Re: Software Quality in Science

[Robert A Duff <bobduff@shell01.TheWorld.com>]

Stephen Leake <stephen_leake@stephe-leake.org> writes:

> Georg Bauhaus <rm.tsoh.plus-bug.bauhaus@maps.futureapps.de> writes:
>> His arguments still seem based on studies from the mid 1990s.
>> A study is something at least. Is there anything in the Tokeneer
>> data that could serve as a basis for a comparison?
>> What failure modes might Spark add?

I don't know if you'd call this a "failure mode", but SPARK
has heavy restrictions.  For example, recursion is not allowed.
If I'm writing a compiler, I _will_ be using recursion, because
languages have recursive features (expressions contain
subexpressions, etc).  If the language doesn't support
recursion directly, I will have to implement it myself, using
an explicit stack.  That's error prone, compared to using
recursion in Ada.  So I wouldn't want to write a compiler
in SPARK.

On the other hand, if you don't need recursion and various
other features, then SPARK is an excellent choice.

> Brain pain, for one. Understanding how to use Ada well is an order of
> magnitude harder than understanding how to use C; I suspect SPARK is
> another large increase (I've only looked into it lightly, never tried
> to seriously use it).
>
> I suspect this is one reason Ada has failed to take over the
> programming space; you have to be a really good programmer to fully
> benefit from it, and it's just not worth it for a mediocre programmer.

I'm not sure that's true.  McCormick's paper about toy trains
says otherwise (students were able to produce working code
in Ada, but not in C, even with extra help in the C case).

It's true that Ada is a big language, but a lot of it
can be safely ignored.  There's no need for an Ada
programmer to understand the overload resolution rules,
for example.

- Bob