For a long time there's been a style of software development that seeks to describe software systems using a collection of domain specific languages. You see this in the Unix tradition of 'little languages' which generate code via lex and yacc; you see it in the Lisp community with languages developed inside Lisp, often with the help of Lisp's macros. Such approaches are much liked by their advocates, but this style of thinking hasn't caught on as much as many of these people would like.

In the last few years there's been an attempt to support this style of development through a new class of software tool. The earliest and best known of these is Intentional Programming — originally developed by Charles Simonyi while at Microsoft. However there are other people doing similar things too, generating enough momentum to create some interest in this approach.

select customer, item, quantity from header, detail where header_id = detail_id

matrix a = x + y * z;

(loop for i from 1 to 100
      if (evenp i)
        minimize i into min-even and 
        maximize i into max-even and
        unless (zerop (mod i 4))
          sum i into even-not-fours-total
        end
        and sum i into even-total
      else
        minimize i into min-odd and
        maximize i into max-odd and
        when (zerop (mod i 5)) 
          sum i into fives-total
        end
        and sum i into odd-total
      do (update-analysis min-even
                          max-even
                          min-odd
                          max-odd
                          even-total
                          odd-total
                          fives-total
                          even-not-fours-total))