using System;
using System.Collections.Generic;

namespace Moth.Linq
{
  public delegate TRes Func<TSrc, TRes>(TSrc src);

  public static class Enumerable
  {
    public static IEnumerable<TSrc> Where<TSrc>(this
         IEnumerable<TSrc> source, Func<TSrc, bool> predicate)
    {
      List<TSrc> res = new List<TSrc>();
      foreach (TSrc s in source)
      {
        if (predicate(s))
        {
          res.Add(s);
        }
      }
      
      return res;
    }

    public static IEnumerable<TRes> Select<TSrc, TRes>(this
          IEnumerable<TSrc> source, Func<TSrc, TRes> selector)
    {
      List<TRes> res = new List<TRes>();
      foreach (TSrc s in source)
      {
        TRes t = selector(s);
        res.Add(t);
      }
      
      return res;
    }
  }
}