On Tuesday, 7 August 2012 at 18:08:25 UTC, Araq wrote:
On Tuesday, 7 August 2012 at 10:28:00 UTC, Franciszek Czekała
wrote:
I spent far to much time with Ada (I have and I have read
quite a pile of books on this language). When I tried to write
some sample programs with GNAT using advanced features of this
language I immediately hit on bugs so ridiculous that I was
thrown off the language for good.
For example?
If my memory serves me the bugs were related to postblit
constructors and finalizers (not to mention that these features
are horribly designed and a clear afterthought).
There are no free compilers of this language (which you could
freely use to write commercial programs, like for example
games), no affordable commercial compilers (which you could
buy for ~$500). Ada as a language is DEAD.
FSF's GNAT in GCC is GPL with linking exception, like the rest
of GCC.
If you say "you can't build commercial software" with this, you
can't build commercial software with GCC either.
Check http://libre.adacore.com/comparisonchart/
GNAT GPL edition is meant for "Free Software development
following the terms of the GPL". It is not that the compiler is
GPL protected. It is that your programs created with GNAT are
required to be GPL protected. The difference is related with
licensing of the GNAT runtime which is always a part of compiled
Ada programs. This licensing was changed some time ago to put
restrictions on what you can do with Ada. I spent some time
searching internet forums trying to clear the matter and the
consensus was that you cannot legally use free GNAT to create
closed-source commercial programs.
And you certainly heard about the Ada related catastrophe of
the Ariadne rocket? So much for "safety". Ada is dead and
should not be touched with a mile pole.
http://en.wikipedia.org/wiki/Ariane_5
"Ariane 5's first test flight (Ariane 5 Flight 501) on 4 June
1996 failed, with the rocket self-destructing 37 seconds after
launch because of a malfunction in the control software.[14] A
data conversion from 64-bit floating point value to 16-bit
signed integer value to be stored in a variable representing
horizontal bias caused a processor trap (operand error)[15]
because the floating point value was too large to be
represented by a 16-bit signed integer. The software was
originally written for the Ariane 4 where efficiency
considerations (the computer running the software had an 80%
maximum workload requirement[15]) led to 4 variables being
protected with a handler while 3 others, including the
horizontal bias variable, were left unprotected because it was
thought that they were "physically limited or that there was a
large margin of error".[15] The software, written in Ada, was
included in the Ariane 5 through the reuse of an entire Ariane
4 subsystem despite the fact that the particular software
containing the bug, which was just a part of the subsystem, was
not required by the Ariane 5 because it has a different
preparation sequence[15] than the Ariane 4."
The program was written with Ada and failed in a most stupid way.
Is it not a proof enough that safety cannot be sensibly enforced
by mechanical tools? And this was the main rationale for Ada from
day one. If you check for possible commercial compilers you will
see that most of them remember the days of Windows 95. Ada was
forced on people by administrative means and died when those
means were removed. I wonder how much Ada is in Curiosity on
Mars. Let me guess, 0%?
