Re: The Fundamental Confusion of Xah

On Sat, 26 Jul 2008 00:10:04 +0100, Jon Harrop <jon@[EMAIL PROTECTED]
>
wrote:

>George Neuner wrote:
>> On Tue, 22 Jul 2008 12:26:02 +0100, Jon Harrop <jon@[EMAIL PROTECTED]
>
>> wrote:
>>>Ada was by far the most successful of those and it does not require
>>>garbage collection and it does not provide closures.
>> 
>> Ada does not *require* GC, but the Boehm collector is available as
>> well as another Ada-specific tracing collector whose name I can't
>> remember just now.  Ada allows overriding the default functions just
>> as in C++.
>> 
>> Also note that Ada does not allow explicit deallocation of a heap
>> object unless you use the optional Unchecked_Deallocation package ...
>> so Ada has to do it for you.  By default, Ada provides a mark-release
>> type region based memory management.  You can also roll your own
>> object based heap management as in C++.
>
>By that definition, C is also garbage collected.

No.  Ada forbids manual deallocation unless the programmer explicitly
marks the code "unchecked" - which results in usage warnings to any
checked code that calls it.  It is not a step taken lightly.

C leaks memory if you do not call free().  Ada does not leak memory
when you do not call Deallocate() - Ada compilers use multiple heaps
with region allocation to provide low cost automatic recycling.  It is
more conservative than GC, but it is a form of automatic memory
management.


>> It's also true that Ada does not provide automatic closures for
>> arbitrary nested functions.  It does, however, provide both objects
>> with private state and concurrent tasks with private environments.
>> Therefore the functional equivalent of a closure is available, as in
>> any OO language and additionally as in a coroutine (Ada tasks can have
>> multiple entry points and can trivially emulate coroutines).
>
>Ada has never had closures.

Did you even bother to read what I said?


>> However Modula2+, Modula-3 and Oberon all *require* GC while
>> permitting explicit memory management as an advanced option.
>
>None of those languages have ever been mainstream.

They are all more mainstream than any ML variant.


>>>In reality, garbage collection became mainstream with Java and closures
>>>are becoming mainstream with C# 3.0.
>> 
>> I see.  You define "mainstream" as whatever wins you the argument.
>
>You think Java and C# 3.0 are not mainstream?

I think you are ignoring evidence of other languages also being
mainstream.  And re: C#, yes, I think it is not mainstream.  C# has
more propaganda than users.


>> Before Java and Python came along, Ada was the 5th most popular
>> general purpose language by number of users.
>
>What gave you that impression?

It's not an impression - it's a fact backed by surveys and commercial
vendor license figures.  Prior to Java's general release in 1995, the
top 10 general purpose programming languages from 1990..1994 according
to Byte magazine and Doctor Dobbs Journal were:

  C/C++ 
  Visual Basic
  Object Pascal
  COBOL
  Ada
  C
  Fortran
  Lisp
  Prolog
  Smalltalk

Visual Basic actually sold more licenses than all the commercial C++
compilers combined, but the free availability of GCC kept C++ on top.
The Object Pascal dialect was sold as Turbo Pascal and as Macintosh
Pascal.  By 1994, most Mac programmers had transitioned to C++, but
some 25% still used Macintosh Pascal.

COBOL - what the hell can I say.  Companies still use it and according
to some surveys, there are as many COBOL programs as there are
programs in C++.  COBOL just won't die.

In 1994, Ada was required for programming any DOD application and was
the preferred language for US government programming contracts - a
guaranteed large user base.  It was then, and still is now, the second
most widely used language for embedded programming (after C)
accounting for 1/3 of all projects.  Ada is still required for most
aerospace applications and is still the preferred language for
industrial robotic control and safety critical applications such as
chemical and nuclear plant operations.


The top 10 list is different now.  Java, Python and C# have come onto
it - Fortran, Prolog and Smalltalk have fallen off.  But oddly enough,
Objective Pascal (aka Delphi), COBOL and Ada are still on it and ML
still isn't.


>> It still has more users than all the ML variants combined.
>
>What gave you that impression?

The number of programmers employed in application areas that prefer
Ada to other languages.

What gives you your impressions?  Google fights?


George
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