Merged -r 5137:5174 from developer branch jcorgan/hb. Trunk passes distcheck. Converts gr.hier_block2 API to not use 'define_component' methodology anymore.

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@5177 221aa14e-8319-0410-a670-987f0aec2ac5

25 files changed, 968 insertions, 1379 deletions

diff --git a/gnuradio-core/src/lib/runtime/Makefile.am b/gnuradio-core/src/lib/runtime/Makefile.am
index 91d3c144b..ee71fcdbc 100644
--- a/gnuradio-core/src/lib/runtime/Makefile.am
+++ b/gnuradio-core/src/lib/runtime/Makefile.am
@@ -129,7 +129,6 @@ swiginclude_HEADERS =			\
 	gr_msg_queue.i			\
 	gr_realtime.i			\
 	gr_runtime.i			\
-	gr_simple_flowgraph.i		\
 	gr_single_threaded_scheduler.i	\
 	gr_sync_block.i			\
 	gr_sync_decimator.i		\
diff --git a/gnuradio-core/src/lib/runtime/gr_hier_block2.cc b/gnuradio-core/src/lib/runtime/gr_hier_block2.cc
index 65dea95fb..d5ed4ccc9 100644
--- a/gnuradio-core/src/lib/runtime/gr_hier_block2.cc
+++ b/gnuradio-core/src/lib/runtime/gr_hier_block2.cc
@@ -1,6 +1,6 @@
 /* -*- c++ -*- */
 /*
- * Copyright 2006 Free Software Foundation, Inc.
+ * Copyright 2006,2007 Free Software Foundation, Inc.
  * 
  * This file is part of GNU Radio
  * 
@@ -50,14 +50,15 @@ gr_hier_block2::~gr_hier_block2()
 }
 
 void 
-gr_hier_block2::define_component(const std::string &name, gr_basic_block_sptr block)
+gr_hier_block2::connect(gr_basic_block_sptr src, int src_port, 
+                        gr_basic_block_sptr dst, int dst_port)
 {
-    d_detail->define_component(name, block);
+    d_detail->connect(src, src_port, dst, dst_port);
 }
 
 void 
-gr_hier_block2::connect(const std::string &src_name, int src_port, 
-                        const std::string &dst_name, int dst_port)
+gr_hier_block2::disconnect(gr_basic_block_sptr src, int src_port, 
+                           gr_basic_block_sptr dst, int dst_port)
 {
-    d_detail->connect(src_name, src_port, dst_name, dst_port);
+    d_detail->disconnect(src, src_port, dst, dst_port);
 }
diff --git a/gnuradio-core/src/lib/runtime/gr_hier_block2.h b/gnuradio-core/src/lib/runtime/gr_hier_block2.h
index 9d2dd3569..53a23bb47 100644
--- a/gnuradio-core/src/lib/runtime/gr_hier_block2.h
+++ b/gnuradio-core/src/lib/runtime/gr_hier_block2.h
@@ -1,6 +1,6 @@
 /* -*- c++ -*- */
 /*
- * Copyright 2006 Free Software Foundation, Inc.
+ * Copyright 2006,2007 Free Software Foundation, Inc.
  * 
  * This file is part of GNU Radio
  * 
@@ -59,9 +59,10 @@ protected:
 public:
     virtual ~gr_hier_block2();
 
-    void define_component(const std::string &name, gr_basic_block_sptr basic_block);
-    void connect(const std::string &src_name, int src_port, 
-                 const std::string &dst_name, int dst_port);
+    void connect(gr_basic_block_sptr src, int src_port, 
+                 gr_basic_block_sptr dst, int dst_port);
+    void disconnect(gr_basic_block_sptr src, int src_port,
+	            gr_basic_block_sptr dst, int dst_port);
 };
 
 #endif /* INCLUDED_GR_HIER_BLOCK2_H */
diff --git a/gnuradio-core/src/lib/runtime/gr_hier_block2.i b/gnuradio-core/src/lib/runtime/gr_hier_block2.i
index c5a676534..f9a126fe2 100644
--- a/gnuradio-core/src/lib/runtime/gr_hier_block2.i
+++ b/gnuradio-core/src/lib/runtime/gr_hier_block2.i
@@ -1,6 +1,6 @@
 /* -*- c++ -*- */
 /*
- * Copyright 2005 Free Software Foundation, Inc.
+ * Copyright 2005,2006,2007 Free Software Foundation, Inc.
  * 
  * This file is part of GNU Radio
  * 
@@ -44,9 +44,10 @@ public:
     ~gr_hier_block2 ();
 
     // Add a named block to the container
-    void define_component(const std::string &name, gr_basic_block_sptr basic_block)
+    void connect(gr_basic_block_sptr src, int src_port,
+                 gr_basic_block_sptr dst, int dst_port)
         throw (std::invalid_argument);
-    void connect(const std::string &src_name, int src_port,
-                 const std::string &dst_name, int dst_port)
+    void disconnect(gr_basic_block_sptr src, int src_port,
+                    gr_basic_block_sptr dst, int dst_port)
         throw (std::invalid_argument);
 };
diff --git a/gnuradio-core/src/lib/runtime/gr_hier_block2_detail.cc b/gnuradio-core/src/lib/runtime/gr_hier_block2_detail.cc
index 545a64bfd..b41d0c65c 100644
--- a/gnuradio-core/src/lib/runtime/gr_hier_block2_detail.cc
+++ b/gnuradio-core/src/lib/runtime/gr_hier_block2_detail.cc
@@ -1,5 +1,5 @@
 /*
- * Copyright 2006 Free Software Foundation, Inc.
+ * Copyright 2006,2007 Free Software Foundation, Inc.
  * 
  * This file is part of GNU Radio
  * 
@@ -29,199 +29,157 @@
 #include <stdexcept>
 #include <iostream>
 
+#define GR_HIER_BLOCK2_DETAIL_DEBUG 1
+
 gr_hier_block2_detail::gr_hier_block2_detail(gr_hier_block2 *owner) :
-d_owner(owner)
+  d_owner(owner), 
+  d_fg(gr_make_simple_flowgraph()),
+  d_inputs(owner->input_signature()->max_streams()),
+  d_outputs(owner->output_signature()->max_streams())
 {
 }
 
 gr_hier_block2_detail::~gr_hier_block2_detail()
 {
-    d_owner = 0; // Don't use delete, we didn't allocate
-}
-
-gr_basic_block_sptr
-gr_hier_block2_detail::lookup_block(const std::string &name)
-{
-    gr_hier_component_miter_t p = d_components.find(name);
-    if (p != d_components.end())
-        return p->second;
-    else
-        return gr_basic_block_sptr();
+  d_owner = 0; // Don't use delete, we didn't allocate
 }
 
 void 
-gr_hier_block2_detail::define_component(const std::string &name, gr_basic_block_sptr block)
+gr_hier_block2_detail::connect(gr_basic_block_sptr src, int src_port, 
+                               gr_basic_block_sptr dst, int dst_port)
 {
-    if (!block)
-	throw std::invalid_argument("null block passed");
-
-    if (name == "self")
-        throw std::invalid_argument("name is reserved");
-
-    // TODO: reject names with '.' inside
-    
-    if (!lookup_block(name))
-        d_components[name] = block;
-    else
-        throw std::invalid_argument("name already in use");
+  if (GR_HIER_BLOCK2_DETAIL_DEBUG)
+    std::cout << "connecting: " << gr_endpoint(src, src_port)
+              << " -> " << gr_endpoint(dst, dst_port) << std::endl;
+
+  if (src.get() == dst.get())
+    throw std::invalid_argument("src and destination blocks cannot be the same");
+
+  // Assignments to block inputs or outputs
+  int max_port;
+  if (src.get() == d_owner) {
+    max_port = src->input_signature()->max_streams();
+    if ((max_port != -1 && (src_port >= max_port)) || src_port < 0)
+      throw std::invalid_argument("source port out of range");
+    return assign_input(src_port, dst_port, dst);
+  }
+
+  if (dst.get() == d_owner) {
+    max_port = dst->output_signature()->max_streams();
+    if ((max_port != -1 && (dst_port >= max_port)) || dst_port < 0)
+      throw std::invalid_argument("source port out of range");
+    return assign_output(dst_port, src_port, src);
+  }
+
+  // Internal connections
+  d_fg->connect(src, src_port, dst, dst_port);
+
+  // TODO: connects to NC
 }
 
 void 
-gr_hier_block2_detail::connect(const std::string &src_name, int src_port, 
-                               const std::string &dst_name, int dst_port)
+gr_hier_block2_detail::disconnect(gr_basic_block_sptr src, int src_port, 
+                                  gr_basic_block_sptr dst, int dst_port)
 {
-    gr_io_signature_sptr src_io_signature;
-    gr_io_signature_sptr dst_io_signature;
-    
-    // Check against our *input_signature* if we're wiring from one of our external inputs
-    if (src_name == "self") 
-        src_io_signature = d_owner->input_signature();
-    else {
-        gr_basic_block_sptr src_block = lookup_block(src_name);
-        if (!src_block)
-            throw std::invalid_argument("undefined src name");
-        src_io_signature = src_block->output_signature();
-    }
-    
-    // Check against our *output_signature* if we're wiring to one of our external outputs
-    if (dst_name == "self") 
-    	dst_io_signature = d_owner->output_signature();
-    else {
-        gr_basic_block_sptr dst_block = lookup_block(dst_name);
-        if (!dst_block)
-            throw std::invalid_argument("undefined dst name");
-        dst_io_signature = dst_block->input_signature();
-    }
-    
-    // Check port numbers are valid
-    check_valid_port(src_io_signature, src_port);
-    check_valid_port(dst_io_signature, dst_port);
-
-    // Check destination port not already in use
-    check_dst_not_used(dst_name, dst_port);
-
-    // Check endpoint types match
-    check_type_match(src_io_signature, src_port, dst_io_signature, dst_port);
-
-    d_edges.push_back(gr_make_edge(src_name, src_port, dst_name, dst_port));
-}
+  // Handle disconnecting inputs and outputs
 
