Added function to create variables without @variables macro

genvar(::Symbol) now converts a ::Symbol into a Symbolics.jl variable. "genvar(:f)" or "genvar(:f, :t)" (t is the default) is now equivalent to "@variables f(t)". Multiple dependent variables can be used, e.g., "genvar(:f, [:t, :d1, :d2])", as long as the dependent variables have been declared previously as variables or parameters.

Author: RXGottlieb

src/transform/utilities.jl

@@ -15,4 +15,26 @@ zstr(a::Assignment) = string_or_num(a.lhs)
 
 string_or_num(a::Expr) = string(a)
 string_or_num(a::Symbol) = string(a)
-string_or_num(a::Number) = a
+string_or_num(a::Number) = a
+
+# Uses Symbolics functions to generate a variable as a function of the dependent variables of choice (default: t)
+function genvar(a::Symbol, b=:t)
+    vars = Symbol[]
+    ex = Expr(:block)
+    var_name, expr = Symbolics.construct_vars(:variables, a, Real, [b], nothing, nothing, identity, false)
+    push!(vars, var_name)
+    push!(ex.args, expr)
+    rhs = Symbolics.build_expr(:vect, vars)
+    push!(ex.args, rhs)
+    eval(ex)
+end
+function genvar(a::Symbol, b::Vector{Symbol})
+    vars = Symbol[]
+    ex = Expr(:block)
+    var_name, expr = Symbolics.construct_vars(:variables, a, Real, b, nothing, nothing, identity, false)
+    push!(vars, var_name)
+    push!(ex.args, expr)
+    rhs = Symbolics.build_expr(:vect, vars)
+    push!(ex.args, rhs)
+    eval(ex)
+end