How to pack types with variables in one message to send it to another thread? [tuple]
Hi!
I'm trying to make my program multithreaded, and I was stuck at
messaging between threads.
I need to pack types and variables into one message. Will I use
Tuples or something?
e.g.
class Sprite {};
send(tid, Sprite, create, myInt);
Also I don't understand how to use Variant. Messages can be
different, and I don't know how to extract data from variant.
send(tid, One, Two, myInt);
receive(
(Variant args)
{
/*
args contains Tuple!(string, string, int)(One, Two,
42);
I need simple access to data, e.g. args[0] args[1] args[2]
but I don't know how to do this
because `.get` method need precise type of Tuple
*/
}
);
Regards,
MarisaLovesUsAll
Re: How to pack types with variables in one message to send it to another thread? [tuple]
On 7/09/2014 10:42 p.m., MarisaLovesUsAll wrote:
Hi!
I'm trying to make my program multithreaded, and I was stuck at
messaging between threads.
I need to pack types and variables into one message. Will I use Tuples
or something?
e.g.
class Sprite {};
send(tid, Sprite, create, myInt);
Don't worry about the packing when calling send.
It'll automatically be converted into a tuple.
Also you should only be using immutable or primitive types. Strings are
immutable so thats ok. A class instance that isn't immutable isn't.
Note Sprite is a class type not a class instance.
Also I don't understand how to use Variant. Messages can be different,
and I don't know how to extract data from variant.
send(tid, One, Two, myInt);
receive(
(Variant args)
{
/*
args contains Tuple!(string, string, int)(One, Two, 42);
I need simple access to data, e.g. args[0] args[1] args[2]
but I don't know how to do this
because `.get` method need precise type of Tuple
*/
}
);
Don't worry about it.
Just have separate receiving functions per the data type.
You'll probably be better off.
In other words Variant is overkill.
It basically just wraps a piece of data so that it can be passed around
without knowing its type. Which in this case is bad.
You would end up having to know the datatype to do anything with it anyway.
Re: How to pack types with variables in one message to send it to another thread? [tuple]
On Sunday, 7 September 2014 at 10:42:37 UTC, MarisaLovesUsAll
wrote:
Hi!
I'm trying to make my program multithreaded, and I was stuck at
messaging between threads.
I need to pack types and variables into one message. Will I use
Tuples or something?
e.g.
class Sprite {};
send(tid, Sprite, create, myInt);
Also I don't understand how to use Variant. Messages can be
different, and I don't know how to extract data from variant.
send(tid, One, Two, myInt);
receive(
(Variant args)
{
/*
args contains Tuple!(string, string, int)(One, Two,
42);
I need simple access to data, e.g. args[0] args[1]
args[2]
but I don't know how to do this
because `.get` method need precise type of Tuple
*/
}
);
Regards,
MarisaLovesUsAll
receive() automatically expands tuples into multiple arguments.
receive((string s, string t, int i) { });
Re: How to pack types with variables in one message to send it to another thread? [tuple]
Thanks for reply.
Strings are immutable so thats ok. A class instance that isn't
immutable isn't.
It's not a class instance, it's a class type. Something like
`cast(Sprite) null` in parameters. It can be replaced by string
Sprite, but in this case I can't use receive() as it is. E.g.
send(tid,gameobjectId,Sprite,reload);
//must call sprite.reload();
send(tid,gameobjectId,Animation,reload);
//must call animation.reload();
Just have separate receiving functions per the data type.
But both messages are (int, string, string) so they can't be
separate by different receiving functions. It will be better if
messages was (int, Sprite, string) / (int, Animation, string).
And it solves my problem. :) But I don't know how to achieve this.
In other words Variant is overkill.
It basically just wraps a piece of data so that it can be
passed around without knowing its type. Which in this case is
bad.
You would end up having to know the datatype to do anything
with it anyway.
Then I need something like Variant[] to store this data in array.
MyVariant[] args;
if(args[0] == typeid(int))
{
if(args[1] == Sprite) {}
if(args[1] == Animation) {}
}
etc.
I'm trying to make something like messages in Smalltalk (?), but
between threads. Thread can receive anything and thread decides
what to do on its own.
Re: How to pack types with variables in one message to send it to another thread? [tuple]
On 8/09/2014 12:39 a.m., MarisaLovesUsAll wrote:
Thanks for reply.
Strings are immutable so thats ok. A class instance that isn't
immutable isn't.
It's not a class instance, it's a class type. Something like
`cast(Sprite) null` in parameters. It can be replaced by string
Sprite, but in this case I can't use receive() as it is. E.g.
send(tid,gameobjectId,Sprite,reload);
//must call sprite.reload();
send(tid,gameobjectId,Animation,reload);
//must call animation.reload();
Those calls to send are fine.
Just have separate receiving functions per the data type.
But both messages are (int, string, string) so they can't be separate by
different receiving functions. It will be better if messages was (int,
Sprite, string) / (int, Animation, string). And it solves my problem. :)
But I don't know how to achieve this.
In the given send function calls you don't need to. Just use if
statements to check the string type.
In other words Variant is overkill.
It basically just wraps a piece of data so that it can be passed
around without knowing its type. Which in this case is bad.
You would end up having to know the datatype to do anything with it
anyway.
Then I need something like Variant[] to store this data in array.
MyVariant[] args;
if(args[0] == typeid(int))
{
if(args[1] == Sprite) {}
if(args[1] == Animation) {}
}
etc.
No need.
http://dlang.org/phobos/std_concurrency.html#.receive
receive(
(int id, string type, string action) {
if (type == Sprite) {
if (action == reload)
mySprite.reload();
} else if (type == Animation) {
if (action == reload)
myAnimation.reload();
}
}
);
Re: How to pack types with variables in one message to send it to another thread? [tuple]
You can also create new types:
struct UseSprite { string s;}
struct UseAnimation { string s;}
It's not a class instance, it's a class type. Something like
`cast(Sprite) null` in parameters. It can be replaced by string
Sprite, but in this case I can't use receive() as it is. E.g.
send(tid,gameobjectId,Sprite,reload);
//must call sprite.reload();
You could use:
sent(tid, gameobjectId, UseSprite(reload));
send(tid,gameobjectId,Animation,reload);
//must call animation.reload();
sent(tid, gameobjectId, UseAnimation(reload));
Another way, if you have way to determine that gameobjectId points to
an animation or a sprite, would be to define a struct name Reload {}
and then:
sent(tid, gameobjectId, Reload());
Third way: if Animation.reload() and Sprite.reload() are static methods:
send(tid, gameobjectId, Sprite.reload);
But both messages are (int, string, string) so they can't be separate by
different receiving functions. It will be better if messages was (int,
Sprite, string) / (int, Animation, string). And it solves my problem. :)
But I don't know how to achieve this.
See my proposal: define your message as types, directly, and load them
for any data necessary for the call.
UseAnimation(reload), or whatever.
Re: How to pack types with variables in one message to send it to another thread? [tuple]
No need.
Message has additional arguments.
Btw, thanks for help! I found a solution.
struct Message
{
uint id;
string command;
Variant[] args;
this(T...)(uint id, string command, T args)
{
this.id = id;
this.command = command;
this.args = variantArray(args);
}
};
send(tid, cast(immutable Message) Message(id, Sprite, load,
filename));
receive((immutable Message receivedMsg)
{
Message msg = cast(Message) receivedMsg;
writeln(msg.args[1].get!uint);
});
Cast to immutable and back to mutable looks like crutch, but I
don't know what to do with std.concurrency restrictions.
