Re: dmd 2.049 bug with take and SList?
On Wed, 13 Oct 2010 18:06:15 +, Lars T. Kyllingstad wrote:
On Wed, 13 Oct 2010 16:46:09 +, Nick Treleaven wrote:
Hi,
I'm new to D2 ranges but have been following D for some time. I'm
posting here because I want to check if I'm doing anything wrong before
filing a bug.
The code below is a test case I made after hitting the problem in real
code. Basically the pyramid recursive function should print out: [1, 2,
3]
[1, 2]
[1]
This works fine when calling with an int[] range, but calling with
SList!int seems to make the compiler hang, eating up memory.
Should I file a bug?
import std.stdio;
import std.range;
import std.container;
void pyramid(Range)(Range items)
{
if (items.empty)
return;
writeln(items);
auto len = walkLength(items);
auto r = take(items, len - 1);
pyramid(r);
}
void main()
{
/* array version is fine */
int[] arr = [1, 2, 3];
pyramid(arr[]);
SList!int list = [1, 2, 3];
pyramid(list[]);/* infinite loop with dmd 2.049 */
}
You are creating an infinite recursion of templates. For an array the
return type of take() is the same array type. For other ranges, the
return type of take() is Take!Range. So when you instantiate pyramid!
Range, it instantiates pyramid!(Take!Range), and then
pyramid!(Take!(Take! Range)), and so on ad infinitum.
A solution could be to make take!(Take!Range)() just return another
Take! Range. I can look into that, but you should file a bug report on
it so it's not forgotten.
-Lars
http://d.puremagic.com/issues/show_bug.cgi?id=5052
Re: dmd 2.049 bug with take and SList?
On Thu, 14 Oct 2010 06:54:17 +, Lars T. Kyllingstad wrote:
On Wed, 13 Oct 2010 18:06:15 +, Lars T. Kyllingstad wrote:
On Wed, 13 Oct 2010 16:46:09 +, Nick Treleaven wrote:
Hi,
I'm new to D2 ranges but have been following D for some time. I'm
posting here because I want to check if I'm doing anything wrong
before filing a bug.
The code below is a test case I made after hitting the problem in real
code. Basically the pyramid recursive function should print out: [1,
2, 3]
[1, 2]
[1]
This works fine when calling with an int[] range, but calling with
SList!int seems to make the compiler hang, eating up memory.
Should I file a bug?
import std.stdio;
import std.range;
import std.container;
void pyramid(Range)(Range items)
{
if (items.empty)
return;
writeln(items);
auto len = walkLength(items);
auto r = take(items, len - 1);
pyramid(r);
}
void main()
{
/* array version is fine */
int[] arr = [1, 2, 3];
pyramid(arr[]);
SList!int list = [1, 2, 3];
pyramid(list[]);/* infinite loop with dmd 2.049 */
}
You are creating an infinite recursion of templates. For an array the
return type of take() is the same array type. For other ranges, the
return type of take() is Take!Range. So when you instantiate pyramid!
Range, it instantiates pyramid!(Take!Range), and then
pyramid!(Take!(Take! Range)), and so on ad infinitum.
A solution could be to make take!(Take!Range)() just return another
Take! Range. I can look into that, but you should file a bug report on
it so it's not forgotten.
-Lars
http://d.puremagic.com/issues/show_bug.cgi?id=5052
Fixed.
http://www.dsource.org/projects/phobos/changeset/2102
Re: dmd 2.049 bug with take and SList?
On Thu, 14 Oct 2010 07:18:48 +, Lars T. Kyllingstad wrote: You are creating an infinite recursion of templates. For an array the return type of take() is the same array type. For other ranges, the return type of take() is Take!Range. So when you instantiate pyramid! Range, it instantiates pyramid!(Take!Range), and then pyramid!(Take!(Take! Range)), and so on ad infinitum. OK, makes sense. A solution could be to make take!(Take!Range)() just return another Take! Range. I can look into that, but you should file a bug report on it so it's not forgotten. -Lars http://d.puremagic.com/issues/show_bug.cgi?id=5052 Fixed. http://www.dsource.org/projects/phobos/changeset/2102 Thanks!
