Re: Languages don't matter. A mathematical refutation

[Jeffrey Carter <spam.jrcarter.not@spam.not.acm.org>]

On 04/06/2015 03:12 PM, Paul Rubin wrote:
> 
> http://cowlark.com/2014-04-27-ada/index.html says:
> 
>   Personally, I think that the original Ada designers wanted a garbage
>   collector --- a relaxed-rules Ada with closures, inline maps, the
>   ability to have range<> arrays in structures, variable-length strings
>   etc would be totally epic. Unfortunately not only does such a thing
>   not exist, but I have yet to find an implementation that even has a
>   garbage collector. Go figure.
> 
> which I thought was interesting.

The ARM has always been carefully written so as to allow GC without requiring
it, so Ichbiah probably expected compilers with GC to come about. On the other
hand, the Alsys compiler didn't have GC, which might be a better indicator of
what Ichbiah thought Ada should be.

Someone on here named Brukardt has said that he thinks Ichbiah meant for variant
records to be implemented the way Janus/Ada does, not the way GNAT does (I don't
remember how the Alsys compiler implemented this).

In the 1980s some people said they thought Ichbiah intended for compilers to
automatically detect passive tasks and optimize them accordingly, and there were
papers published in /Ada Letters/ on ways to do this, but this all fell by the
wayside when the Ada-9X effort created a completely new construct called
protected types that had some features passive tasks don't (functions) and some
unnecessary restrictions on what they can do (which GNAT ignores by default). No
compiler ever automatically detected passive tasks, including the Alsys
compiler, which again might be the best indicator of what was intended.

In other words, almost everyone who wants something that Ada could do, but that
usually isn't implemented, thinks Ichbiah intended it. Probably what Ichbiah
intended is in the Ada-83 ARM, including all the optional features and the
varying ways to implement others.

-- 
Jeff Carter
"Every sperm is sacred."
Monty Python's the Meaning of Life
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