-void 
-gr_hier_block2_detail::check_valid_port(gr_io_signature_sptr sig, int port)
-{
-    if (port < 0)
-        throw std::invalid_argument("port number must not be negative");
-	
-    if (sig->max_streams() >= 0 && port >= sig->max_streams())
-        throw std::invalid_argument("port number exceeds max streams");
+  d_fg->disconnect(src, src_port, dst, dst_port);
 }
 
-void 
-gr_hier_block2_detail::check_dst_not_used(const std::string name, int port)
+void
+gr_hier_block2_detail::assign_input(int my_port, int port, gr_basic_block_sptr block)
 {
-    for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++)
-        if ((*p)->dst_name() == name && (*p)->dst_port() == port)
-            throw std::invalid_argument("destination port in use");
-}
+  if (my_port < 0 || my_port >= (signed)d_inputs.size())
+    throw std::invalid_argument("input port number out of range");
 
-void 
-gr_hier_block2_detail::check_type_match(gr_io_signature_sptr src_sig, int src_port,
-                                        gr_io_signature_sptr dst_sig, int dst_port)
-{
-    if (src_sig->sizeof_stream_item(src_port) != dst_sig->sizeof_stream_item(dst_port))
-        throw std::invalid_argument("type mismatch");
-}
+  if (d_inputs[my_port].block())
+    throw std::invalid_argument("input port in use");
 
-std::string
-gr_hier_block2_detail::prepend_prefix(const std::string &prefix, const std::string &str)
-{
-    return prefix + ((prefix == "") ? "" : ".") + str;
+  d_inputs[my_port] = gr_endpoint(block, port);
 }
 
-gr_endpoint
-gr_hier_block2_detail::match_endpoint(const std::string &name, int port, bool is_input)
+void
+gr_hier_block2_detail::assign_output(int my_port, int port, gr_basic_block_sptr block)
 {
-    for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++) {
-        if (is_input) {
-            if ((*p)->src_name() == name && (*p)->src_port() == port)
-                return resolve_endpoint((*p)->dst_name(), (*p)->dst_port(), "", !is_input);
-	    }
-        else {
-            if ((*p)->dst_name() == name && (*p)->dst_port() == port)
-                return resolve_endpoint((*p)->src_name(), (*p)->src_port(), "", !is_input);
-        }
-    }
-
-    // Should never get here
-    throw std::runtime_error("unable to match endpoint");
-}
+  if (my_port < 0 || my_port >= (signed)d_outputs.size())
+    throw std::invalid_argument("output port number out of range");
 
-gr_endpoint
-gr_hier_block2_detail::resolve_endpoint(const std::string &name, int port, 
-                                        const std::string &prefix, bool is_input)
-{
-    gr_basic_block_sptr basic_block = lookup_block(name);
-
-    // Check if 'name' points to gr_block (leaf node)
-    gr_block_sptr block(boost::dynamic_pointer_cast<gr_block, gr_basic_block>(basic_block));
-    if (block)
-        return gr_endpoint(prepend_prefix(prefix, name), port);
-
-    // Check if 'name' points to hierarchical block
-    gr_hier_block2_sptr hier_block2(boost::dynamic_pointer_cast<gr_hier_block2, gr_basic_block>(basic_block));
-    if (hier_block2) {
-        std::string child_prefix = prepend_prefix(prefix, name);
-        gr_endpoint match(hier_block2->d_detail->match_endpoint("self", port, !is_input));
-        return gr_endpoint(prepend_prefix(child_prefix, match.name()), match.port());
-    }
-
-    // Shouldn't ever get here
-    throw std::runtime_error("unable to resolve endpoint");
+  if (d_outputs[my_port].block())
+    throw std::invalid_argument("output port in use");
+
+  d_outputs[my_port] = gr_endpoint(block, port);
 }
 
-void
-gr_hier_block2_detail::flatten(gr_simple_flowgraph_sptr sfg, const std::string &prefix)
+gr_endpoint
+gr_hier_block2_detail::resolve_port(int port, bool is_input)
 {
-    flatten_components(sfg, prefix);
-    flatten_edges(sfg, prefix);
+  if (GR_HIER_BLOCK2_DETAIL_DEBUG)
+    std::cout << "Resolving port " << port << " as an "
+	      << (is_input ? "input" : "output")
+	      << " of " << d_owner->name() << std::endl;
+
+  gr_endpoint result;
+
+  if (is_input) {
+    if (port < 0 || port >= (signed)d_inputs.size())
+      throw std::runtime_error("input port number out of range");
+    result = resolve_endpoint(d_inputs[port], true);
+  }
+  else {
+    if (port < 0 || port >= (signed)d_outputs.size())
+      throw std::runtime_error("output port number out of range");
+    result = resolve_endpoint(d_outputs[port], false);
+  }
+
+  if (!result.block())
+    throw std::runtime_error("unable to resolve port");
+
+  return result;
 }
 
-void
-gr_hier_block2_detail::flatten_components(gr_simple_flowgraph_sptr sfg, const std::string &prefix)
+gr_endpoint
+gr_hier_block2_detail::resolve_endpoint(const gr_endpoint &endp, bool is_input)
 {
-    // Add my non-hierarchical components to the simple flowgraph, then recurse
-    for (gr_hier_component_miter_t p = d_components.begin(); p != d_components.end(); p++) {
-        std::string name = prepend_prefix(prefix, p->first);
-
-        gr_basic_block_sptr basic_block = p->second;
-        gr_block_sptr block(boost::dynamic_pointer_cast<gr_block, gr_basic_block>(basic_block));
-        if (block)	
-            sfg->define_component(name, block);
-
-        gr_hier_block2_sptr hier_block2(boost::dynamic_pointer_cast<gr_hier_block2, gr_basic_block>(basic_block));
-        if (hier_block2)
-            hier_block2->d_detail->flatten_components(sfg, name);
-    }
+  // Check if endpoint is a leaf node
+  if (boost::dynamic_pointer_cast<gr_block, gr_basic_block>(endp.block()))
+    return endp;
+  
+  // Check if endpoint is a hierarchical block
+  gr_hier_block2_sptr hier_block2(boost::dynamic_pointer_cast<gr_hier_block2, gr_basic_block>(endp.block()));
+  if (hier_block2) {
+    if (GR_HIER_BLOCK2_DETAIL_DEBUG)
+      std::cout << "Resolving endpoint " << endp << " as an " 
+		<< (is_input ? "input" : "output")
+		<< ", recursing" << std::endl;
+    return hier_block2->d_detail->resolve_port(endp.port(), is_input);
+  }
+
+  // Shouldn't ever get here
+  throw std::runtime_error("block is not a valid gr_block or gr_hier_block2!");
 }
 
 void
-gr_hier_block2_detail::flatten_edges(gr_simple_flowgraph_sptr sfg, const std::string &prefix)
+gr_hier_block2_detail::flatten(gr_simple_flowgraph_sptr sfg)
 {
-    // Add my edges to the flow graph, resolving references to actual endpoints
-    for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++) {
-    	// Connections to self get resolved/added by parent if actually connected
-        if ((*p)->src_name() == "self" || (*p)->dst_name() == "self")
-            continue;
-
-        gr_endpoint src_endp = resolve_endpoint((*p)->src_name(), (*p)->src_port(), prefix, true);
-        gr_endpoint dst_endp = resolve_endpoint((*p)->dst_name(), (*p)->dst_port(), prefix, false);
-        sfg->connect(src_endp.name(), src_endp.port(), dst_endp.name(), dst_endp.port());
-    }
-
-    // Recurse hierarchical children
-    for (gr_hier_component_miter_t p = d_components.begin(); p != d_components.end(); p++) {
-        gr_hier_block2_sptr hier_block2(boost::dynamic_pointer_cast<gr_hier_block2, gr_basic_block>(p->second));
-        if (hier_block2)
-            hier_block2->d_detail->flatten_edges(sfg, prepend_prefix(prefix, p->first));
-    }
+  if (GR_HIER_BLOCK2_DETAIL_DEBUG)
+    std::cout << "flattening " << d_owner->name() << std::endl;
+
+  // Add my edges to the flow graph, resolving references to actual endpoints
+  for (gr_edge_viter_t p = d_fg->d_detail->d_edges.begin(); p != d_fg->d_detail->d_edges.end(); p++) {
+    if (GR_HIER_BLOCK2_DETAIL_DEBUG)
+      std::cout << "Flattening edge " << (*p) << std::endl;
+
+    gr_endpoint src_endp = resolve_endpoint((*p)->src(), false);
+    gr_endpoint dst_endp = resolve_endpoint((*p)->dst(), true);
+    sfg->connect(src_endp, dst_endp);
+  }
+
+  gr_basic_block_vector_t blocks = d_fg->d_detail->calc_used_blocks();
+
+  // Recurse hierarchical children
+  for (gr_basic_block_viter_t p = blocks.begin(); p != blocks.end(); p++) {
+    gr_hier_block2_sptr hier_block2(boost::dynamic_pointer_cast<gr_hier_block2, gr_basic_block>(*p));
+    if (hier_block2)
+      hier_block2->d_detail->flatten(sfg);
+  }
 }
diff --git a/gnuradio-core/src/lib/runtime/gr_hier_block2_detail.h b/gnuradio-core/src/lib/runtime/gr_hier_block2_detail.h
index 095bd40f5..f0e7b7e82 100644
--- a/gnuradio-core/src/lib/runtime/gr_hier_block2_detail.h
+++ b/gnuradio-core/src/lib/runtime/gr_hier_block2_detail.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2006 Free Software Foundation, Inc.
+ * Copyright 2006,2007 Free Software Foundation, Inc.
  * 
  * This file is part of GNU Radio
  * 
@@ -25,9 +25,6 @@
 #include <gr_simple_flowgraph_detail.h>
 #include <boost/utility.hpp>
 
