Re: What Mac developers think of Ada !

[Michael Smith <alphasoft-noone@home.com>]

Well said and thanks.  It saves me the trouble of responding

Nick Roberts wrote:

> Siow Wey Hua,
>
> I applaud your sending in this question to the Darwin mailing list (and
> I think many other on comp.lang.ada will too). Every time someone like
> yourself asks awkward questions about why people use outdated languages
> for outdated reasons helps the cause of improving software in the world,
> even if just a little.
>
> And, because you are not in the Ada 'camp', as it were, your questioning
> has more authority, in effect, than ours could. Please keep asking!
>
> I can think of a few answers to the objections raised by those who
> responded to your question. Please, by all means, put my responses here
> to the mailing list.
>
> ==========
>
> > b) means everything would have to be reoptimized from scratch,
>
> A dubious statement. Most of the 'optimizations' in question would carry
> directly over in the translation. The remainder would probably be
> outshone by the improvement in speed obtained simply by rewriting in
> Ada.
>
> > c) C and Unix are like Strawberries and Champagne, they belong
> > together.
>
> Historically, C and UNIX are, of course, intimately bound up with one
> another. However, Ada 95 has excellent facilities for interfacing with C
> (no worse than for C itself), largely obviating this objection.
>
> > Further, strongly typed and dynamic OOP are for the most part at odds
> > with
> > each other. Ada may be able to replace C++, but it's hardly a fit
> > replacement for the task ObjC is supposed to do.
> > Your suggestion would be much more fit when we were talking about
> > OpenVMS, than when talking about a Unix OS with an dynamic OOP
> > environment.
>
> Misses the point completely. There are large sections of BSD that are
> not - and could not sensibly be - implemented with a dynamic OOP
> language/environment. These are the parts that could and should be
> rewritten in Ada. In addition, much of the infrastructure for a rich
> dynamic OOP environment could also be written (or rewritten) in Ada. A
> dynamic OOP language (preferably a well established one, like SmallTalk
> for example) could then be used to provide the 'upper layers' of the
> overall system (a scheme of which I, personally, thoroughly approve).
>
> > In terms of portability Ada is beaten by C, Java, Cobol...,
>
> In terms of availability of compilers, Ada is beaten by C. But in terms
> of portability of code written in a certain language, Ada beats C (hands
> down). The same is true, to a lesser extent, of Ada versus Java and C++.
> I don't think COBOL is really relevant to the issue.
>
> > in terms of reusability by SmallTalk, ObjC, etc.
>
> Again, dynamic OOP languages are irrelevant. There is difference in
> reusability between Objective C and Ada. However, Ada has the
> acknowledged advantage of fully differentiating the namespace system
> from the type system (which ObjC and C++ do not).
>
> > and in terms of reliability by a slew of smaller languages.
>
> Which are all inadequate for the (entire) job *because* they are too
> small. Using specialist languages for specialized parts of OS should not
> be precluded. But for the bulk of it, a general purpose language is
> necessary.
>
> > Ada is huge, and thus the likelyhood of having bugs in the compiler
> > etc. are much higher than for a small, lean and mean language.
>
> A ludicrous statement, in view of the numerous bugs to be found in C and
> (especially) ObjC and C++ compilers. Standard Ada 95, as a language, is
> smaller
> and simpler than standard C++ and much smaller than Java with its
> (standard) libraries. Much of the greater size of Ada compared to C is
> in the addition of functionality that is provided by library functions
> in C (e.g. multi-tasking). Consider the multi-tasking support inherent
> in the Ada 95 language: it puts C to shame, and is hardly irrelevant to
> the application domain of a multi-tasking operating system!
>
> > For application programming ADA may or may not be appropriate,
> > depending on how much dynamism is required. Interfacing ADA to Cocoa
> > wouldn't be exactly trivial...
>
> Ada is primarily a systems programming language (more so than C, ObjC,
> or C++),
> and interfacing to Cocoa would be straightforward (but not
> trivial, of course).
>
> > Two words: Zero Mindshare.
>
> Two words: closed mind.
>
> ==========
>
> To recap, the arguments that languages such as SmallTalk are preferable
> to Ada are
> irrelevant; the parts of the operating system rewritten in Ada would be
> 100% complementary to the parts that would be written in such languages.
>
> One of the respondents seemed to think that Objective C has some kind of
> dynamism that Ada doesn't. This is not true. Both are static (compiled)
> languages capable of dynamic polymorphism.
>
> I would suggest you reiterate the main advantages of Ada: that the Ada
> language nurtures the development of more reliable, maintainable, and
> reusable code than C, ObjC, C++, or Java; that, in general, code written
> in the Ada
> language is certain to be more portable than that written
> in C, ObjC, C++, or Java; that Ada's emphasis on well-defined interfaces
> between modules is particularly relevant to the Open Source ('bazaar')
> development process; Ada is purpose-designed as a systems programming
> language especially suited to the development of large software.
>
> Of course, I am myself (with others) writing an operating system in Ada.
> Unfortunately, this is a 'hobby' project, with no real source of funds,
> and will therefore inevitably be slow-running and small in scope. It
> would be wonderful for
> a project with the resources of a giant corporation (like Apple) behind
> it to opt for Ada in
> the development of an operating system.
>
> --
> Nick Roberts
> Computer Consultant (UK)
> http://www.callnetuk.com/home/nickroberts
> http://www.adapower.com/lab/adaos

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