safety model in D

[Leandro Lucarella]

Andrei Alexandrescu, el  5 de noviembre a las 08:48 me escribiste:
> First off: _all_ languages except C, C++, and assembler are or at
> least claim to be safe. All. I mean ALL. Did I mention all? If that
> was some ideology that is not realistic, is extremely difficult to
> achieve, and ends up too painful to use, then such theories would be
> difficult to corroborate with "ALL". Walter and I are in agreement
> that safety is not difficult to achieve in D and that it would allow
> a great many good programs to be written.

I think the problem is the cost. The cost for the programmer (the subset
of language features it can use is reduced) and the cost for the compiler
(to increase the subset of language features that can be used, the
compiler has to be much smarter).

Most languages have a lot of developers, and can afford making the
compiler smarter to allow safety with a low cost for the programmer (at
least when writing code, that cost might be higher performance-wise).

A clear example of this, is not being able to take the address of a local.
This is too restrictive to be useful, as you pointed in you post about
having to write static methods because of this. If you can't find
a workaround for this, I guess safety in D can look a little unrealistic.

I like the idea of having a safe subset in D, but I think being
a programming language, *runtime* safety should be *always* a choice for
the user compiling the code.

As other said, you can never be 100% sure your program won't blow for
unknown reasons (it could do that because a bug in the
compiler/interpreter, or even because a hardware problem), you can just
try to make it as difficult as possible, but 100% safety doesn't exist.

-- 
Leandro Lucarella (AKA luca)                     http://llucax.com.ar/
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