-typedef std::map<std::string, gr_basic_block_sptr> gr_hier_component_map_t;
-typedef std::map<std::string, gr_basic_block_sptr>::iterator gr_hier_component_miter_t;
-
 class gr_hier_block2_detail : boost::noncopyable
 {
 private:
@@ -39,26 +36,21 @@ private:
 
     // Private implementation data
     gr_hier_block2 *d_owner;
-    gr_hier_component_map_t d_components;
-    gr_edge_vector_t d_edges;
+    gr_simple_flowgraph_sptr d_fg;
+    gr_endpoint_vector_t d_inputs;
+    gr_endpoint_vector_t d_outputs;
         
     // Private implementation methods
-    void define_component(const std::string &name, gr_basic_block_sptr block);
-    gr_basic_block_sptr lookup_block(const std::string &name);
-    void connect(const std::string &src_name, int src_port, 
-                 const std::string &dst_name, int dst_port);
-    void check_valid_port(gr_io_signature_sptr sig, int port);
-    void check_dst_not_used(const std::string name, int port);
-    void check_type_match(gr_io_signature_sptr src_sig, int src_port,
-                          gr_io_signature_sptr dst_sig, int dst_port);
-    std::string prepend_prefix(const std::string &prefix, const std::string &str);
-    void flatten(gr_simple_flowgraph_sptr sfg, const std::string &prefix = "");
-    void flatten_components(gr_simple_flowgraph_sptr sfg, const std::string &prefix);
-    void flatten_edges(gr_simple_flowgraph_sptr sfg, const std::string &prefix);
-    gr_endpoint match_endpoint(const std::string &name, int port, bool is_input);
-    gr_endpoint resolve_endpoint(const std::string &name, int port, 
-                                 const std::string &prefix, bool is_input);
-    
+    void connect(gr_basic_block_sptr src, int src_port, 
+                 gr_basic_block_sptr dst, int dst_port);
+    void disconnect(gr_basic_block_sptr, int src_port, 
+                    gr_basic_block_sptr, int dst_port);
+    void assign_input(int my_port, int port, gr_basic_block_sptr block);
+    void assign_output(int my_port, int port, gr_basic_block_sptr block);
+    void flatten(gr_simple_flowgraph_sptr sfg);
+    gr_endpoint resolve_port(int port, bool is_input);
+    gr_endpoint resolve_endpoint(const gr_endpoint &endp, bool is_input);
+
 public:
     ~gr_hier_block2_detail();
 };
diff --git a/gnuradio-core/src/lib/runtime/gr_runtime.cc b/gnuradio-core/src/lib/runtime/gr_runtime.cc
index aab8ea5ab..a8b932f21 100644
--- a/gnuradio-core/src/lib/runtime/gr_runtime.cc
+++ b/gnuradio-core/src/lib/runtime/gr_runtime.cc
@@ -1,6 +1,6 @@
 /* -*- c++ -*- */
 /*
- * Copyright 2006 Free Software Foundation, Inc.
+ * Copyright 2006,2007 Free Software Foundation, Inc.
  * 
  * This file is part of GNU Radio
  * 
@@ -34,57 +34,64 @@ static gr_runtime *s_runtime = 0;
 gr_runtime_sptr 
 gr_make_runtime(gr_hier_block2_sptr top_block)
 {
-    return gr_runtime_sptr(new gr_runtime(top_block));
+  return gr_runtime_sptr(new gr_runtime(top_block));
 }
 
 gr_runtime::gr_runtime(gr_hier_block2_sptr top_block)
 {
-    d_impl = new gr_runtime_impl(top_block);
-    s_runtime = this;
+  d_impl = new gr_runtime_impl(top_block);
+  s_runtime = this;
 }
   
 gr_runtime::~gr_runtime()
 {
-    s_runtime = 0; // we don't own this
-    delete d_impl;
+  s_runtime = 0; // we don't own this
+  delete d_impl;
 }
 
 // FIXME: This prevents using more than one gr_runtime instance
 static void 
 runtime_sigint_handler(int signum)
 {
-
-    if (s_runtime)
-        s_runtime->stop();
+  if (s_runtime)
+    s_runtime->stop();
 }
 
 void 
 gr_runtime::start()
 {
-    gr_local_sighandler sigint(SIGINT, runtime_sigint_handler);
+  gr_local_sighandler sigint(SIGINT, runtime_sigint_handler);
 
-    d_impl->start();
+  d_impl->start();
 }
 
 void 
 gr_runtime::stop()
 {
-    d_impl->stop();
+  d_impl->stop();
 }
 
 void 
 gr_runtime::wait()
 {
-    gr_local_sighandler sigint(SIGINT, runtime_sigint_handler);
+  gr_local_sighandler sigint(SIGINT, runtime_sigint_handler);
 
-    d_impl->wait();
+  d_impl->wait();
 }
 
 void 
 gr_runtime::run()
 {
-    gr_local_sighandler sigint(SIGINT, runtime_sigint_handler);
+  gr_local_sighandler sigint(SIGINT, runtime_sigint_handler);
+
+  d_impl->start();
+  d_impl->wait();
+}
+
+void
+gr_runtime::restart()
+{
+  gr_local_sighandler sigint(SIGINT, runtime_sigint_handler);
 
-    d_impl->start();
-    d_impl->wait();
+  d_impl->restart();
 }
diff --git a/gnuradio-core/src/lib/runtime/gr_runtime.h b/gnuradio-core/src/lib/runtime/gr_runtime.h
index fc58da456..5aec6dcf0 100644
--- a/gnuradio-core/src/lib/runtime/gr_runtime.h
+++ b/gnuradio-core/src/lib/runtime/gr_runtime.h
@@ -1,6 +1,6 @@
 /* -*- c++ -*- */
 /*
- * Copyright 2006 Free Software Foundation, Inc.
+ * Copyright 2006,2007 Free Software Foundation, Inc.
  * 
  * This file is part of GNU Radio
  * 
@@ -29,21 +29,57 @@ class gr_runtime_impl;
 
 gr_runtime_sptr gr_make_runtime(gr_hier_block2_sptr top_block);
 
+/*!
+ *\brief Runtime object that controls simple flow graph operation
+ *
+ * This class is instantiated with a top-level gr_hier_block2. The
+ * runtime then flattens the hierarchical block into a gr_simple_flowgraph,
+ * and allows control through start(), stop(), wait(), and run().
+ * 
+ */
 class gr_runtime
 {
 private:
-    gr_runtime(gr_hier_block2_sptr top_block);
-    friend gr_runtime_sptr gr_make_runtime(gr_hier_block2_sptr top_block);
+  gr_runtime(gr_hier_block2_sptr top_block);
+  friend gr_runtime_sptr gr_make_runtime(gr_hier_block2_sptr top_block);
 
-    gr_runtime_impl *d_impl;
+  gr_runtime_impl *d_impl;
     
 public:
-    ~gr_runtime();
+  ~gr_runtime();
+
+  /*!
+   * Start the flow graph.  Creates an undetached scheduler thread for
+   * each flow graph partition. Returns to caller once created.
+   */
+  void start();
+  
+  /*!
+   * Stop a running flow graph.  Tells each created scheduler thread
+   * to exit, then returns to caller.
+   */
+  void stop();
+
+  /*!
+   * Wait for a stopped flow graph to complete.  Joins each completed
+   * thread.
+   */
+  void wait();
+
+  /*!
+   * Calls start(), then wait().  Used to run a flow graph that will stop
+   * on its own, or to run a flow graph indefinitely until SIGTERM is
+   * received().
+   */
+  void run();
 
-    void start();
-    void stop();
-    void wait();
-    void run();
+  /*!
+   * Restart a running flow graph, after topology changes have
+   * been made to its top_block (or children). Causes each created 
+   * scheduler thread to end, recalculates the flow graph, and 
+   * recreates new threads (possibly a different number from before.)
+   */
+  void restart();
 };
 
 #endif /* INCLUDED_GR_RUNTIME_H */
diff --git a/gnuradio-core/src/lib/runtime/gr_runtime.i b/gnuradio-core/src/lib/runtime/gr_runtime.i
index 3a8b7e0b6..10e757baa 100644
--- a/gnuradio-core/src/lib/runtime/gr_runtime.i
+++ b/gnuradio-core/src/lib/runtime/gr_runtime.i
@@ -1,6 +1,6 @@
 /* -*- c++ -*- */
 /*
- * Copyright 2004,2006 Free Software Foundation, Inc.
+ * Copyright 2004,2006,2007 Free Software Foundation, Inc.
  * 
  * This file is part of GNU Radio
  * 
@@ -36,6 +36,7 @@ public:
     void start() throw (std::runtime_error);
     void stop() throw (std::runtime_error);
     void wait() throw (std::runtime_error);
+    void restart() throw (std::runtime_error);
 };
 
 %{
@@ -72,4 +73,10 @@ void runtime_wait_unlocked(gr_runtime_sptr r) throw (std::runtime_error)
     r->wait();
 }
 
+void runtime_restart_unlocked(gr_runtime_sptr r) throw (std::runtime_error) 
+{
+    ensure_py_gil_state2 _lock;
+    r->restart();
+}
+
 %}
diff --git a/gnuradio-core/src/lib/runtime/gr_runtime_impl.cc b/gnuradio-core/src/lib/runtime/gr_runtime_impl.cc
index f8d65261e..5cd75f3ce 100644
--- a/gnuradio-core/src/lib/runtime/gr_runtime_impl.cc
+++ b/gnuradio-core/src/lib/runtime/gr_runtime_impl.cc
@@ -36,8 +36,6 @@
 #include <stdexcept>
 #include <iostream>
 
