Caching with class variables

Recently I was extending a swiss-army-knife helper record we are using at work and I noticed a small piece of suboptimal code. At first I let it be as I couldn’t think of a simple way of improving the code – and the problem was really not so big that it should be fixed with a complicated solution. At some point, however, a simple and elegant solution appeared to me and I like it so much that I want to share it with the world ;)

Parallel Map

At my latest parallel programming presentation a participant suggested that I should extend the OmniThreadLibrary with a parallel mapping abstraction. Dear sir, here is a gift for you.

var
  numbers: TArray<integer>;
  odds   : TArray<string>;
begin
  //initialize the `numbers` array (not shown)
  odds := Parallel.Map<integer,string>(numbers,
    function (const source: integer; var dest: string): boolean
    begin
      Result := Odd(source);
      if Result then
        dest := IntTostr(source);
    end);
  //do something with the `odds` array (not shown)
end;

Using Generics to Manipulate Enumerated Types

I’d like to present a short class written by my colleague at work. Why? Because I just love how it uses the generics syntax to simplify some operations on enumerated types.

Like me, he hated the hoops one must jump through to convert an instance of an enumerated type to a string, to check if an integer value that was read from some storage contains a valid integer representation of some enumerated value and to enumerate (no pun intended) over such a type. Unlike me, he did something about that and wrote a Spring-inspired Range<T>.