Re: Is strong typing worth the cost?

[Aidan Skinner <aidan@velvet.net>]

On Thu, 02 May 2002 23:52:46 GMT, Darren New <dnew@san.rr.com> wrote
in <3CD1D17B.F60DCB89@san.rr.com>:

>  subprogram. Which means you can't write a unit test that fails without
>  touching the the production code. Before you can run a test, you have to

Yes you can. It's just that your test suite fails to compile. Which is
a pretty big failure. ;)

>  implement the function called, and then tell the debugger to resume from
>  where it was interrupted.  I haven't seen any Ada system that will let
>  you come close to the ease of debugging that Smalltalk allows.

Neither have I. But then I haven't seen many systems that allow the
ease of debugging that Smalltalk allows.

> > Apparently you are as familiar with Ada
> > as I am with XP.
>  
>  Err, no. Apparently, you don't understand enough about XP to even have
>  an idea of why Ada is poorly suited to it. 

I don't think Ada is really that poorly suited to it. OnceAndOnlyOnce
is harder to achieve than in Smalltalk (for reasonably strict
interpretations of OAOO), but then there are few languages as well
suited to XP as Smalltalk. Which is hardly surprising, given XPs
history.

OTOH, Ada's strong typing can be used to mitigate some of the same
problems as OAOO. Specifically the "one of the versions will be out of
date" problem. In your example the compiler will catch the change of
parameter type and tell me about it. It will take slightly longer to
fix than if it was in Smalltalk, but won't lead to buggy code
compiling.

Further, it's strong typing actively *aids* OAOO in the case where
you're doing range checking etc, you can leave it up to the compiler
in most places. :)

- Aidan
-- 
aidan@velvet.net  http://www.velvet.net/~aidan/  aim:aidans42
finger for pgp key fingerprint |Unix Programmer/Admin actively seeking work
01AA 1594 2DB0 09E3 B850       |CV at http://www.velvet.net/~aidan/cv.txt
C2D0 9A2C 4CC9 3EC4 75E1       |Gis a job, go on, I can do that, go on, gis it.