-#define GR_RUNTIME_IMPL_DEBUG 0
-
 gr_runtime_impl::gr_runtime_impl(gr_hier_block2_sptr top_block) 
   : d_running(false),
     d_top_block(top_block),
@@ -52,56 +50,82 @@ gr_runtime_impl::~gr_runtime_impl()
 void
 gr_runtime_impl::start()
 {
-    if (d_running)
-        throw std::runtime_error("already running");
-    else
-        d_running = true;
-
-    d_sfg->d_detail->reset();
-    d_top_block->d_detail->flatten(d_sfg);
-    d_sfg->d_detail->validate();
-    d_sfg->d_detail->setup_connections();
-
-    d_graphs = d_sfg->d_detail->partition();
-    if (GR_RUNTIME_IMPL_DEBUG)
-        std::cout << "Flow graph has " << d_graphs.size()
-                  << " sub-graphs." << std::endl;
-
-    d_threads.clear();
-    for (std::vector<gr_block_vector_t>::iterator p = d_graphs.begin();
-         p != d_graphs.end(); p++) {
-        gr_scheduler_thread *thread = new gr_scheduler_thread(*p);
-        thread->start();
-        d_threads.push_back(thread);
-    }
+  if (d_running)
+    throw std::runtime_error("already running");
+  else
+    d_running = true;
+
+  // Create new simple flow graph by flattening hierarchical block
+  d_sfg->d_detail->reset();
+  d_top_block->d_detail->flatten(d_sfg);
+
+  // Validate new simple flow graph and wire it up
+  d_sfg->d_detail->validate();
+  d_sfg->d_detail->setup_connections();
+
+  // Execute scheduler threads
+  start_threads();
+}
+
+void
+gr_runtime_impl::start_threads()
+{
+  d_graphs = d_sfg->d_detail->partition();
+  d_threads.clear();
+  for (std::vector<gr_block_vector_t>::iterator p = d_graphs.begin();
+       p != d_graphs.end(); p++) {
+    gr_scheduler_thread *thread = new gr_scheduler_thread(*p);
+    thread->start();
+    d_threads.push_back(thread);
+  }
 }
 
 void
 gr_runtime_impl::stop()
 {
-    if (!d_running)
-        throw std::runtime_error("not running");
+  if (!d_running)
+    throw std::runtime_error("not running");
 
-    for (gr_scheduler_thread_viter_t p = d_threads.begin(); p != d_threads.end(); p++)
-        (*p)->stop(); 
+  for (gr_scheduler_thread_viter_t p = d_threads.begin(); p != d_threads.end(); p++)
+    (*p)->stop(); 
 
-    d_running = false;
+  d_running = false;
 }
 
 void
 gr_runtime_impl::wait()
 {
-    void *dummy_status; // don't ever dereference this
+  void *dummy_status; // don't ever dereference this
+
+  for (gr_scheduler_thread_viter_t p = d_threads.begin(); p != d_threads.end(); p++) {
+    (*p)->join(&dummy_status); // pthreads will self-delete, so pointer is now dead
+    (*p) = 0; // FIXME: switch to stl::list and actually remove from container
+  }
+}
 
-    for (gr_scheduler_thread_viter_t p = d_threads.begin(); p != d_threads.end(); p++) {
-        (*p)->join(&dummy_status); // pthreads will self-delete, so pointer is now dead
-        (*p) = 0; // FIXME: switch to stl::list and actually remove from container
-    }
+void
+gr_runtime_impl::restart()
+{
+  if (!d_running)
+    throw std::runtime_error("not running");
+
+  // Stop scheduler threads and wait for completion
+  stop();
+  wait();
+  
+  // Create new simple flow graph 
+  gr_simple_flowgraph_sptr new_sfg = gr_make_simple_flowgraph();
+  d_top_block->d_detail->flatten(new_sfg);
+  new_sfg->validate();
+  new_sfg->d_detail->merge_connections(d_sfg);
+  // d_sfg = new_sfg;
+
+  start_threads();
 }
 
 gr_scheduler_thread::gr_scheduler_thread(gr_block_vector_t graph) :
-    omni_thread(NULL, PRIORITY_NORMAL),
-    d_sts(gr_make_single_threaded_scheduler(graph))
+  omni_thread(NULL, PRIORITY_NORMAL),
+  d_sts(gr_make_single_threaded_scheduler(graph))
 {
 }
 
@@ -111,28 +135,29 @@ gr_scheduler_thread::~gr_scheduler_thread()
 
 void gr_scheduler_thread::start()
 {
-    start_undetached();
+  start_undetached();
 }
 
 void *
 gr_scheduler_thread::run_undetached(void *arg)
 {
-    // First code to run in new thread context
+  // First code to run in new thread context
 
-    // Mask off SIGINT in this thread to gaurantee mainline thread gets signal
+  // Mask off SIGINT in this thread to gaurantee mainline thread gets signal
 #ifdef HAVE_SIGPROCMASK
-    sigset_t old_set;
-    sigset_t new_set;
-    sigemptyset(&new_set);
-    sigaddset(&new_set, SIGINT);
-    sigprocmask(SIG_BLOCK, &new_set, &old_set);
+  sigset_t old_set;
+  sigset_t new_set;
+  sigemptyset(&new_set);
+  sigaddset(&new_set, SIGINT);
+  sigprocmask(SIG_BLOCK, &new_set, &old_set);
 #endif
-    // Run the single-threaded scheduler
-    d_sts->run();
-    return 0;
+  // Run the single-threaded scheduler
+  d_sts->run();
+  return 0;
 }
 
-void gr_scheduler_thread::stop()
+void
+gr_scheduler_thread::stop()
 {
-    d_sts->stop();
+  d_sts->stop();
 }
diff --git a/gnuradio-core/src/lib/runtime/gr_runtime_impl.h b/gnuradio-core/src/lib/runtime/gr_runtime_impl.h
index e69446719..bb2a08334 100644
--- a/gnuradio-core/src/lib/runtime/gr_runtime_impl.h
+++ b/gnuradio-core/src/lib/runtime/gr_runtime_impl.h
@@ -1,6 +1,6 @@
 /* -*- c++ -*- */
 /*
- * Copyright 2006 Free Software Foundation, Inc.
+ * Copyright 2006,2007 Free Software Foundation, Inc.
  * 
  * This file is part of GNU Radio
  * 
@@ -33,38 +33,56 @@ class gr_scheduler_thread;
 typedef std::vector<gr_scheduler_thread *> gr_scheduler_thread_vector_t;
 typedef gr_scheduler_thread_vector_t::iterator gr_scheduler_thread_viter_t;
 
+/*!
+ *\brief A single thread of execution for the scheduler
+ *
+ * This class implements a single thread that runs undetached, and
+ * invokes the single-threaded block scheduler.  The runtime makes
+ * one of these for each distinct partition of a flowgraph and runs
+ * them in parallel.
+ *
+ */
 class gr_scheduler_thread : public omni_thread
 {
 private:
-    gr_single_threaded_scheduler_sptr d_sts;    
+  gr_single_threaded_scheduler_sptr d_sts;    
 
 public:
-    gr_scheduler_thread(gr_block_vector_t graph);
-    ~gr_scheduler_thread();
+  gr_scheduler_thread(gr_block_vector_t graph);
+  ~gr_scheduler_thread();
 
-    virtual void *run_undetached(void *arg);
-    void start();
-    void stop();
+  virtual void *run_undetached(void *arg);
+  void start();
+  void stop();
 };
 
+/*!
+ *\brief Implementation details of gr_runtime
+ *
+ * The actual implementation of gr_runtime. Separate class allows
+ * decoupling of changes from dependent classes.
+ *
+ */
 class gr_runtime_impl
 {
 private:
-    gr_runtime_impl(gr_hier_block2_sptr top_block);
-    friend class gr_runtime;
+  gr_runtime_impl(gr_hier_block2_sptr top_block);
+  friend class gr_runtime;
     
-    bool                           d_running;
-    gr_hier_block2_sptr            d_top_block;
-    gr_simple_flowgraph_sptr       d_sfg;
-    std::vector<gr_block_vector_t> d_graphs;
-    gr_scheduler_thread_vector_t   d_threads;
+  bool                           d_running;
+  gr_hier_block2_sptr            d_top_block;
+  gr_simple_flowgraph_sptr       d_sfg;
+  std::vector<gr_block_vector_t> d_graphs;
+  gr_scheduler_thread_vector_t   d_threads;
             
-    void start();
-    void stop();
-    void wait();
-    
+  void start();
+  void start_threads();
+  void stop();
+  void wait();
+  void restart();
+
 public:
-    ~gr_runtime_impl();
+  ~gr_runtime_impl();
 
 };
 
diff --git a/gnuradio-core/src/lib/runtime/gr_simple_flowgraph.cc b/gnuradio-core/src/lib/runtime/gr_simple_flowgraph.cc
index 21aeb587c..780d51d78 100644
--- a/gnuradio-core/src/lib/runtime/gr_simple_flowgraph.cc
+++ b/gnuradio-core/src/lib/runtime/gr_simple_flowgraph.cc
@@ -28,11 +28,9 @@
 #include <gr_simple_flowgraph_detail.h>
 #include <iostream>
 
