/// <summary>
/// Defines trueness of the specified predicate towards
/// specified token
/// </summary>
/// <param name="tokens"> stack with specified token on top </param>
/// <param name="pr"></param>
/// <returns></returns>
public static bool Check(Stack <IToken> tokens, IPredicateOf1 <IToken> pr)
{
return(tokens.Count != 0 && pr.Execute(tokens.Peek()));
}
/// <summary>
/// Defines trueness of the specified predicate towards
/// char in specified position
/// </summary>
/// <param name="pos"></param>
/// <param name="pr"></param>
/// <returns></returns>
public static bool Check(Position pos, IPredicateOf1 <char> pr)
{
return(!pos.IsEnd &&
!pos.IsBegin &&
pr.Execute(pos.Current));
}