refactor: deprecate structural_simplify and @mtkbuild

Author: AayushSabharwal

src/ModelingToolkit.jl

@@ -214,6 +214,7 @@ include("structural_transformation/StructuralTransformations.jl")
 include("inputoutput.jl")
 
 include("adjoints.jl")
+include("deprecations.jl")
 
 const t_nounits = let
     only(@independent_variables t)
@@ -288,7 +289,7 @@ export alias_elimination, flatten
 export connect, domain_connect, @connector, Connection, AnalysisPoint, Flow, Stream,
        instream
 export initial_state, transition, activeState, entry, ticksInState, timeInState
-export @component, @mtkmodel, @mtkcompile
+export @component, @mtkmodel, @mtkcompile, @mtkbuild
 export isinput, isoutput, getbounds, hasbounds, getguess, hasguess, isdisturbance,
        istunable, getdist, hasdist,
        tunable_parameters, isirreducible, getdescription, hasdescription,
@@ -305,7 +306,7 @@ export independent_variable, equations, controls, observed, full_equations, jump
        brownians
 export initialization_equations, guesses, defaults, parameter_dependencies, hierarchy
 export mtkcompile, expand_connections, linearize, linearization_function,
-       LinearizationProblem
+       LinearizationProblem, structural_simplify
 export solve
 export Pre
 

src/deprecations.jl

@@ -0,0 +1,11 @@
+@deprecate structural_simplify(sys; kwargs...) mtkcompile(sys; kwargs...)
+@deprecate structural_simplify(sys, io; kwargs...) mtkcompile(
+    sys; inputs = io[1], outputs = io[2], kwargs...)
+
+macro mtkbuild(exprs...)
+    return quote
+        Base.depwarn("`@mtkbuild` is deprecated. Use `@mtkcompile` instead.", :mtkbuild)
+        @mtkcompile $(exprs...)
+    end |> esc
+end
+

test/structural_transformation/utils.jl

@@ -436,3 +436,10 @@ end
         @test integ.ps[p] ≈ 3.0
     end
 end
+
+@testset "Deprecated `structural_simplify` and `@mtkbuild`" begin
+    @variables x(t)
+    @test_deprecated @mtkbuild sys = System([D(x) ~ x], t)
+    @named sys = System([D(x) ~ x], t)
+    @test_deprecated structural_simplify(sys)
+end