-#define GR_SIMPLE_FLOWGRAPH_DEBUG 0
-
 gr_simple_flowgraph_sptr gr_make_simple_flowgraph()
 {
-    return gr_simple_flowgraph_sptr(new gr_simple_flowgraph());
+  return gr_simple_flowgraph_sptr(new gr_simple_flowgraph());
 }
 
 gr_simple_flowgraph::gr_simple_flowgraph() :
@@ -42,26 +40,31 @@ d_detail(new gr_simple_flowgraph_detail())
   
 gr_simple_flowgraph::~gr_simple_flowgraph()
 {
-    delete d_detail;
+  delete d_detail;
+}
+
+void
+gr_simple_flowgraph::connect(gr_basic_block_sptr src_block, int src_port,
+			     gr_basic_block_sptr dst_block, int dst_port)
+{
+  d_detail->connect(gr_endpoint(src_block, src_port), gr_endpoint(dst_block, dst_port));
 }
 
 void
-gr_simple_flowgraph::define_component(const std::string &name, gr_block_sptr block)
+gr_simple_flowgraph::connect(const gr_endpoint &src, const gr_endpoint &dst)
 {
-    if (GR_SIMPLE_FLOWGRAPH_DEBUG)
-        std::cout << "Defining block " << block << " as " << name << std::endl;
-    d_detail->define_component(name, block);
+  d_detail->connect(src, dst);
 }
 
 void
-gr_simple_flowgraph::connect(const std::string &src_name, int src_port,
-                             const std::string &dst_name, int dst_port)
+gr_simple_flowgraph::disconnect(gr_basic_block_sptr src_block, int src_port,
+				gr_basic_block_sptr dst_block, int dst_port)
 {
-    d_detail->connect(src_name, src_port, dst_name, dst_port);
+  d_detail->disconnect(gr_endpoint(src_block, src_port), gr_endpoint(dst_block, dst_port));
 }
 
 void
 gr_simple_flowgraph::validate()
 {
-    d_detail->validate();
+  d_detail->validate();
 }
diff --git a/gnuradio-core/src/lib/runtime/gr_simple_flowgraph.h b/gnuradio-core/src/lib/runtime/gr_simple_flowgraph.h
index ca2c505e5..a22e558ff 100644
--- a/gnuradio-core/src/lib/runtime/gr_simple_flowgraph.h
+++ b/gnuradio-core/src/lib/runtime/gr_simple_flowgraph.h
@@ -1,6 +1,6 @@
 /* -*- c++ -*- */
 /*
- * Copyright 2006 Free Software Foundation, Inc.
+ * Copyright 2006,2007 Free Software Foundation, Inc.
  * 
  * This file is part of GNU Radio
  * 
@@ -31,22 +31,52 @@ gr_simple_flowgraph_sptr gr_make_simple_flowgraph();
 
 class gr_simple_flowgraph_detail;
 
+class gr_endpoint
+{
+private:
+  friend class gr_hier_block2_detail;
+  gr_basic_block_sptr d_block;
+  int d_port;
+
+public:
+  gr_endpoint() : d_block(), d_port(0) { } // Internal use only
+  gr_endpoint(gr_basic_block_sptr block, int port) { d_block = block; d_port = port; }
+  gr_basic_block_sptr block() const { return d_block; }
+  int port() const { return d_port; }
+};    
+
+typedef std::vector<gr_endpoint> gr_endpoint_vector_t;
+
+/*!
+ *\brief Class representing a low-level, "flattened" flow graph
+ *
+ * This class holds the results of the call to gr.hier_block2.flatten(),
+ * which is a graph that has only the connected blocks and edges of
+ * the original hier_block2, with all the hierarchy removed.
+ *
+ * While this class is exported to Python via SWIG for ease of QA
+ * testing, it is not used by application developers, and there is
+ * no way to feed this to a gr.runtime() instance.
+ */
 class gr_simple_flowgraph
 {
 private:
-    friend class gr_runtime_impl;
-    friend gr_simple_flowgraph_sptr gr_make_simple_flowgraph();
-    gr_simple_flowgraph();
+  friend class gr_runtime_impl;
+  friend class gr_hier_block2_detail;
+  friend gr_simple_flowgraph_sptr gr_make_simple_flowgraph();
+  gr_simple_flowgraph();
 
-    gr_simple_flowgraph_detail *d_detail;
+  gr_simple_flowgraph_detail *d_detail;
             
 public:
-    ~gr_simple_flowgraph();
+  ~gr_simple_flowgraph();
 
-    void define_component(const std::string &name, gr_block_sptr block);    
-    void connect(const std::string &src, int src_port, 
-                 const std::string &dst, int dst_port);
-    void validate();
+  void connect(gr_basic_block_sptr src_block, int src_port,
+	       gr_basic_block_sptr dst_block, int dst_port);
+  void connect(const gr_endpoint &src, const gr_endpoint &dst);
+  void disconnect(gr_basic_block_sptr src_block, int src_port,
+		  gr_basic_block_sptr dst_block, int dst_port);
+  void validate();
 };
 
 #endif /* INCLUDED_GR_SIMPLE_FLOWGRAPH_H */
diff --git a/gnuradio-core/src/lib/runtime/gr_simple_flowgraph.i b/gnuradio-core/src/lib/runtime/gr_simple_flowgraph.i
deleted file mode 100644
index c3654fe50..000000000
--- a/gnuradio-core/src/lib/runtime/gr_simple_flowgraph.i
+++ /dev/null
@@ -1,45 +0,0 @@
-/* -*- c++ -*- */
-/*
- * Copyright 2006 Free Software Foundation, Inc.
- * 
- * This file is part of GNU Radio
- * 
- * GNU Radio is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2, or (at your option)
- * any later version.
- * 
- * GNU Radio is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- * 
- * You should have received a copy of the GNU General Public License
- * along with GNU Radio; see the file COPYING.  If not, write to
- * the Free Software Foundation, Inc., 51 Franklin Street,
- * Boston, MA 02110-1301, USA.
- */
-
-class gr_simple_flowgraph;
-typedef boost::shared_ptr<gr_simple_flowgraph> gr_simple_flowgraph_sptr;
-%template(gr_simple_flowgraph_sptr) boost::shared_ptr<gr_simple_flowgraph>;
-%rename(simple_flowgraph) gr_make_simple_flowgraph;
-%ignore gr_simple_flowgraph;
-
-gr_simple_flowgraph_sptr gr_make_simple_flowgraph();
-
-class gr_simple_flowgraph 
-{
-private:
-    gr_simple_flowgraph();
-
-public:
-    ~gr_simple_flowgraph();
-    void define_component(const std::string name, gr_block_sptr block)
-        throw (std::invalid_argument);
-    void connect(const std::string &src, int src_port,
-                 const std::string &dst, int dst_port)
-        throw (std::invalid_argument);
-    void validate()
-        throw (std::runtime_error);
-};
diff --git a/gnuradio-core/src/lib/runtime/gr_simple_flowgraph_detail.cc b/gnuradio-core/src/lib/runtime/gr_simple_flowgraph_detail.cc
index 0c9c9b707..13d23efe5 100644
--- a/gnuradio-core/src/lib/runtime/gr_simple_flowgraph_detail.cc
+++ b/gnuradio-core/src/lib/runtime/gr_simple_flowgraph_detail.cc
@@ -1,6 +1,6 @@
 /* -*- c++ -*- */
 /*
- * Copyright 2006 Free Software Foundation, Inc.
+ * Copyright 2006,2007 Free Software Foundation, Inc.
  *
  * This file is part of GNU Radio
  *
@@ -32,31 +32,16 @@
 #include <iostream>
 #include <stdexcept>
 
-#define GR_SIMPLE_FLOWGRAPH_DETAIL_DEBUG 0
-
 gr_edge_sptr
-gr_make_edge(const std::string &src_name, int src_port,
-	     const std::string &dst_name, int dst_port)
-{
-    return gr_edge_sptr(new gr_edge(src_name, src_port, dst_name, dst_port));
-}
-
-gr_edge::gr_edge(const std::string &src_name, int src_port, const std::string &dst_name, int dst_port)
-  : d_src(src_name, src_port),
-    d_dst(dst_name, dst_port)
+gr_make_edge(const gr_endpoint &src, const gr_endpoint &dst)
 {
+  return gr_edge_sptr(new gr_edge(src, dst));
 }
 
 gr_edge::~gr_edge()
 {
 }
 
-gr_simple_flowgraph_detail::gr_simple_flowgraph_detail() :
-d_components(),
-d_edges()
-{
-}
-
 gr_simple_flowgraph_detail::~gr_simple_flowgraph_detail()
 {
 }
@@ -64,498 +49,435 @@ gr_simple_flowgraph_detail::~gr_simple_flowgraph_detail()
 void
 gr_simple_flowgraph_detail::reset()
 {
-    // Boost shared pointers will deallocate as needed
-    d_edges.clear();
-    d_components.clear();
-}
-
-gr_block_sptr
-gr_simple_flowgraph_detail::lookup_block(const std::string &name)
-{
-    gr_component_miter_t p = d_components.find(name);
-    if (p != d_components.end())
-        return p->second;
-    else
-        return gr_block_sptr();
-}
-
-std::string
-gr_simple_flowgraph_detail::lookup_name(gr_block_sptr block)
-{
-    for (gr_component_miter_t p = d_components.begin(); p != d_components.end(); p++) {
-        if (p->second == block)
-            return p->first;
-    }
-
-    return std::string(""); // Not found
+  // Boost shared pointers will deallocate as needed
+  d_edges.clear();
+  d_blocks.clear();
 }
 
 void
-gr_simple_flowgraph_detail::define_component(const std::string &name, gr_block_sptr block)
+gr_simple_flowgraph_detail::connect(const gr_endpoint &src, const gr_endpoint &dst)
 {
-    if (!block)
-        throw std::invalid_argument("null block passed");
-
-    if (!lookup_block(name))
-        d_components[name] = block;
-    else
-        throw std::invalid_argument("name already in use");
+  check_valid_port(src.block()->output_signature(), src.port());
+  check_valid_port(dst.block()->input_signature(), dst.port());
+  check_dst_not_used(dst);
+  check_type_match(src, dst);
+  d_edges.push_back(gr_make_edge(src,dst));
 }
 
 void
-gr_simple_flowgraph_detail::connect(const std::string &src_name, int src_port,
-                                    const std::string &dst_name, int dst_port)
+gr_simple_flowgraph_detail::disconnect(const gr_endpoint &src, const gr_endpoint &dst)
 {
-    gr_block_sptr src_block = lookup_block(src_name);
-    gr_block_sptr dst_block = lookup_block(dst_name);
-
-    if (GR_SIMPLE_FLOWGRAPH_DETAIL_DEBUG)
-        std::cout << "Connecting " << src_name << ":" << src_port << "->"
-                  << dst_name << ":" << dst_port << std::endl;
-
-    if (!src_block)
-        throw std::invalid_argument("unknown src name");
-    if (!dst_block)
-        throw std::invalid_argument("unknown dst name");
-
-    check_valid_port(src_block->output_signature(), src_port);
-    check_valid_port(dst_block->input_signature(), dst_port);
-    check_dst_not_used(dst_name, dst_port);
-    check_type_match(src_block, src_port, dst_block, dst_port);
+  for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++) {
+    if (src.block() == (*p)->src().block() && src.port() == (*p)->src().port() && 
+	dst.block() == (*p)->dst().block() && dst.port() == (*p)->dst().port()) {
+      d_edges.erase(p);
+      return;
+    }
+  }
 
