/// <summary>
/// Evaluates a math expression of 2 units.
/// </summary>
/// <param name="node">The AST node the evaluation is a part of.</param>
/// <param name="left">The unit on the left</param>
/// <param name="right">The unit on the right</param>
/// <param name="op">The math operator</param>
/// <param name="units"></param>
/// <returns></returns>
public static LObject CalcUnits(AstNode node, LUnit left, LUnit right, Operator op, Units units)
{
double baseUnitsValue = 0;
if (op == Operator.Multiply)
{
baseUnitsValue = left.BaseValue * right.BaseValue;
}
else if (op == Operator.Divide)
{
baseUnitsValue = left.BaseValue / right.BaseValue;
}
else if (op == Operator.Add)
{
baseUnitsValue = left.BaseValue + right.BaseValue;
}
else if (op == Operator.Subtract)
{
baseUnitsValue = left.BaseValue - right.BaseValue;
}
else if (op == Operator.Modulus)
{
baseUnitsValue = left.BaseValue % right.BaseValue;
}
var relativeValue = units.ConvertToRelativeValue(baseUnitsValue, left.SubGroup, null);
var result = new LUnit();
result.BaseValue = baseUnitsValue;
result.Group = left.Group;
result.SubGroup = left.SubGroup;
result.Value = relativeValue;
return(new LClass(result));
}