Re: [boost] Flow-based programming library for Boost?

Subject: Re: [boost] Flow-based programming library for Boost?
From: Marcus Tomlinson (themarcustomlinson_at_[hidden])
Date: 2013-01-04 10:35:00

On 04 Jan 2013, at 16:53, "Vicente J. Botet Escriba" <vicente.botet_at_[hidden]> wrote:

> Le 04/01/13 12:56, Marcus Tomlinson a écrit :
>> On Fri, Jan 4, 2013 at 1:24 PM, Vicente J. Botet Escriba <
>> vicente.botet_at_[hidden]> wrote:
>> 
>>> Le 04/01/13 11:36, Marcus Tomlinson a écrit :
>>> 
>>>  On 04 Jan 2013, at 11:46 AM, "Vicente J. Botet Escriba" <
>>> 
>>> 
>>> Could you show a simple example that makes use of this kind of changes?
>>> BTW, what happens when you connect a char and you try to get/set an int or
>>> a complex? Do you get an exception?
>> 
>> Here's an example of the above vector<char> to a vector<int> situation
>> (this component sets the gain of the audio signal passing through it):
>> 
>>   virtual void Process_( DspSignalBus& inputs, DspSignalBus& outputs )
>>   {
>> 
>>     // Audio input of char samples
>> 
>>     std::vector< char > _charStream;
>>     if( inputs.GetValue( 0, _charStream ) )
>>     {
>>       for( unsigned long i = 0; i < _charStream.size(); i++ )
>>       {
>>         _charStream[i] *= _gain;
>>       }
>>       outputs.SetValue( 0, _charStream );
>>     }
>> 
>>     // Audio input of int samples
>> 
>>     std::vector< int > _intStream;
>>     else if( inputs.GetValue( 0, _intStream ) )
>>     {
>>       for( unsigned long i = 0; i < _intStream.size(); i++ )
>>       {
>>         _intStream[i] *= _gain;
>>       }
>>       outputs.SetValue( 0, _intStream );
>>     }
>> 
>>   }
>> 
>> The GetValue() and SetValue() methods simply return false if the type
>> you're trying to get/set is mismatched. We use this in order to determine
>> what data we have received.
> Couldn't this signal (if it is a single one) be split on two signals towards two specific components?
> Or, couldn't a signal with type boost::variant<std::vector<char>, std::vector<int>> be used instead?

Yes and yes :) But the option you choose depends on the application. It could get overly complicated if say, an mp3 decoder component has 20 output ports per sample type, or say a variant that extends across a whole line. Having options means flexibility. And you know how I feel about that :D