/// <summary>Sets the wrapped expression, and sets its parent to this node.</summary>
/// <remarks>Sets the wrapped expression, and sets its parent to this node.</remarks>
/// <exception cref="System.ArgumentException">
/// } if expression is
/// <code>null</code>
/// </exception>
public virtual void SetExpression(AstNode expression)
{
AssertNotNull(expression);
expr = expression;
expression.SetParent(this);
SetLineno(expression.GetLineno());
}
/// <summary>
/// Sets the left-hand side of the expression, and sets its
/// parent to this node.
/// </summary>
/// <remarks>
/// Sets the left-hand side of the expression, and sets its
/// parent to this node.
/// </remarks>
/// <param name="left">the left-hand side of the expression</param>
/// <exception cref="System.ArgumentException">
/// } if left is
/// <code>null</code>
/// </exception>
public virtual void SetLeft(AstNode left)
{
AssertNotNull(left);
this.left = left;
// line number should agree with source position
SetLineno(left.GetLineno());
left.SetParent(this);
}