Expression evaluator

Is a mathematical function parser. It allows you to calculate a value given an expression in string form. It supports the following
operators and functions:

    +       Addition
    -       Substraction
    *       Multiplication
    /       Division
    ^       Exponential (only positive numbers for the base)
    (       Open parenthesis
    )       Close parenthesis
   MOD      MOD operator.  Integers only (if used with floating
            point numbers, it will round the values to integers)

   ABS      (Range: -1e4932..1e4932)
   ATAN     (Range: -1e4932..1e4932)
   COS      (Range: -1e18..1e18)
   EXP      (Range: -11356..11356)
   LN       (Range: 0..1e4932)
   ROUND    (Range: -1e9..1e9)
   SIN      (Range: -1e18..1e18)
   SQRT     (Range: 0..1e4932)
   SQR      (Range: -1e2446..1e2446)
   TRUNC    (Range: -1e9..1e9)