Upsilon/Upsilon/BaseTypes/ScriptIterator.cs

using System;
using System.Collections.Generic;
using Upsilon.BaseTypes.ScriptTypeInterfaces;

namespace Upsilon.BaseTypes
{
    internal abstract class ScriptIterator : ScriptType, IIterable
    {
        public IIterable BaseIterator { get; }
        public override TypeContainer Type => BaseTypes.Type.Table;

        public ScriptIterator(IIterable baseIterator)
        {
            BaseIterator = baseIterator;
        }

        public override object ToCSharpObject()
        {
            return GetScriptEnumerator();
        }

        public override System.Type GetCSharpType()
        {
            return typeof(IEnumerator<ScriptType>);
        }

        public ScriptType GetValueFromIndex(ScriptType index)
        {
            throw new InvalidOperationException();
        }

        public abstract IEnumerator<ScriptType> GetScriptEnumerator();
        public bool Contains(ScriptType obj)
        {
            return false;
        }

        public void Delete(ScriptType key)
        {
            throw new InvalidOperationException();
        }
    }

    internal class UpTillNullPairsScriptIterator : ScriptIterator
    {
        public UpTillNullPairsScriptIterator(IIterable baseIterator) : base(baseIterator)
        {
        }

        public override IEnumerator<ScriptType> GetScriptEnumerator()
        {
            using(var baseEnumerator = BaseIterator.GetScriptEnumerator())
            {
                while (baseEnumerator.MoveNext())
                {
                    var key = baseEnumerator.Current;
                    if (key == null || key.Type == BaseTypes.Type.Nil)
                        break;
                    var value = BaseIterator.GetValueFromIndex(key);
                    if (value.Type == BaseTypes.Type.Nil)
                        break;
                    yield return new SimpleScriptTable(new List<ScriptType>(){key, value});
                }
            }
        }
    }

    internal class PairsScriptIterator : ScriptIterator
    {
        public PairsScriptIterator(IIterable baseIterator) : base(baseIterator)
        {
        }


        public override IEnumerator<ScriptType> GetScriptEnumerator()
        {
            using(var baseEnumerator = BaseIterator.GetScriptEnumerator())
            {
                while (baseEnumerator.MoveNext())
                {
                    var key   = baseEnumerator.Current;
                    var value = BaseIterator.GetValueFromIndex(key);
                    if (value.Type != BaseTypes.Type.Nil)
                        yield return new SimpleScriptTable(new List<ScriptType>(){key, value});
                }
            }
        }
    }

}