#define DEBUG
using System;
using System.Collections.Generic;
using System.Diagnostics;

namespace AspClassic.Parser;

/// <summary>
/// A parse tree for an expression that has an operand.
/// </summary>
public abstract class UnaryExpression : Expression
{
	private readonly Expression _Operand;

	/// <summary>
	/// The operand of the expression.
	/// </summary>
	public Expression Operand => _Operand;

	public override bool IsConstant => Operand.IsConstant;

	protected UnaryExpression(TreeType type, Expression operand, Span span)
		: base(type, span)
	{
		Debug.Assert(type == TreeType.ParentheticalExpression || type == TreeType.TypeOfExpression || type == TreeType.CTypeExpression || type == TreeType.DirectCastExpression || type == TreeType.TryCastExpression || type == TreeType.IntrinsicCastExpression || (type >= TreeType.UnaryOperatorExpression && type <= TreeType.AddressOfExpression));
		if (operand == null)
		{
			throw new ArgumentNullException("operand");
		}
		SetParent(operand);
		_Operand = operand;
	}

	protected override void GetChildTrees(IList<Tree> childList)
	{
		Tree.AddChild(childList, Operand);
	}
}