-    d_edges.push_back(gr_make_edge(src_name, src_port, dst_name, dst_port));
+  throw std::invalid_argument("edge to disconnect not found");
 }
 
 void
 gr_simple_flowgraph_detail::check_valid_port(gr_io_signature_sptr sig, int port)
 {
-    if (port < 0)
-        throw std::invalid_argument("negative port number");
-    if (sig->max_streams() >= 0 && port >= sig->max_streams())
-        throw std::invalid_argument("port number exceeds max");
+  if (port < 0)
+    throw std::invalid_argument("negative port number");
+  if (sig->max_streams() >= 0 && port >= sig->max_streams())
+    throw std::invalid_argument("port number exceeds max");
 }
 
 void
-gr_simple_flowgraph_detail::check_dst_not_used(const std::string &name, int port)
+gr_simple_flowgraph_detail::check_dst_not_used(const gr_endpoint &dst)
 {
-    for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++)
-	if ((*p)->dst_name() == name && (*p)->dst_port() == port)
-	    throw std::invalid_argument("dst already in use");
+  for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++)
+    if ((*p)->dst().block() == dst.block() &&
+        (*p)->dst().port() == dst.port())
+      throw std::invalid_argument("dst already in use");
 }
 
 void
-gr_simple_flowgraph_detail::check_type_match(gr_block_sptr src_block, int src_port,
-                                             gr_block_sptr dst_block, int dst_port)
+gr_simple_flowgraph_detail::check_type_match(const gr_endpoint &src, const gr_endpoint &dst)
 {
-    int src_size = src_block->output_signature()->sizeof_stream_item(src_port);
-    int dst_size = dst_block->input_signature()->sizeof_stream_item(dst_port);
+  int src_size = src.block()->output_signature()->sizeof_stream_item(src.port());
+  int dst_size = dst.block()->input_signature()->sizeof_stream_item(dst.port());
 
-    if (src_size != dst_size)
-        throw std::invalid_argument("type size mismatch");
+  if (src_size != dst_size)
+    throw std::invalid_argument("type size mismatch while attempting to connect");
 }
 
 void
 gr_simple_flowgraph_detail::validate()
 {
-    for (gr_component_miter_t p = d_components.begin(); p != d_components.end(); p++) {
-    	std::vector<int> used_ports;
-    	int ninputs, noutputs;
+  d_blocks = calc_used_blocks();
 
-        used_ports = calc_used_ports(p->first, true); // inputs
-    	ninputs = used_ports.size();
-    	check_contiguity(p->second, used_ports, true); // inputs
+  for (gr_basic_block_viter_t p = d_blocks.begin(); p != d_blocks.end(); p++) {
+    std::vector<int> used_ports;
+    int ninputs, noutputs;
 
-    	used_ports = calc_used_ports(p->first, false); // outputs
-    	noutputs = used_ports.size();
-    	check_contiguity(p->second, used_ports, false); // outputs
+    used_ports = calc_used_ports(*p, true); // inputs
+    ninputs = used_ports.size();
+    check_contiguity(*p, used_ports, true); // inputs
 
-    	if (!(p->second->check_topology(ninputs, noutputs)))
-    	    throw std::runtime_error("check topology failed");
-    }
+    used_ports = calc_used_ports(*p, false); // outputs
+    noutputs = used_ports.size();
+    check_contiguity(*p, used_ports, false); // outputs
+
+    if (!((*p)->check_topology(ninputs, noutputs)))
+      throw std::runtime_error("check topology failed");
+  }
 }
 
 std::vector<int>
-gr_simple_flowgraph_detail::calc_used_ports(const std::string &name, bool check_inputs)
+gr_simple_flowgraph_detail::calc_used_ports(gr_basic_block_sptr block, bool check_inputs)
 {
-    if (GR_SIMPLE_FLOWGRAPH_DETAIL_DEBUG)
-        std::cout << "Calculating used " << (check_inputs ? "input " : "output ")
-                  << "ports...";
-
-    std::vector<int> tmp, result;
-    std::insert_iterator<std::vector<int> > inserter(result, result.begin());
-
-    gr_edge_vector_t edges = calc_connections(name, check_inputs);
-
-    for (gr_edge_viter_t p = edges.begin(); p != edges.end(); p++) {
-        if (check_inputs == true)
-            tmp.push_back((*p)->dst_port());
-        else
-            tmp.push_back((*p)->src_port());
-    }
-
-    // remove duplicates
-    std::sort(tmp.begin(), tmp.end());
-    std::unique_copy(tmp.begin(), tmp.end(), inserter);
+  std::vector<int> tmp, result;
+  std::insert_iterator<std::vector<int> > inserter(result, result.begin());
 
-    if (GR_SIMPLE_FLOWGRAPH_DETAIL_DEBUG)
-        std::cout << result.size() << std::endl;
+  gr_edge_vector_t edges = calc_connections(block, check_inputs);
+  for (gr_edge_viter_t p = edges.begin(); p != edges.end(); p++) {
+    if (check_inputs == true)
+      tmp.push_back((*p)->dst().port());
+    else
+      tmp.push_back((*p)->src().port());
+  }
 
-    return result;
+  // remove duplicates
+  std::sort(tmp.begin(), tmp.end());
+  std::unique_copy(tmp.begin(), tmp.end(), inserter);
+  return result;
 }
 
 gr_edge_vector_t
-gr_simple_flowgraph_detail::calc_connections(const std::string &name, bool check_inputs)
+gr_simple_flowgraph_detail::calc_connections(gr_basic_block_sptr block, bool check_inputs)
 {
-    gr_edge_vector_t result;
-
-    for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++) {
-        if (check_inputs) {
-            if ((*p)->dst_name() == name)
-                result.push_back(*p);
-        }
-        else {
-            if ((*p)->src_name() == name)
-                result.push_back(*p);
-        }
+  gr_edge_vector_t result;
+
+  for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++) {
+    if (check_inputs) {
+      if ((*p)->dst().block() == block)
+	result.push_back(*p);
     }
+    else {
+      if ((*p)->src().block() == block)
+	result.push_back(*p);
+    }
+  }
 
-    return result;    // assumes no duplicates
+  return result;    // assumes no duplicates
 }
 
 void
-gr_simple_flowgraph_detail::check_contiguity(gr_block_sptr block,
+gr_simple_flowgraph_detail::check_contiguity(gr_basic_block_sptr block,
                                              const std::vector<int> &used_ports,
                                              bool check_inputs)
 {
-    if (GR_SIMPLE_FLOWGRAPH_DETAIL_DEBUG)
-        std::cout << "Checking " << (check_inputs ? "input " : "output ")
-                  << "contiguity...";
-
-    gr_io_signature_sptr sig =
-        check_inputs ? block->input_signature() : block->output_signature();
-
-    int nports = used_ports.size();
-    int min_ports = sig->min_streams();
-
-    if (nports == 0) {
-        if (min_ports == 0) {
-            if (GR_SIMPLE_FLOWGRAPH_DETAIL_DEBUG)
-                std::cout << "ok." << std::endl;
-            return;
-        }
-        else {
-            if (GR_SIMPLE_FLOWGRAPH_DETAIL_DEBUG)
-                std::cout << "needs " << min_ports << ", only has "
-                          << nports << std::endl;
-
-            throw std::runtime_error("insufficient ports");
-        }
-    }
+  gr_io_signature_sptr sig =
+    check_inputs ? block->input_signature() : block->output_signature();
 
-    if (used_ports[nports-1]+1 != nports) {
-        for (int i = 0; i < nports; i++) {
-            if (used_ports[i] != i) {
-                if (GR_SIMPLE_FLOWGRAPH_DETAIL_DEBUG)
-	                std::cout << "missing " << (check_inputs ? "input ":"output ")
-                              << i << std::endl;
+  int nports = used_ports.size();
+  int min_ports = sig->min_streams();
 
