Re: Is strong typing worth the cost?

["Randy Brukardt" <randy@rrsoftware.com>]

Darren New wrote in message <3CD1D17B.F60DCB89@san.rr.com>...

>Now, if I change X to be a date instead of an age, how many places to I
>need to change it? I need to change it two places in Y's body and one
>place in Y's header, and Y doesn't even care whether its argument is an
>age or a date, since it doesn't do anything with it except pass it to
>other functions.

This is a tools problem, not a language problem. I can easily imagine a
programming system for Ada that included a command that let you change
the current declaration and all of its uses. That isn't even that hard
to implement (think ASIS tool).

>It's exactly the same sort of
>wide-spread changing that OO is supposed to reduce.


It seems unusual to be changing your objects so fundementally that you
would want to change the name.

>It requires the subprogram to be declared to compile a call to it, and
>it requires the subprogram to be implemented to link. (The difference
>between being able to compile and being able to link is kind of
academic
>when the goal is to do both at least five times an hour, so I wasn't
>really distinguishing all the steps between "finish writing" and "being
>able to run".)

Again, the whole idea of "compile" and "link" is based on the
"conventional" way to look at Ada. You will find very little in the
standard that assumes this model, for the very simple reason that the
designers believed that it would someday be useful to use a different
model. The only real requirement for error handling in Ada is that
"compile-time" errors are detected before the program begins to execute.

So, again, this is a tools problem. With some imagination, it isn't
unreasonable to think of an Ada programming environment which completely
did away with visible notions of compilation. Essentially, the
environment would compile the source as it is needed; no explicit
commands needed. Certainly, if XP catches on big-time, you'll see
environments like that for all programming languages.

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


I'll grant you that existing Ada environments are poorly suited to XP.
It's unclear if the language really is, or if it is simply a deficiency
of the current environments.

               Randy.