Question nondeterministic constant field

[ArnoStrouwen]

Does the constant field of a Node only come into play for leaf nodes?
It seems nondeterministic for branch nodes when playing around with it in the REPL.

julia> using DynamicExpressions
       
       operators = OperatorEnum(1 => (inv,), 2 => (+,))
       t1 = Node{Float64}(feature=1) + Node{Float64}(feature=2) 
       t1.constant
false

julia> using DynamicExpressions
       
       operators = OperatorEnum(1 => (inv,), 2 => (+,))
       t1 = Node{Float64}(feature=1) + Node{Float64}(feature=2) 
       t1.constant 
false

julia> t2 = Node{Float64}(op=0x1, children=(Node{Float64}(feature=1), Node{Float64}(feature=2)))
       t2.constant
true

julia> using DynamicExpressions
       
       operators = OperatorEnum(1 => (inv,), 2 => (+,))
       t1 = Node{Float64}(feature=1) + Node{Float64}(feature=2) 
       t1.constant
false

julia> t2 = Node{Float64}(op=0x1, children=(Node{Float64}(feature=1), Node{Float64}(feature=2)))
       t2.constant
false

Is the correct deterministic way for determining if a node is operator/constant/feature, to use has_operators and then has_constants?

[MilesCranmer]

It is uninitialised if .degree != 0. In other words you should use checks like n.degree == 0 && n.constant to check if a node is constant or not. Relying on `n.constant' by itself is not valid