anchor.diff:      open FParsec
       open FParsec.CharParsers
       open FParsec.Primitives
  +    open FlexSearch.Api.Message
  +    open FlexSearch.Core.Pool
       open System
  +    open System.Linq
       
       /// <summary>
       /// Represents the Values which can be used in the querystring
       /// </summary>
       type Value = 
           | SingleValue of string
  -        | ValueList of Value list
  +        | ValueList of string list
  +        
  +        member this.GetValueAsList() = 
  +            match this with
  +            | SingleValue(v) -> [ v ]
  +            | ValueList(v) -> v
  +        
  +        member this.GetValueAsArray() = 
  +            match this with
  +            | SingleValue(v) -> 
  +                if String.IsNullOrWhiteSpace(v) then Choice2Of2(MessageConstants.MISSING_FIELD_VALUE)
  +                else Choice1Of2([| v |])
  +            | ValueList(v) -> 
  +                if v.Length = 0 then Choice2Of2(MessageConstants.MISSING_FIELD_VALUE)
  +                else Choice1Of2(v.ToArray())
       
       /// <summary>
       /// Acceptable Predicates for a query
  
positive.code:     /// as it is not thread safe. This class will be created using object pool
      /// </summary>    
      type FlexParser() = 
          let opp = new OperatorPrecedenceParser<Predicate, unit, unit>()
          let expr = opp.ExpressionParser
          
  
negative.code:             (stringsSepBy (manySatisfy (fun c -> c <> '\'' && c <> '\\')) (pstring "\\" >>. escape)) |>> SingleValue 
          .>> ws
      
      let stringLiteralList = 
          let escape = anyOf "'" |>> function 
                       | c -> string c // every other char is mapped to itself
          between (pstring "\'") (pstring "\'") 
              (stringsSepBy (manySatisfy (fun c -> c <> '\'' && c <> '\\')) (pstring "\\" >>. escape)) .>> ws
      
      let listOfValues = (str_ws "[" >>. sepBy1 stringLiteralList (str_ws ",") .>> str_ws "]") |>> ValueList .>> ws
      
      /// <summary>
      /// Value parser
  