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From: "Nasser M. Abbasi" <nma@12000.org>
Newsgroups: comp.lang.ada
Subject: Re: a new language, designed for safety !
Date: Thu, 05 Jun 2014 04:13:46 -0500
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Date: 2014-06-05T04:13:46-05:00
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On 6/4/2014 2:43 PM, Robert A Duff wrote:

> But I wouldn't call it "unsafe" if you get a run-time error.

This depends if the run-time error could have been avoided in
the first place had the compiler been able to detect the
problem at compile time or not?

With these dynamics languages (Julia, swift, Matlab, etc...),
many errors will show up at run-time, since there is no
static time compiler with a rich language semantics that
allows the compiler to do more analysis and find more errors
even before the program is run.

Even though some dynamic languages will not let one at run
time mix apples and oranges, and will give run-time error,
I'd rather know at compile time that I am not mixing apples
with oranges. That is much more safe.

Many times, one writes a program in a dynamic language
and they would only know there is a bug in the code if
they happen to hit a condition that leads to a
code path at run-time with a bug in it.  There could
be a bug sitting in some corner of the source code
for years and not be detected because of this since it
is hard to test for all code paths all the time.

So one will fly with the code and keep fingers crossed.

On the other hand, dynamic languages are more fun,
since they allow one to hack code so much faster! And
many also come with build-in GUI.

Also they come with really cool modern names such as
"Julia", "Swift", "Hack", "Python", etc..

Compare this to the name "Ada", named after a programmer
who lived hundreds of years ago :)

> To me, "unsafe" means "misuse can cause unpredictable behavior".
> Array indexing is safe in Ada (you get a run-time error if
> you go out of bounds), but unsafe in C (anything can happen
> if you go out of bounds).
>
> Anyway, I guess your point is that Ada prevents dangling dispatch at
> compile time, which is a good thing, whereas Swift, Objective C,
> and Smalltalk do not.
>
> - Bob
>

--Nasser