[Issue 6652] foreach parameter with number range is always ref
d-bugmail at puremagic.com
d-bugmail at puremagic.com
Fri Jun 15 19:55:34 PDT 2012
http://d.puremagic.com/issues/show_bug.cgi?id=6652
Ryuichi OHORI <r.97all at gmail.com> changed:
What |Removed |Added
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CC| |r.97all at gmail.com
--- Comment #11 from Ryuichi OHORI <r.97all at gmail.com> 2012-06-15 19:57:43 PDT ---
(In reply to comment #9)
> I prefer the number 2. I think it breaks none of my programs.
>
> The number 3 is a trap, because it silently changes the semantics of old D
> code. And it's bug-prone for new D programmers too because they can change the
> variable by mistake. Generally immutable variables are safer.
In my point of view, as a newcomer to D, more bug-prone is the current
behavior.
Foreach statement provides iteration over arrays, ranges, etc, and notation of
range "0..n" also *looks like* a collection. So, foreach range statements
should work like foreach over collection.
I have wrote to stuck in my program:
foreach (i; 0..M^^n)
{
foreach (j; 0..n)
{
a[j] = i % M;
i /= M;
}
// operations which use a but i
}
which I wrote in Python before:
for i in range(M**n):
for j in range(n):
a[j] = i % M
i /= M
# operations which use a but i
and was sad to see an infinite loop.
Even a new programmer *intends* to change the value of i when changing, if not
just a typo.
If someone want to affect loop, s/he can write
i = 0;
while (i < 10)
{
// operations which change the value of i
i += 1;
}
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