Minor fixes

Author: YingboMa

src/ModelingToolkit.jl

@@ -37,7 +37,8 @@ export @derivatives
 using Symbolics: _parse_vars, value, makesym, @derivatives, get_variables,
                  exprs_occur_in
 import Symbolics: rename, get_variables!, _solve, hessian_sparsity,
-                  jacobian_sparsity, islinear
+                  jacobian_sparsity, islinear, _iszero, _isone,
+                  tosymbol, lower_varname, diff2term, var_from_nested_derivative
 
 import DiffEqBase: @add_kwonly
 
@@ -47,6 +48,18 @@ import TreeViews
 
 using Requires
 
+for fun in [:toexpr]
+    @eval begin
+        function $fun(eq::Equation; kw...)
+            Expr(:(=), $fun(eq.lhs; kw...), $fun(eq.rhs; kw...))
+        end
+
+        $fun(eqs::AbstractArray; kw...) = map(eq->$fun(eq; kw...), eqs)
+        $fun(x::Integer; kw...) = x
+        $fun(x::AbstractFloat; kw...) = x
+    end
+end
+
 """
 $(TYPEDEF)
 
@@ -83,7 +96,6 @@ include("variables.jl")
 include("parameters.jl")
 
 include("utils.jl")
-include("direct.jl")
 include("domains.jl")
 
 include("systems/abstractsystem.jl")
@@ -114,7 +126,6 @@ using .SystemStructures
 
 include("systems/reduction.jl")
 
-include("latexify_recipes.jl")
 include("build_function.jl")
 
 export ODESystem, ODEFunction, ODEFunctionExpr, ODEProblemExpr

src/direct.jl

@@ -427,3 +427,9 @@ function Base.show(io::IO, sys::AbstractSystem)
     end
     return nothing
 end
+
+@latexrecipe function f(sys::AbstractSystem)
+    return latexify(equations(sys))
+end
+
+Base.show(io::IO, ::MIME"text/latex", x::AbstractSystem) = print(io, latexify(x))

src/latexify_recipes.jl

@@ -104,10 +104,6 @@ function ODESystem(
     ODESystem(deqs, iv′, dvs′, ps′, observed, tgrad, jac, Wfact, Wfact_t, name, systems, default_u0, default_p, nothing)
 end
 
-var_from_nested_derivative(x, i=0) = (missing, missing)
-var_from_nested_derivative(x::Term,i=0) = operation(x) isa Differential ? var_from_nested_derivative(arguments(x)[1],i+1) : (x,i)
-var_from_nested_derivative(x::Sym,i=0) = (x,i)
-
 iv_from_nested_derivative(x::Term) = operation(x) isa Differential ? iv_from_nested_derivative(arguments(x)[1]) : arguments(x)[1]
 iv_from_nested_derivative(x::Sym) = x
 iv_from_nested_derivative(x) = missing