throw(ArgumentError("$x of type $(typeof(x)) is not an operator expression"))
     end
 end
 
 function input_timedomain(x)
     if isoperator(x, Operator)
-        return input_timedomain(operation(x), arguments(x)[])
+        args = arguments(x)
+        return input_timedomain(operation(x), if length(args) == 1
+            args[]
+        else
+            args
+        end)
     else
         throw(ArgumentError("$x of type $(typeof(x)) is not an operator expression"))
     end

src/systems/clock_inference.jl

@@ -142,11 +142,16 @@ function infer_clocks!(ci::ClockInference)
             # now we only care about synchronous operators
             iscall(var) || continue
             op = operation(var)
-            is_synchronous_operator(op) || continue
+            if (!is_synchronous_operator(op)) && !(op isa Differential)
+                continue
+            end
 
             # arguments and corresponding time domains
             args = arguments(var)
             tdomains = input_timedomain(op)
+            if !(tdomains isa AbstractArray || tdomains isa Tuple)
+                tdomains = [tdomains]
+            end
             nargs = length(args)
             ndoms = length(tdomains)
             if nargs != ndoms

src/systems/systemstructure.jl

@@ -470,8 +470,9 @@ function TearingState(sys; quick_cancel = false, check = true, sort_eqs = true)
                 addvar!(v, VARIABLE)
                 if iscall(v) && operation(v) isa Symbolics.Operator && !isdifferential(v) &&
                    (it = input_timedomain(v)) !== nothing
-                    v′ = only(arguments(v))
-                    addvar!(setmetadata(v′, VariableTimeDomain, it), VARIABLE)
+                    for v′ in arguments(v)
+                        addvar!(setmetadata(v′, VariableTimeDomain, it), VARIABLE)
+                    end
                 end
             end