digitalmars.D.bugs - [Issue 4603] New: array(iota(1, 0)) error
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http://d.puremagic.com/issues/show_bug.cgi?id=4603
Summary: array(iota(1, 0)) error
Product: D
Version: D2
Platform: x86
OS/Version: Windows
Status: NEW
Severity: normal
Priority: P2
Component: Phobos
AssignedTo: nobody puremagic.com
ReportedBy: bearophile_hugs eml.cc
This generates an 'Access Violation' with dmd 2.048beta:
import std.range;
void main() {
array(iota(1, 0));
}
The expected result of this array() is an empty dynamic array of signed
integers.
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Aug 09 2010
d-bugmail puremagic.com
http://d.puremagic.com/issues/show_bug.cgi?id=4603
kennytm gmail.com changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |kennytm gmail.com
OS/Version|Windows |All
If you write
---
import std.range;
import std.stdio;
void main() {
foreach (a; iota(1, 0)) {
writeln(a);
}
}
---
the program will never stop writing. Looks like an integer overflow bug.
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Aug 09 2010
http://d.puremagic.com/issues/show_bug.cgi?id=4603 Created an attachment (id=707) Patch for range.d to produce an empty range when pastLast <= current. This patch produces an empty range when pastLast <= current. But this is inconsistent with the behavior of floating point iota ranges. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Aug 09 2010
http://d.puremagic.com/issues/show_bug.cgi?id=4603 Created an attachment (id=708) Patch for range.d to throw when pastLast <= current. This patch simply enforces pastLast > current, so it is consistent with the floating point iota range. But it may be less useful. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Aug 09 2010
http://d.puremagic.com/issues/show_bug.cgi?id=4603
David Simcha <dsimcha yahoo.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |dsimcha yahoo.com
Fixed in changeset 1901. I chose to throw in this case. The proper way to
create an empty range would be to do iota(0, 0), or iota(1, 1). The main
reason for this choice was consistency with array slicing. For example, if
bounds checking is enabled, array[3..2] throws a RangeError.
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Aug 19 2010
http://d.puremagic.com/issues/show_bug.cgi?id=4603 Throwing? No, look at Python:[] It needs to return an empty range. This: foreach (i; iota(1, 0)) is the same as: foreach (i; 1 .. 0) Or: for (int i = 1; i < 0; i++) It's like an empty loop. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------range(1, 0)
Aug 19 2010
http://d.puremagic.com/issues/show_bug.cgi?id=4603 And by the way, in Python This produces an empty string slice:'' -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------"abcdefg"[3:2]
Aug 19 2010
http://d.puremagic.com/issues/show_bug.cgi?id=4603
David Simcha <dsimcha yahoo.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |FIXED
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Aug 19 2010
http://d.puremagic.com/issues/show_bug.cgi?id=4603
bearophile_hugs eml.cc changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |REOPENED
Resolution|FIXED |
Thank you for improving this bug. But I reopen the bug because I think raising
an error is the wrong design. As I have explained iota() is to be meant as the
ranges in for/foreach loops, so iota(1, 0) is like an empty loop, it's not an
error.
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Aug 20 2010
http://d.puremagic.com/issues/show_bug.cgi?id=4603
Andrei Alexandrescu <andrei metalanguage.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|REOPENED |ASSIGNED
CC| |andrei metalanguage.com
AssignedTo|nobody puremagic.com |andrei metalanguage.com
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Jan 09 2011
http://d.puremagic.com/issues/show_bug.cgi?id=4603 See also bug 6222 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Jun 29 2011
http://d.puremagic.com/issues/show_bug.cgi?id=4603
Brad Anderson <eco gnuk.net> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |eco gnuk.net
This now seems to work as you want in DMD 2.059. The following:
import std.stdio, std.range;
void main() {
auto empty_array = array(iota(1, 0));
writeln("type: ", typeof(empty_array).stringof,
", empty? ", empty_array.empty,
", contents: ", empty_array);
}
Outputs:
type: int[], empty? true, contents: []
I'd say it can be closed and marked RESOLVED now.
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Apr 19 2012
http://d.puremagic.com/issues/show_bug.cgi?id=4603
bearophile_hugs eml.cc changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
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Apr 20 2012