Re: op=

2010-01-21 Thread Rainer Deyke 
Ellery Newcomer wrote:
> according to the spec,
> 
> a op= b;
> 
> is semantically equivalent to
> 
> a = a op b;
> 
> but this doesn't seem to be strictly true.


It's untrue in several ways.  For example:

SomeReferenceType a, b;

a = a + b; // Creates new object.
b += c; // Modifies an object in place.

and of course:

a = a = c; // Dual assignment.
a == b; // Equality comparison.


-- 
Rainer Deyke - rain...@eldwood.com

op=

2010-01-21 Thread Ellery Newcomer 

according to the spec,

a op= b;

is semantically equivalent to

a = a op b;

but this doesn't seem to be strictly true. for example:

char c = 'a';
real r = 3.14;

c = c + r; // error

c += r;  // accepted; seems to be doing c += floor(r);

is this behavior intentional?

Re: Synchronized Linked List Traversal

2010-01-21 Thread Steven Schveighoffer 
On Thu, 21 Jan 2010 13:44:53 -0500, Jonathan Crapuchettes  
 wrote:


Yeah, but I have a lot of code in this project that uses phobos and it  
would be a major pain (not to mention the time) to switch over.


Thank you for the thought,
Jonathan


No problem.  You also might consider tangobos, but I'm not sure how  
updated it is WRT tango.


-Steve

Re: Synchronized Linked List Traversal

2010-01-21 Thread Jonathan Crapuchettes 
Yeah, but I have a lot of code in this project that uses phobos and it would be 
a major pain (not to mention the time) to switch over.


Thank you for the thought,
Jonathan

Steven Schveighoffer wrote:

On Thu, 21 Jan 2010 13:29:37 -0500, Jonathan Crapuchettes
 wrote:


Thank you for the help. Since I am using D1, I think I will use the
pthread mutexes through the C API.



Tango provides mutex objects for D1.

-Steve

Re: Synchronized Linked List Traversal

2010-01-21 Thread Steven Schveighoffer 
On Thu, 21 Jan 2010 13:29:37 -0500, Jonathan Crapuchettes  
 wrote:


Thank you for the help. Since I am using D1, I think I will use the  
pthread mutexes through the C API.




Tango provides mutex objects for D1.

-Steve

Re: Synchronized Linked List Traversal

2010-01-21 Thread Jonathan Crapuchettes 
Thank you for the help. Since I am using D1, I think I will use the pthread 
mutexes through the C API.


Steven Schveighoffer wrote:

On Thu, 21 Jan 2010 08:35:50 -0500, Steven Schveighoffer
 wrote:


To do this, you need a manual mutex, look in tango.core.sync.Mutex I
think.


or core.sync.mutex for D2...

-Steve

Re: Synchronized Linked List Traversal

2010-01-21 Thread Steven Schveighoffer 
On Thu, 21 Jan 2010 08:35:50 -0500, Steven Schveighoffer  
 wrote:


To do this, you need a manual mutex, look in tango.core.sync.Mutex I  
think.


or core.sync.mutex for D2...

-Steve

Re: Synchronized Linked List Traversal

2010-01-21 Thread Steven Schveighoffer 
On Wed, 20 Jan 2010 19:25:27 -0500, Jonathan Crapuchettes  
 wrote:


I'm working on a project that requires multi-threading and I am trying  
to grasp the best way to work with setting up a linked-list where  
multiple threads might try to be setting the next element in the list at  
the same time.


What I really need to know is if this will work:

Node!(T) child = parent.firstChild;
synchronized (child)
{
 while (child.sibling !is null)
 child = child.sibling;

 child.sibling = node;
}

What I am worried about is that the mutex will not follow the traversal.  
Any help would be great.


It will not follow the traversal.  Unfortunately, you cannot use the  
synchronized keyword since you cannot do interleaving locks, you must  
manually lock in this pattern:


lock(child)
while(child.sibling !is null)
{
   auto tmp = child;
   child = child.sibling;
   lock(child);
   unlock(tmp);
}
child.sibling = node;
unlock(child);

To do this, you need a manual mutex, look in tango.core.sync.Mutex I think.

But it might also be a better thing to have parent save a pointer to the  
end of the list so you don't traverse the list for every addition...


-Steve