Re: Prototyping with Ada (was: Ada featured in Doctor Dobb's Journal)

[John McCabe <john@nospam.assen.demon.co.uk>]

On Sun, 18 May 2008 10:04:17 +0200, Ludovic Brenta
<ludovic@ludovic-brenta.org> wrote:

>> For very prototyping simple projects, scripting languages are fast,
>> but errors and inconsistencies creep in quickly.  The code tends not
>> to last as long because of inflexibility (poor/missing structuring tools
>> such as packages and generics in scripting).

>I agree.  I would even go so far as to say there is no such thing as
>software prototyping.  A prototype is something complex you make
>before mass-producing some sort of physical good, because it is very
>difficult to change the physical system after you've made it, should
>you find any problems.  By definition, you know you're going to throw
>the prototype away at some point.
>
>The opposite is true for software.  If you build a prototype, you can
>always fix problems in it.  And once there are no more problems, the
>prototpye is the "real" software, and you don't throw anything away.

Ah, but this is one of the reasons there is so much poor quality
software around! If you do it right, a prototype should give you an
idea of how you are going to approach a solution, and should show up
certain features or situations that you need to handle, or avoid in
order to make that solution appropriate, reliable and acceptable.

Thus you need to plan for the prototype to be thrown away, because
then you start again taking into account the lessons you learned from
the protoyping exercise.

Of course, if there is some self-contained code that can be re-used,
e.g. a particularly complicated algorithm in its own little "space",
then it is reasonable to do so, as long as you make it more reliable
and so on in the process.

If you approach the whole thing from the point of view you describe,
then you're just taking what may be poor quality code and making it a
bit better, which doesn't necessarily make the code (or design!) good.