/// <summary>
/// Creates a unary expression with symbol scope, context, script refernce set.
/// </summary>
/// <param name="name"></param>
/// <param name="token"></param>
/// <returns></returns>
public static Expr Negate(Expr expr, TokenData token)
{
var exp = new NegateExpr();
exp.Expression = expr;
SetupContext(exp, token);
return exp;
}
public static object Negate(NegateExpr expr, IAstVisitor visitor)
{
var result = expr.Expression.Visit(visitor) as LObject;
if (result == null)
throw ExceptionHelper.BuildRunTimeException(expr, "Null value encountered");
// Negate number.
if(result.Type == LTypes.Number)
{
var retVal = ((LNumber) result).Value;
retVal = retVal*-1;
return new LNumber(retVal);
}
throw ExceptionHelper.BuildRunTimeException(expr, "Can only convert a number to a negative value");
}
/// <summary>
/// Evaluate
/// </summary>
/// <returns></returns>
public object VisitNegate(NegateExpr expr)
{
return EvalHelper.Negate(expr, this);
}
/// <summary>
/// Evaluate
/// </summary>
/// <returns></returns>
public object VisitNegate(NegateExpr expr)
{
return null;
}