/// <summary>
/// Validate a processing instructing test.
/// </summary>
/// <param name="e">
/// is the expression. </param>
/// <returns> null. </returns>
public virtual object visit(PITest e)
{
string arg = e.arg();
if (string.ReferenceEquals(arg, null))
{
arg = "";
}
return(null);
}
/// <param name="e">
/// is the PI test. </param>
/// <returns> e </returns>
public virtual object visit(PITest e)
{
return(null);
}