-                throw std::runtime_error("missing input assignment");
-	        }
-	    }
-    }
-
-    if (GR_SIMPLE_FLOWGRAPH_DETAIL_DEBUG)
-        std::cout << "ok." << std::endl;
+  if (nports == 0) {
+    if (min_ports == 0)
+      return;
+    else
+      throw std::runtime_error("insufficient ports");
+  }
+
+  if (used_ports[nports-1]+1 != nports) {
+    for (int i = 0; i < nports; i++)
+      if (used_ports[i] != i)
+	throw std::runtime_error("missing input assignment");
+  }
 }
 
 void
 gr_simple_flowgraph_detail::setup_connections()
 {
-    // Assign block details to component blocks
-    for (gr_component_miter_t p = d_components.begin(); p != d_components.end(); p++) {
-        if (GR_SIMPLE_FLOWGRAPH_DETAIL_DEBUG)
-            std::cout << "Allocating output buffers for " << p->first << "..." << std::endl;
-
-        int ninputs = calc_used_ports(p->first, true).size();
-        int noutputs = calc_used_ports(p->first, false).size();
-        gr_block_detail_sptr detail = gr_make_block_detail(ninputs, noutputs);
-        for (int i = 0; i < noutputs; i++)
-            detail->set_output(i, allocate_buffer(p->first, i));
-        p->second->set_detail(detail);
-    }
-
-    // Connect inputs to outputs for each block
-    for(gr_component_miter_t p = d_components.begin(); p != d_components.end(); p++) {
-        // Get its detail and edges that feed into it
-        gr_block_detail_sptr detail = p->second->detail();
-        gr_edge_vector_t in_edges = calc_upstream_edges(p->first);
-
-        if (GR_SIMPLE_FLOWGRAPH_DETAIL_DEBUG)
-	        if (in_edges.size() > 0)
-        	    std::cout << "Connecting inputs to " << p->first << "..." << std::endl;
-
-        // For each edge that feeds into it
-        for (gr_edge_viter_t e = in_edges.begin(); e != in_edges.end(); e++) {
-            // Set the input buffer on the destination port to the output
-            // buffer on the source port
-            int dst_port = (*e)->dst_port();
-            int src_port = (*e)->src_port();
-            gr_block_sptr src_block = lookup_block((*e)->src_name());
-            gr_buffer_sptr src_buffer = src_block->detail()->output(src_port);
-
-            if (GR_SIMPLE_FLOWGRAPH_DETAIL_DEBUG)
-                std::cout << "Setting input on " << (*e)->dst_name()
-                          << ":" << dst_port << std::endl;
-
-            detail->set_input(dst_port, gr_buffer_add_reader(src_buffer, p->second->history()-1));
-        }
+  // Assign block details to blocks
+  for (gr_basic_block_viter_t p = d_blocks.begin(); p != d_blocks.end(); p++) {
+    int ninputs = calc_used_ports(*p, true).size();
+    int noutputs = calc_used_ports(*p, false).size();
+    gr_block_detail_sptr detail = gr_make_block_detail(ninputs, noutputs);
+    for (int i = 0; i < noutputs; i++)
+      detail->set_output(i, allocate_buffer(*p, i));
+
+    boost::dynamic_pointer_cast<gr_block, gr_basic_block>(*p)->set_detail(detail);
+  }
+
+  // Connect inputs to outputs for each block
+  for(gr_basic_block_viter_t p = d_blocks.begin(); p != d_blocks.end(); p++) {
+    gr_block_sptr grblock(boost::dynamic_pointer_cast<gr_block, gr_basic_block>(*p));
+    if (!grblock)
+      throw std::runtime_error("setup_connections found non-gr_block");
+
+    // Get its detail and edges that feed into it
+    gr_block_detail_sptr detail = grblock->detail();
+    gr_edge_vector_t in_edges = calc_upstream_edges(*p);
+
+    // For each edge that feeds into it
+    for (gr_edge_viter_t e = in_edges.begin(); e != in_edges.end(); e++) {
+      // Set the input reader on the destination port to the output
+      // buffer on the source port
+      int dst_port = (*e)->dst().port();
+      int src_port = (*e)->src().port();
+      gr_basic_block_sptr src_block = (*e)->src().block();
+      gr_block_sptr src_grblock(boost::dynamic_pointer_cast<gr_block, gr_basic_block>(src_block));
+      if (!grblock)
+	throw std::runtime_error("setup_connections found non-gr_block");
+      gr_buffer_sptr src_buffer = src_grblock->detail()->output(src_port);
+
+      detail->set_input(dst_port, gr_buffer_add_reader(src_buffer, grblock->history()-1));
     }
+  }
 }
 
 gr_buffer_sptr
-gr_simple_flowgraph_detail::allocate_buffer(const std::string &name, int port)
+gr_simple_flowgraph_detail::allocate_buffer(gr_basic_block_sptr block, int port)
 {
-    gr_block_sptr block = lookup_block(name);
-    int item_size = block->output_signature()->sizeof_stream_item(port);
-    int nitems = s_fixed_buffer_size/item_size;
-
-    // Make sure there are at least twice the output_multiple no. of items
-    if (nitems < 2*block->output_multiple())	// Note: this means output_multiple()
-        nitems = 2*block->output_multiple();	// can't be changed by block dynamically
-
-    // If any downstream blocks are decimators and/or have a large output_multiple,
-    // ensure we have a buffer at least twice their decimation factor*output_multiple
-    gr_block_vector_t blocks = calc_downstream_blocks(name, port);
-    for (gr_block_viter_t p = blocks.begin(); p != blocks.end(); p++) {
-        int decimation = (int)(1.0/(*p)->relative_rate());
-        int multiple   = (*p)->output_multiple();
-        int history    = (*p)->history();
-        nitems = std::max(nitems, 2*(decimation*multiple+history));
-    }
-
-    if (GR_SIMPLE_FLOWGRAPH_DETAIL_DEBUG)
-        std::cout << "Allocating buffer for port " << port << " with "
-                  << nitems << " items of size " << item_size << std::endl;
-
-    return gr_make_buffer(nitems, item_size);
+  gr_block_sptr grblock(boost::dynamic_pointer_cast<gr_block, gr_basic_block>(block));
+  if (!grblock)
+    throw std::runtime_error("allocate_buffer found non-gr_block");
+  int item_size = block->output_signature()->sizeof_stream_item(port);
+  int nitems = s_fixed_buffer_size/item_size;
+
+  // Make sure there are at least twice the output_multiple no. of items
+  if (nitems < 2*grblock->output_multiple())	// Note: this means output_multiple()
+    nitems = 2*grblock->output_multiple();	// can't be changed by block dynamically
+
+  // If any downstream blocks are decimators and/or have a large output_multiple,
+  // ensure we have a buffer at least twice their decimation factor*output_multiple
+  gr_basic_block_vector_t blocks = calc_downstream_blocks(block, port);
+  for (gr_basic_block_viter_t p = blocks.begin(); p != blocks.end(); p++) {
+    gr_block_sptr dgrblock(boost::dynamic_pointer_cast<gr_block, gr_basic_block>(*p));
+      if (!dgrblock)
+	throw std::runtime_error("allocate_buffer found non-gr_block");
+    int decimation = (int)(1.0/dgrblock->relative_rate());
+    int multiple   = dgrblock->output_multiple();
+    int history    = dgrblock->history();
+    nitems = std::max(nitems, 2*(decimation*multiple+history));
+  }
+
+  return gr_make_buffer(nitems, item_size);
 }
 
-gr_block_vector_t
-gr_simple_flowgraph_detail::calc_downstream_blocks(const std::string &name, int port)
+gr_basic_block_vector_t
+gr_simple_flowgraph_detail::calc_downstream_blocks(gr_basic_block_sptr block, int port)
 {
-    gr_block_vector_t tmp, result;
-    std::insert_iterator<gr_block_vector_t> inserter(result, result.begin());
+  gr_basic_block_vector_t tmp, result;
+  std::insert_iterator<gr_basic_block_vector_t> inserter(result, result.begin());
 
-    for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++)
-        if ((*p)->src_name() == name && (*p)->src_port() == port)
-            tmp.push_back(lookup_block((*p)->dst_name()));
+  for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++)
+    if ((*p)->src().block() == block && (*p)->src().port() == port)
+      tmp.push_back((*p)->dst().block());
 
-    // Remove duplicates
-    sort(tmp.begin(), tmp.end());
-    unique_copy(tmp.begin(), tmp.end(), inserter);
-    return result;
+  // Remove duplicates
+  sort(tmp.begin(), tmp.end());
+  unique_copy(tmp.begin(), tmp.end(), inserter);
+  return result;
 }
 
-gr_block_vector_t
-gr_simple_flowgraph_detail::calc_downstream_blocks(const std::string &name)
+gr_basic_block_vector_t
+gr_simple_flowgraph_detail::calc_downstream_blocks(gr_basic_block_sptr block)
 {
-    gr_block_vector_t tmp, result;
-    std::insert_iterator<gr_block_vector_t> inserter(result, result.begin());
+  gr_basic_block_vector_t tmp, result;
+  std::insert_iterator<gr_basic_block_vector_t> inserter(result, result.begin());
 
-    for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++)
-        if ((*p)->src_name() == name)
-            tmp.push_back(lookup_block((*p)->dst_name()));
+  for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++)
+    if ((*p)->src().block() == block)
+      tmp.push_back((*p)->dst().block());
 
-    // Remove duplicates
-    sort(tmp.begin(), tmp.end());
-    unique_copy(tmp.begin(), tmp.end(), inserter);
-    return result;
+  // Remove duplicates
+  sort(tmp.begin(), tmp.end());
+  unique_copy(tmp.begin(), tmp.end(), inserter);
+  return result;
 }
 
 gr_edge_vector_t
-gr_simple_flowgraph_detail::calc_upstream_edges(const std::string &name)
+gr_simple_flowgraph_detail::calc_upstream_edges(gr_basic_block_sptr block)
 {
-    gr_edge_vector_t result;
+  gr_edge_vector_t result;
 
-    for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++)
-        if ((*p)->dst_name() == name)
-            result.push_back(*p);
+  for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++)
+    if ((*p)->dst().block() == block)
+      result.push_back(*p);
 
-    return result; // Assume no duplicates
+  return result; // Assume no duplicates
 }
 
-gr_block_vector_t
+gr_basic_block_vector_t
 gr_simple_flowgraph_detail::calc_used_blocks()
 {
-    std::vector<std::string> tmp, tmp_unique;
-    std::insert_iterator<std::vector<std::string> > inserter(tmp_unique, tmp_unique.begin());
-    gr_block_vector_t result;
+  gr_basic_block_vector_t tmp, result;
+  std::insert_iterator<gr_basic_block_vector_t> inserter(result, result.begin());
 
-    for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++) {
-        tmp.push_back((*p)->src_name());
-        tmp.push_back((*p)->dst_name());
-    }
-
-    sort(tmp.begin(), tmp.end());
-    unique_copy(tmp.begin(), tmp.end(), inserter);
-
-    for (std::vector<std::string>::iterator p = tmp_unique.begin();
-         p != tmp_unique.end(); p++)
-        result.push_back(lookup_block(*p));
-
-    if (GR_SIMPLE_FLOWGRAPH_DETAIL_DEBUG)
-        std::cout << "Flowgraph uses " << result.size()
-                  << " distinct blocks." << std::endl;
+  for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++) {
+    tmp.push_back((*p)->src().block());
+    tmp.push_back((*p)->dst().block());
+  }
 
