Thread overview
[Issue 3821] New: writeln doesn't detect recursive data structures yet
Oct 22, 2012
Andrej Mitrovic
Dec 20, 2012
Andrej Mitrovic
February 18, 2010
http://d.puremagic.com/issues/show_bug.cgi?id=3821

           Summary: writeln doesn't detect recursive data structures yet
           Product: D
           Version: 2.040
          Platform: x86
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: druntime
        AssignedTo: sean@invisibleduck.org
        ReportedBy: bearophile_hugs@eml.cc


--- Comment #0 from bearophile_hugs@eml.cc 2010-02-18 11:12:02 PST ---
import std.stdio, std.boxer;
void main() {
    auto a = new Box[1];
    a[0] = box(a);
    writeln(a); // Error: Stack Overflow
}

Produces a stack overflow, the writeln isn't able to detect loops yet.

In Python the print is able to detect loops:

>>> l = [1, 2]
>>> l[1] = l
>>> print l
[1, [...]]

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
October 22, 2012
http://d.puremagic.com/issues/show_bug.cgi?id=3821


Andrej Mitrovic <andrej.mitrovich@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |andrej.mitrovich@gmail.com


--- Comment #1 from Andrej Mitrovic <andrej.mitrovich@gmail.com> 2012-10-21 19:54:33 PDT ---
Got a newer example maybe? std.boxer is long gone.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
December 20, 2012
http://d.puremagic.com/issues/show_bug.cgi?id=3821



--- Comment #2 from Andrej Mitrovic <andrej.mitrovich@gmail.com> 2012-12-20 15:46:13 PST ---
Simple example:

import std.stdio;
import std.string;

class A
{
    B b;
    override string toString() { return format("A(%s)", b.toString()); }
}

class B
{
    A a;
    override string toString() { return format("B(%s)", a.toString()); }
}

void main() {
    auto a = new A;
    auto b = new B;
    a.b = b;
    b.a = a;
    writeln(a);
}

But why is this set for Druntime and to Sean Kelly? This is a Phobos issue imo.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
December 20, 2012
http://d.puremagic.com/issues/show_bug.cgi?id=3821



--- Comment #3 from bearophile_hugs@eml.cc 2012-12-20 15:56:54 PST ---
(In reply to comment #2)

> But why is this set for Druntime and to Sean Kelly? This is a Phobos issue imo.

Maybe I was ignorant. Fixed.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------