I have into FastqReader structure a member named _number and for a strange reason his property return always 0 while into popFront where i do some some operation with, the number is correctly increased: 0,1,2,3 not 0,1,0,1


----------------------------
$ grep _number fastq.d
fastq.d:82:        size_t  _number;
fastq.d:108:                _number++;
fastq.d:113:                    _number++;
fastq.d:162:            return _number;


----------------------------
gdb --args ./fastq ~/Projets/little.fastq
(gdb) b 108
Breakpoint 1 at 0x403ad2: file fastq.d, line 108.
(gdb) b 114
Breakpoint 2 at 0x403b3c: file fastq.d, line 114.
(gdb) b 162
Breakpoint 3 at 0x404022: file fastq.d, line 162.
(gdb) r
Breakpoint 1, fastq.FastqReader.front (this=...) at fastq.d:108
108	                _number++;
(gdb) info args
this = {_currentState = void, _position = 0, _letters = 0, _letterNumber = 0, _number = 0, _mmFile = @0x2aaaaaad2f00}
(gdb) n
134	            Tuple!( State, dchar ) result;
(gdb) info args
this = {_currentState = void, _position = 0, _letters = 0, _letterNumber = 0, _number = 1, _mmFile = @0x2aaaaaad2f00}
(gdb) c
Continuing.

Breakpoint 3, fastq.FastqReader.number (this=...) at fastq.d:162
162	            return _number;
(gdb) info args
this = {_currentState = 0, _position = 0, _letters = 0, _letterNumber = 0, _number = 0, _mmFile = @0x2aaaaaad2f00}
(gdb) watch this._number
Hardware watchpoint 5: this._number
(gdb) c
Continuing.
0 IDENTIFIER @

----------------------------

full code here: http://dpaste.dzfl.pl/4f236648

When i print the memory addres from _number in front method and into number method is not the same while _number should be a member of the given instance;

 ./fastq ~/Projets/little.fastq
-> FastqReader.empty()
-> FastqReader.front()
7FFF355EA0C0, 0, 1
-> FastqReader.number()
7FFF355EA090, 0
0 IDENTIFIER @
-> FastqReader.popFront()
-> FastqReader.empty()
-> FastqReader.empty()
-> FastqReader.empty()
-> FastqReader.front()
-> FastqReader.number()
....
7FFF355EA090, 0
0 QUALITY G
-> FastqReader.popFront()
-> FastqReader.empty()
-> FastqReader.empty()
-> FastqReader.empty()
-> FastqReader.empty()
-> FastqReader.empty()
-> FastqReader.front()
7FFF355EA0C0, 1, 2

----------------

here you see that in front _number is located at 7FFF355EA0C0 and value was 0 and go to 1
while number method return always 0 and _number is located at 7FFF355EA090
And later in front method _number had a value of 1 and go to 2 as intended
number property continue to return 0

This problem appear both with gdc / ldc .
i do not have dmd.
So is maybe a dmdfe bug

I think when i iterate over a phobos range :
  foreach( state, letter; fastq )
and if fastq instance is called into this loop as done at line 181 is not the same instance

below i show that fastq variable do not have same adress into foreach and the followed at line 181

$ gdb --args ./fastq ~/Projets/little.fastq
Reading symbols from /env/export/nfs1/home/jmercier/fastq...done.
(gdb) b 108
Breakpoint 1 at 0x403b9b: file fastq.d, line 108.
(gdb) b 163
Breakpoint 2 at 0x40417f: file fastq.d, line 163.
(gdb) r
Starting program: /env/export/nfs1/home/jmercier/fastq /env/cns/home/jmercier/Projets/little.fastq
warning: no loadable sections found in added symbol-file system-supplied DSO at 0x2aaaaaaab000
[Thread debugging using libthread_db enabled]
-> FastqReader.empty()
-> FastqReader.front()

Breakpoint 1, fastq.FastqReader.front (this=...) at fastq.d:108
108	                _number++;
(gdb) info args
this = {_currentState = void, _position = 0, _letters = 0, _letterNumber = 0, _number = 0, _mmFile = @0x2aaaaaad2f00}
(gdb) p &this._number
$1 = (ulong *) 0x7fffffffd760
(gdb) p &this
$2 = (class FastqReader *) 0x7fffffffd740
(gdb) c
Continuing.
-> FastqReader.number

Breakpoint 2, fastq.FastqReader.number (this=...) at fastq.d:163
163	        }
(gdb) info args
this = {_currentState = 0, _position = 0, _letters = 0, _letterNumber = 0, _number = 0, _mmFile = @0x2aaaaaad2f00}
(gdb) p &this._number
$3 = (ulong *) 0x7fffffffd730
(gdb) p &this
$4 = (struct FastqReader *) 0x7fffffffd710

