IMemoryIndex

IMemoryIndex.cs

 public class FieldSelector<TValue>: Expression<Func<TValue, object>>  {}   

public interface IIndexedDictionary<TKey, TValue> : IEnumerable<TValue>  
        where TKey : IEquatable<TKey>
    {
         // I dont see the value vs 2 steps  , maybe accross multiple indexes...
        // purposes is to apply a brute force predicate on an index eg  ( x =>  return (x == myName); )  
        IEnumerable<KeyValuePair<TKey,TIndexType>> GetSlice<TIndexType>(FieldSelector<TValue> field, TIndexType minValue = default(TIndexType),    TIndexType maxValue  = default(TIndexType)  );  
        
        // the following which returns the objects has not been included so consumers can interact with the store explicitly. 
        //Task<IEnumerable<TValue>> Where(Expression<Func<TValue, bool>> predicate);// concrete will need a convert, Func<IEnumerable<TKey>,Task<IEnumerable<TValue>>> converter);  // if its crossprocess use the above and convert lists  
        IEnumerable<TKey> GetKeysInRange(FieldSelector<TValue> field ,  object minValue ,  object maxValue);  
        IEnumerable<TKey> GetKeysEqual(FieldSelector<TValue> field , object value);  

    
    // concrete type should have 
           // void AddIndex(FieldSelector<TValue> indexes , IComparer comparer = null);   // need sort order should be part of concrete ? or do we need 2 interfaces

    //    void AddIndexes(FieldSelector<TValue> indexes);   // need sort order should be part of concrete ? or do we need 2 interfaces


        // can be not implimented , not sure if it is worth it. By the time you wait for quorum
        //void WaitTillChanged(Tkey id , int timeout = 15);
        
        // This should be on concrete class or  another interface 
        //void AddRange(IEnumerable<KeyValuePair<TKey, TValue>> items); 
    }

  void AddIndexes(IEnumerable<Expression<Func<TValue, object>>> indexes);  if we change the object to a TType you can make betetr judgements  eg uncased string searches.   Maybe be later ?  Or pass in an IComparer on index creation ...

Can we replace object with TIndexType ? We could have a FieldSelector: Expression<Func<TValue, object>> , FieldSelector<TValue, TIndexType>: Expression<Func<TValue, , TIndexType>> maybe possible however we need to hold it in some non generic variable or introduce an interface which is getting expensive..