source: branches/PushGP/HeuristicLab.Algorithms.PushGP/HeuristicLab.Algorithms.PushGP/Expressions/ShoveExpressions.cs @ 14398

using HeuristicLab.Algorithms.PushGP.Interpreter;
using HeuristicLab.Algorithms.PushGP.Stack;

namespace HeuristicLab.Algorithms.PushGP.Expressions
{
    public abstract class ShoveExpression<T> : StatelessExpression
    {
        public void Eval(IStack<T> stack, IStack<long> integerStack, int count = 1)
        {
            if (integerStack.Count == 0)
                return;

            if (integerStack.Top > stack.Count - count ||
                integerStack.Top < 0 ||
                stack.Count < 2)
                return;

            var index = integerStack.Pop();
            var item = stack.Pop();

            // TODO: What if index > int.MaxValue ?
            stack.Insert((int)index, item);
        }
    }

    public class IntegerShoveExpression : ShoveExpression<long>
    {
        protected override string InitStringRepresentation() { return "INTEGER.SHOVE"; }

        public override void Eval(IInterpreter interpreter)
        {
            Eval(interpreter.IntegerStack, interpreter.IntegerStack, 2);
        }
    }

    public class FloatShoveExpression : ShoveExpression<double>
    {
        protected override string InitStringRepresentation() { return "FLOAT.SHOVE"; }

        public override void Eval(IInterpreter interpreter)
        {
            Eval(interpreter.FloatStack, interpreter.IntegerStack);
        }
    }

    public class BooleanShoveExpression : ShoveExpression<bool>
    {
        protected override string InitStringRepresentation() { return "BOOLEAN.SHOVE"; }

        public override void Eval(IInterpreter interpreter)
        {
            Eval(interpreter.BooleanStack, interpreter.IntegerStack);
        }
    }

    public class NameShoveExpression : ShoveExpression<string>
    {
        protected override string InitStringRepresentation() { return "NAME.SHOVE"; }

        public override void Eval(IInterpreter interpreter)
        {
            Eval(interpreter.NameStack, interpreter.IntegerStack);
        }
    }

    public class ExecShoveExpression : ShoveExpression<Expression>
    {
        protected override string InitStringRepresentation() { return "EXEC.SHOVE"; }

        public override void Eval(IInterpreter interpreter)
        {
            Eval(interpreter.ExecStack, interpreter.IntegerStack);
        }
    }

    public class CodeShoveExpression : ShoveExpression<Expression>
    {
        protected override string InitStringRepresentation() { return "CODE.SHOVE"; }

        public override void Eval(IInterpreter interpreter)
        {
            Eval(interpreter.CodeStack, interpreter.IntegerStack);
        }
    }
}