On 2011-07-05 08:31:46 +0300, Dmitry Olshansky said:
On 05.07.2011 1:10, bearophile wrote:
Steven Schveighoffer:
Or, use a separate type which throws the errors if you wish.
I have recently explained why this is not good enough, or even
currently impossible:
http://www.digitalmars.com/webnews/newsgroups.php?art_group=digitalmars.D&article_id=139950
I
don't want
runtime errors thrown in code that I didn't intend to throw. most of the
time, overflows will not occur, so I don't want to go through all my code
and have to throw these decorations up where I know it's safe.
The idea is to add two switches to DMD that activate the integral
overflows (one for signed and one for signed and unsigned). If you
compile your code without those, the runtime tests will not happen.
Besides, D is a systems language, and has no business doing checks
on every integer instruction.
This argument doesn't hold, Delphi and Ada too are system languages.
In case of Delphi that's a bit of stretch to say least, e.g. it
_still_ lacks normal pointer arithmetic:
<quote>
In Delphi 2009, pointer arithmetic, as usable for the PChar type (and
PAnsiChar and PWideChar), is now also possible for other pointer
types. When and where this is possible is governed by the new
$POINTERMATH compiler directive.
Pointer arithmetic is generally switched off, but it can be switched on
for a piece of code using|{$POINTERMATH ON}|, and off again
using|{$POINTERMATH OFF}|. For pointer types compiled with pointer
arithmetic (pointer math) turned on, pointer arithmetic is generally
possible.
Apparently, in/Delphi 2009/, the new pointer arithmetic doesn't work as
intended for pointers to/generic/types yet. Whatever type the
parametric type is instantiated as, indices are not scaled
by|SizeOf(T)|, as expected.
</quote>
http://rvelthuis.de/articles/articles-pointers.html
also:
http://stackoverflow.com/questions/4303880/delphi-pointer-arithmetic
Pointer arithmetic is not strictly necessary for a systems language.
Several operating systems were written in Oberon. It has no pointer
arithmetics. Should it be considered not a systems language?
