Tidy up remaining documentation and remove unnecessary dependency.

Author: dpad

Project.toml

@@ -12,7 +12,6 @@ DiffRules = "b552c78f-8df3-52c6-915a-8e097449b14b"
 Distributed = "8ba89e20-285c-5b6f-9357-94700520ee1b"
 DocStringExtensions = "ffbed154-4ef7-542d-bbb7-c09d3a79fcae"
 GeneralizedGenerated = "6b9d7cbe-bcb9-11e9-073f-15a7a543e2eb"
-JuliaVariables = "b14d175d-62b4-44ba-8fb7-3064adc8c3ec"
 Latexify = "23fbe1c1-3f47-55db-b15f-69d7ec21a316"
 LightGraphs = "093fc24a-ae57-5d10-9952-331d41423f4d"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
@@ -36,7 +35,6 @@ DiffEqJump = "6.7.5"
 DiffRules = "0.1, 1.0"
 DocStringExtensions = "0.7, 0.8"
 GeneralizedGenerated = "0.1.4, 0.2"
-JuliaVariables = "0.2.0"
 Latexify = "0.11, 0.12, 0.13"
 LightGraphs = "1.3"
 MacroTools = "0.5"

src/function_registration.jl

@@ -10,12 +10,6 @@ ModelingToolkit IR. Example:
 ```
 
 registers `f` as a possible two-argument function.
-
-NOTE: If registering outside of ModelingToolkit (i.e. in your own package),
-this should be done at runtime (e.g. in a package `__init__()`, or inside a
-method that is called at runtime and not during precompile) to ensure that
-any generated functions will use your registered method. See
-`inject_registered_module_functions()`.
 """
 macro register(sig)
     splitsig = splitdef(:($sig = nothing))
@@ -94,24 +88,29 @@ Base.:^(x::Expression,y::T) where T <: Rational = Operation(Base.:^, Expression[
 Base.getindex(x::Operation,i::Int64) = Operation(getindex,[x,i])
 Base.one(::Operation) = 1
 
+# Ensure that Operations that get @registered from outside the ModelingToolkit
+# module can work without having to bring in the associated function into the
+# ModelingToolkit namespace. We basically store information about functions
+# registered at runtime in a ModelingToolkit variable,
+# `registered_external_functions`. It's not pretty, but we are limited by the
+# way GeneralizedGenerated builds a function (adding "ModelingToolkit" to every
+# function call).
 # ---
-# Ensure that Operations that get @registered from outside the ModelingToolkit module can work without
-# having to bring in the associated function into the ModelingToolkit namespace.
-# We basically store information about functions registered at runtime in a ModelingToolkit variable,
-# `registered_external_functions`. It's not pretty, but we are limited by the way GeneralizedGenerated
-# builds a function (adding "ModelingToolkit" to every function call).
-# ---
-import JuliaVariables
 const registered_external_functions = Dict{Symbol,Module}()
 function inject_registered_module_functions(expr)
     MacroTools.postwalk(expr) do x
-        MacroTools.@capture(x, f_(xs__))  # We need to find all function calls in the expression.
-        # If the function call has been converted to a JuliaVariables.Var and matches
-        # one of the functions we've registered...
+        # We need to find all function calls in the expression...
+        MacroTools.@capture(x, f_(xs__))  
+
         if !isnothing(f) && f isa Expr && f.head == :. && f.args[2] isa QuoteNode
-            f_name = f.args[2].value
+            # If the function call matches any of the functions we've
+            # registered, set the calling module (which is probably
+            # "ModelingToolkit") to the module it is registered to.
+            f_name = f.args[2].value  # function name
             f.args[1] = get(registered_external_functions, f_name, f.args[1])
         end
-        return x  # Make sure we rebuild the expression as is.
+
+        # Make sure we rebuild the expression as is.
+        return x
     end
 end