Eval is a convenient function that parses and evaluates a math expression all in one step.
However, sometimes we want to evaluate the same expression many times in a loop, where only
a the variable changes with each iteration.
Parsing an expression generally takes more time than evaluating it. If maximum speed is of
concern, then Eval is not ideal for this. Instead we'll Parse the expression separately prior
to the loop. Inside the loop we will only evaluate.
#c
For x = 1 To 1000
VariableX.SetVariableValue(x)
Answer = Answer + Expr.Evaluate()
Next
#c