On 01/31/2013 08:59 AM, bioinfornatics wrote:
> I think when i iterate over a phobos range :
> foreach( state, letter; fastq )
> and if fastq instance is called into this loop as done at line 181 is
> not the same instance

Correct. Here is a simpler program:

import std.stdio;

struct S
{
    int i;

    @property int front() const
    {
        writefln("front   : %s", &i);
        return i;
    }

    @property bool empty() const
    {
        writefln("empty   : %s", &i);
        return i == 0;
    }

    void popFront()
    {
        writefln("popFront: %s", &i);
        --i;
    }
}

void main()
{
    auto s = S(2);
    writefln("main    : %s", &s.i);

    foreach (i; s) {
    }
}

The object in main is a different object:

main    : 7FFFBD429B70
empty   : 7FFFBD429B74
front   : 7FFFBD429B74
popFront: 7FFFBD429B74
empty   : 7FFFBD429B74
front   : 7FFFBD429B74
popFront: 7FFFBD429B74
empty   : 7FFFBD429B74

Ali

On Thursday, 31 January 2013 at 21:31:08 UTC, Ali Çehreli wrote:
> On 01/31/2013 08:59 AM, bioinfornatics wrote:
> > I think when i iterate over a phobos range :
> > foreach( state, letter; fastq )
> > and if fastq instance is called into this loop as done at
> line 181 is
> > not the same instance
>
> Correct. Here is a simpler program:
>
> import std.stdio;
>
> struct S
> {
>     int i;
>
>     @property int front() const
>     {
>         writefln("front   : %s", &i);
>         return i;
>     }
>
>     @property bool empty() const
>     {
>         writefln("empty   : %s", &i);
>         return i == 0;
>     }
>
>     void popFront()
>     {
>         writefln("popFront: %s", &i);
>         --i;
>     }
> }
>
> void main()
> {
>     auto s = S(2);
>     writefln("main    : %s", &s.i);
>
>     foreach (i; s) {
>     }
> }
>
> The object in main is a different object:
>
> main    : 7FFFBD429B70
> empty   : 7FFFBD429B74
> front   : 7FFFBD429B74
> popFront: 7FFFBD429B74
> empty   : 7FFFBD429B74
> front   : 7FFFBD429B74
> popFront: 7FFFBD429B74
> empty   : 7FFFBD429B74
>
> Ali

is normal or is a bug ?

On 01/31/2013 01:42 PM, bioinfornatics wrote:
> On Thursday, 31 January 2013 at 21:31:08 UTC, Ali Çehreli wrote:
>> On 01/31/2013 08:59 AM, bioinfornatics wrote:

>> > I think when i iterate over a phobos range :
>> > foreach( state, letter; fastq )
>> > and if fastq instance is called into this loop as done at
>> line 181 is
>> > not the same instance
>>
>> Correct.

> is normal or is a bug ?

It is not a bug. Here is a discussion on the topic:

  http://forum.dlang.org/thread/jp16ni$fug$1@digitalmars.com

Ali

On Thursday, 31 January 2013 at 22:02:15 UTC, Ali Çehreli wrote:
> On 01/31/2013 01:42 PM, bioinfornatics wrote:
> > On Thursday, 31 January 2013 at 21:31:08 UTC, Ali Çehreli
> wrote:
> >> On 01/31/2013 08:59 AM, bioinfornatics wrote:
>
> >> > I think when i iterate over a phobos range :
> >> > foreach( state, letter; fastq )
> >> > and if fastq instance is called into this loop as done at
> >> line 181 is
> >> > not the same instance
> >>
> >> Correct.
>
> > is normal or is a bug ?
>
> It is not a bug. Here is a discussion on the topic:
>
>   http://forum.dlang.org/thread/jp16ni$fug$1@digitalmars.com
>
> Ali



that is insane ...
so the way to go will be to yield at each loop all members value

This is not related to your actual problem but I have noticed that you have side-effects in your FastqReader.front. I think you will benefit from a design where front simply returns the front element and all of the side-effects are inside popFront().

Ali

On Thursday, 31 January 2013 at 22:20:25 UTC, Ali Çehreli wrote:
> This is not related to your actual problem but I have noticed that you have side-effects in your FastqReader.front. I think you will benefit from a design where front simply returns the front element and all of the side-effects are inside popFront().
>
> Ali

but as fastq instance used to iterate and fastq instance called are not same, any fastq method where depend the position in given range won't work. you need to return all possible value that you could be used