Delphi Cookbook - Third Edition

How to do it...

1. We have to create an enumerable function result. The function simply returns the actual enumerable type. This type is not freed automatically by the compiler, so you've got to use a value type or an interfaced type. For the sake of simplicity, let's code to return a record type:

function EachRows(const AFileName: String): TFileEnumerable; 
begin 
  Result := TFileEnumerable.Create(AFileName); 
end; 

2. The TFileEnumerable type is defined as follows:

type 
  TFileEnumerable = record 
  private 
    FFileName: string; 
  public 
    constructor Create(AFileName: String); 
    function GetEnumerator: TEnumerator<String>; 
  end; 
. . . 
constructor TFileEnumerable.Create(AFileName: String); 
begin FFileName := AFileName; end; function TFileEnumerable.GetEnumerator: ...