Changes between Version 2 and Version 3 of soc/2007/SignalNetwork

Timestamp:

May 29, 2007, 11:33:14 PM (15 years ago)

Author:

Stjepan Rajko

Comment:

--

soc/2007/SignalNetwork

@@ -60 +60 @@
 
 {{{
+#!cpp
 // connect the generator to filter1
 generator.default_signal().connect(boost::bind(&signal_filter1::operator(), boost::ref(filter1)));
@@ -74 +75 @@
 
 {{{
+#!cpp
 // connect (>>=) generator to filter1,
 // branch (|) from filter1 to both display1 and filter2,
@@ -97 +99 @@
 
 {{{
+#!cpp
 // switch to the other signal generator:
 generator.default_signal().disconnect_all_slots();
@@ -116 +119 @@
 
 {{{
+#!cpp
 // introduce a selector into the network
 signal_selector selector;
@@ -146 +150 @@
 The Signal Network library would provide a set of such commonly needed components,
 such as templates for signal generators, collectors, threading components, etc.
+
+== Interest ==
+The interest for a library such as the Signal Network library was queried in the boost developers mailing list
+message [http://lists.boost.org/Archives/boost/2007/02/116869.php [boost] interest in a "signal flow" library?]
+
+The community reported interest ranging from very interested through conditionally interested
+(this would be interesting if...) to the opinion that using boost::Signals directly would
+be more dependable and readable. Some of the suggestions are summarized in the
+[http://dancinghacker.com/code/signet/ prototype documentation].
+
+Also, there were several mentions of similar "home-brewed" libraries that were in ways similar to the proposed
+Signal Network library, indicating that including a well designed library of this type
+in Boost would be useful to the community.
+
+== Relationships with other libraries ==
+
+The Signal Network library is based directly on Boost.Signals, and throughout the development I plan to maintain
+compatilibility with both the original Boost.Signals library by Doug Gregor and the thread_safe_signals version
+under implementation by Frank Mori Hess (which is geared to replace Boost.Signals).  Most of the tests written
+for the current prototype version of the library work without problems with both base signal implementations.
+
+The library also makes use of Boost.Preprocessor, Boost.!TypeTraits, Boost.Utility
+(call traits and enable_if).  Some parts of the library also use Boost.Threads (for components that are related to threading),
+and Boost.Asio combined with Boost.Serialization (for components that can transmit / receive serializable signals
+through Boost.Asio).
+
+A possible relationship / overlap with
+[http://home.comcast.net/~jturkanis/iostreams/libs/iostreams/doc/home.html Boost.Iostreams] was indicated by Jeff Garland.
+According to its website, Boost.Iostreams serves two main purposes:
+ * To allow the easy creation of standard C++ stream and stream buffer classes for new data sources and sinks.
+ * To provide a convenient interface for defining i/o filters and attaching them to standard streams and stream buffers.
+
+Hence, Boost.Iostreams has similar goals for streams as the Signal Network library has for signals.  The difference is that
+signal networks offer more permanent channels of communication (connecting a signal to a slot makes a lasting
+connection - everything coming out of the signal will be received by the slot until the connection is destroyed),
+while streams offer more of a momentary transfer of information (stream << data makes no permanent connection).
+Boost.Iostreams does allow permanent insertion of filters into a stream, but this does not seem to be intended for more complicated
+network topologies.
+
+Also, [http://channel.sourceforge.net Channel] by Yigong Liu covers a lot of concepts that I hope
+to address in the Signal Network library.  In particular, this library inspired
+designing components that would allow signal
+networks to be constructed accross multiple computers (using Boost.Asio and Boost.Serialization).
+
+== Google Summer of Code Scope ==
+
+Even though a signal network library such as the one proposed above can grow in many directions,
+there is a core functionality requested by the community that can be completed
+as a part of Google Summer of Code.
+
+In particular, the operator-based connection syntax, the development of flow control components,
+the development of signal storage and threading components, and documentation of each are
+feasible for me to complete as a part of Google Summer of Code.
+
+== Download ==
+
+Please see the [http://dancinghacker.com/code/signet/ prototype documentation].
+
+== Acknowledgements ==
+
+Thanks to the [http://ame.asu.edu Arts, Media and Engineering Program] at Arizona State Unversity
+for their support in developing and releasing the prototype Signal Network library code.
+
+Thanks to the Boost community for their valuable suggestions and feedback:
+ * Tobias Schwinger indicated that the library could be used for pulling rather than pushing data.
+ * James Jones suggested that a {{{||}}}-like operator could be used for branching.
+ * Paolo Coletta suggested a "video_generator >>= ( effect1 && effect2 ) >>= image_sum" - like syntax that would allow
+   parallel processing of signals (identified as the "join" pattern by Yigong Liu).
+ * Yigong Liu suggested enhanced support for common network topologies, such as mesh.
+ * Braddock Gaskill pointed out the relationship with the "pipes and filters" pattern, and suggested
+   the possibility of using functions as filters.  He also suggested the library would be more useful
+   if different functions executed in parallel threads, or were queued to specific worker threads,
+   if the library would provide functionality to control and schedule the execution of the invoked functions,
+   or traverse the call graph.
+
+== Copyright ==
+
+The Signal Network library is copyright Stjepan Rajko 2007. Use, modification and
+distribution is subject to the Boost Software License, Version
+1.0. (See copy at
+http://www.boost.org/LICENSE_1_0.txt)
+