using System;

using HeuristicLab.Common;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.Problems.ProgramSynthesis {

  [Serializable]
  [StorableClass]
  public abstract class Expression : IDeepCloneable, IPooledObject {

    protected Expression() { }

    [StorableConstructor]
    protected Expression(bool deserializing) { }
    protected Expression(Expression origin, Cloner cloner) { }

    public bool IsProgram { get { return GetType() == typeof(PushProgram); } }

    public abstract string StringRepresentation { get; }

    public abstract bool IsNoop(IInternalPushInterpreter interpreter);
    public abstract void Eval(IInternalPushInterpreter interpreter);

    public bool TryEval(IInternalPushInterpreter interpreter) {
      if (IsNoop(interpreter))
        return false;

      Eval(interpreter);
      return true;
    }

    public override string ToString() {
      return StringRepresentation;
    }

    public object Clone() {
      return this;
    }

    public virtual IDeepCloneable Clone(Cloner cloner) {
      return this;
    }

    void IPooledObject.Reset() { }
  }
}