/// <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 Unary(string name, Expr incExpr, double incValue, Operator op, TokenData token)
{
var exp = new UnaryExpr();
exp.Name = name;
exp.Op = op;
exp.Increment = incValue;
exp.Expression = incExpr;
SetupContext(exp, token);
return exp;
}
/// <summary>
/// Evaluate
/// </summary>
/// <returns></returns>
public object VisitUnary(UnaryExpr expr)
{
// Logical not?
if (expr.Op == Operator.LogicalNot)
return EvalHelper.HandleLogicalNot(expr, this);
var valobj = (LObject)expr.Ctx.Memory.Get<object>(expr.Name);
// Double ?
if (valobj.Type == LTypes.Number)
return EvalHelper.IncrementNumber(expr, (LNumber)valobj, this);
// String ?
if (valobj.Type == LTypes.String)
return EvalHelper.IncrementString(expr, (LString)valobj, this);
throw new LangException("Syntax Error", "Unexpected operation", expr.Ref.ScriptName, expr.Ref.Line, expr.Ref.CharPos);
}
public static object HandleLogicalNot(UnaryExpr expr, IAstVisitor visitor)
{
var result = expr.Expression.Evaluate(visitor) as LObject;
// Check 1: This is actually an assert and should not happen.
if (result == null)
throw ExceptionHelper.BuildRunTimeException(expr, "Null value encountered");
var retVal = false;
// Only handle bool for logical not !true !false
if (result.Type == LTypes.Bool)
retVal = !((LBool)result).Value;
else if (result == LObjects.Null)
retVal = true;
return new LBool(retVal);
}
public static LNumber IncrementNumber(UnaryExpr expr, LNumber val, IAstVisitor visitor)
{
var inc = expr.Increment == 0 ? 1 : expr.Increment;
if (expr.Expression != null)
{
var incval = expr.Expression.Evaluate(visitor);
// TODO: Check if null and throw langexception?
inc = ((LNumber)incval).Value;
}
// 1. Calculate the unary value
val = EvalHelper.CalcUnary(val, expr.Op, inc);
// 2. Set the value back into scope
expr.Ctx.Memory.SetValue(expr.Name, val);
return val;
}
public static LString IncrementString(UnaryExpr expr, LString sourceVal, IAstVisitor visitor)
{
// Check 1: Can only do += on strings.
if (expr.Op != Operator.PlusEqual)
throw new LangException("Syntax Error", "string operation with " + expr.Op.ToString() + " not supported", expr.Ref.ScriptName, expr.Ref.Line, expr.Ref.CharPos);
//expr.DataType = typeof(string);
var val = expr.Expression.Evaluate(visitor) as LObject;
// Check 2: Check for null
if (val == LObjects.Null)
return sourceVal;
// Check 3: Limit size if string
Ctx.Limits.CheckStringLength(expr, sourceVal.Value, val.GetValue().ToString());
// Finally do the appending.
var appended = sourceVal.Value + val.GetValue().ToString();
sourceVal.Value = appended;
expr.Ctx.Memory.SetValue(expr.Name, sourceVal);
return sourceVal;
}
public object VisitUnary(UnaryExpr expr)
{
return null;
}