-    return result;
+  sort(tmp.begin(), tmp.end());
+  unique_copy(tmp.begin(), tmp.end(), inserter);
+  return result;
 }
 
 std::vector<gr_block_vector_t>
 gr_simple_flowgraph_detail::partition()
 {
-    std::vector<gr_block_vector_t> result;
-    gr_block_vector_t blocks = calc_used_blocks();
-    gr_block_vector_t graph;
+  std::vector<gr_block_vector_t> result;
+  gr_basic_block_vector_t blocks = calc_used_blocks();
+  gr_basic_block_vector_t graph;
 
-    while (blocks.size() > 0) {
-        graph = calc_reachable_blocks(blocks[0], blocks);
-        assert(graph.size());
-        result.push_back(topological_sort(graph));
+  while (blocks.size() > 0) {
+    graph = calc_reachable_blocks(blocks[0], blocks);
+    assert(graph.size());
+    result.push_back(topological_sort(graph));
 
-        for (gr_block_viter_t p = graph.begin(); p != graph.end(); p++)
-            blocks.erase(find(blocks.begin(), blocks.end(), *p));
-    }
+    for (gr_basic_block_viter_t p = graph.begin(); p != graph.end(); p++)
+      blocks.erase(find(blocks.begin(), blocks.end(), *p));
+  }
 
-    return result;
+  return result;
 }
 
-gr_block_vector_t
-gr_simple_flowgraph_detail::calc_reachable_blocks(gr_block_sptr block, gr_block_vector_t &blocks)
+gr_basic_block_vector_t
+gr_simple_flowgraph_detail::calc_reachable_blocks(gr_basic_block_sptr block, gr_basic_block_vector_t &blocks)
 {
-    gr_block_vector_t result;
+  gr_basic_block_vector_t result;
 
-    // Mark all blocks as unvisited
-    for (gr_block_viter_t p = blocks.begin(); p != blocks.end(); p++)
-        (*p)->detail()->set_color(gr_block_detail::WHITE);
+  // Mark all blocks as unvisited
+  for (gr_basic_block_viter_t p = blocks.begin(); p != blocks.end(); p++)
+    boost::dynamic_pointer_cast<gr_block, gr_basic_block>(*p)->detail()->set_color(gr_block_detail::WHITE);
 
-    // Recursively mark all reachable blocks
-    reachable_dfs_visit(block, blocks);
+  // Recursively mark all reachable blocks
+  reachable_dfs_visit(block, blocks);
 
-    // Collect all the blocks that have been visited
-    for (gr_block_viter_t p = blocks.begin(); p != blocks.end(); p++)
-        if ((*p)->detail()->color() == gr_block_detail::BLACK)
-            result.push_back(*p);
+  // Collect all the blocks that have been visited
+  for (gr_basic_block_viter_t p = blocks.begin(); p != blocks.end(); p++)
+    if ((boost::dynamic_pointer_cast<gr_block, gr_basic_block>(*p))->detail()->color() == gr_block_detail::BLACK)
+      result.push_back(*p);
 
-    return result;
+  return result;
 }
 
 // Recursively mark all reachable blocks from given block and block list
 void 
-gr_simple_flowgraph_detail::reachable_dfs_visit(gr_block_sptr block, gr_block_vector_t &blocks)
+gr_simple_flowgraph_detail::reachable_dfs_visit(gr_basic_block_sptr block, gr_basic_block_vector_t &blocks)
 {
-    // Mark the current one as visited
-    block->detail()->set_color(gr_block_detail::BLACK);
+  // Mark the current one as visited
+  boost::dynamic_pointer_cast<gr_block, gr_basic_block>(block)->detail()->set_color(gr_block_detail::BLACK);
 
-    // Recurse into adjacent vertices
-    gr_block_vector_t adjacent = calc_adjacent_blocks(block, blocks);
+  // Recurse into adjacent vertices
+  gr_basic_block_vector_t adjacent = calc_adjacent_blocks(block, blocks);
 
-    for (gr_block_viter_t p = adjacent.begin(); p != adjacent.end(); p++)
-        if ((*p)->detail()->color() == gr_block_detail::WHITE)
-	        reachable_dfs_visit(*p, blocks);
+  for (gr_basic_block_viter_t p = adjacent.begin(); p != adjacent.end(); p++)
+    if (boost::dynamic_pointer_cast<gr_block, gr_basic_block>(*p)->detail()->color() == gr_block_detail::WHITE)
+      reachable_dfs_visit(*p, blocks);
 }
 
 // Return a list of block adjacent to a given block along any edge
-gr_block_vector_t 
-gr_simple_flowgraph_detail::calc_adjacent_blocks(gr_block_sptr block, gr_block_vector_t &blocks)
+gr_basic_block_vector_t 
+gr_simple_flowgraph_detail::calc_adjacent_blocks(gr_basic_block_sptr block, gr_basic_block_vector_t &blocks)
 {
-    gr_block_vector_t tmp, result;
-    std::insert_iterator<gr_block_vector_t> inserter(result, result.begin());
+  gr_basic_block_vector_t tmp, result;
+  std::insert_iterator<gr_basic_block_vector_t> inserter(result, result.begin());
     
-    // Find any blocks that are inputs or outputs
-    for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++) {
-        if (lookup_block((*p)->src_name()) == block)
-            tmp.push_back(lookup_block((*p)->dst_name()));
-        if (lookup_block((*p)->dst_name()) == block)
-            tmp.push_back(lookup_block((*p)->src_name()));
-    }    
-
-    // Remove duplicates
-    sort(tmp.begin(), tmp.end());
-    unique_copy(tmp.begin(), tmp.end(), inserter);
-    return result;
+  // Find any blocks that are inputs or outputs
+  for (gr_edge_viter_t p = d_edges.begin(); p != d_edges.end(); p++) {
+
+    if ((*p)->src().block() == block)
+      tmp.push_back((*p)->dst().block());
+    if ((*p)->dst().block() == block)
+      tmp.push_back((*p)->src().block());
+  }    
+
+  // Remove duplicates
+  sort(tmp.begin(), tmp.end());
+  unique_copy(tmp.begin(), tmp.end(), inserter);
+  return result;
 }
 
 gr_block_vector_t
-gr_simple_flowgraph_detail::topological_sort(gr_block_vector_t &blocks)
+gr_simple_flowgraph_detail::topological_sort(gr_basic_block_vector_t &blocks)
 {
-    gr_block_vector_t result, tmp;
-    tmp = sort_sources_first(blocks);
+  gr_basic_block_vector_t tmp;
+  gr_block_vector_t result;
+  tmp = sort_sources_first(blocks);
 
-    // Start 'em all white
-    for (gr_block_viter_t p = tmp.begin(); p != tmp.end(); p++)
-        (*p)->detail()->set_color(gr_block_detail::WHITE);
+  // Start 'em all white
+  for (gr_basic_block_viter_t p = tmp.begin(); p != tmp.end(); p++)
+    boost::dynamic_pointer_cast<gr_block, gr_basic_block>(*p)->detail()->set_color(gr_block_detail::WHITE);
 
-    for (gr_block_viter_t p = tmp.begin(); p != tmp.end(); p++) {
-        if ((*p)->detail()->color() == gr_block_detail::WHITE)
-            topological_dfs_visit(*p, result);
-    }    
+  for (gr_basic_block_viter_t p = tmp.begin(); p != tmp.end(); p++) {
+    if (boost::dynamic_pointer_cast<gr_block, gr_basic_block>(*p)->detail()->color() == gr_block_detail::WHITE)
+      topological_dfs_visit(*p, result);
+  }    
 
-    reverse(result.begin(), result.end());
+  reverse(result.begin(), result.end());
 
-    return result;
+  return result;
 }
 
 bool
-gr_simple_flowgraph_detail::source_p(gr_block_sptr block)
+gr_simple_flowgraph_detail::source_p(gr_basic_block_sptr block)
 {
-    return (calc_upstream_edges(lookup_name(block)).size() == 0);
+  return (calc_upstream_edges(block).size() == 0);
 }
 
-gr_block_vector_t
-gr_simple_flowgraph_detail::sort_sources_first(gr_block_vector_t &blocks)
+gr_basic_block_vector_t
+gr_simple_flowgraph_detail::sort_sources_first(gr_basic_block_vector_t &blocks)
 {
-    gr_block_vector_t sources, nonsources, result;
+  gr_basic_block_vector_t sources, nonsources, result;
 
-    for (gr_block_viter_t p = blocks.begin(); p != blocks.end(); p++) {
-        if (source_p(*p))
-            sources.push_back(*p);
-        else
-            nonsources.push_back(*p);
-    }
+  for (gr_basic_block_viter_t p = blocks.begin(); p != blocks.end(); p++) {
+    if (source_p(*p))
+      sources.push_back(*p);
+    else
+      nonsources.push_back(*p);
+  }
 
-    for (gr_block_viter_t p = sources.begin(); p != sources.end(); p++)
-        result.push_back(*p);
+  for (gr_basic_block_viter_t p = sources.begin(); p != sources.end(); p++)
+    result.push_back(*p);
 
-    for (gr_block_viter_t p = nonsources.begin(); p != nonsources.end(); p++)
-        result.push_back(*p);
+  for (gr_basic_block_viter_t p = nonsources.begin(); p != nonsources.end(); p++)
+    result.push_back(*p);
 
-    return result;
+  return result;
 }
 
 void
-gr_simple_flowgraph_detail::topological_dfs_visit(gr_block_sptr block, gr_block_vector_t &output)
+gr_simple_flowgraph_detail::topological_dfs_visit(gr_basic_block_sptr block, gr_block_vector_t &output)
 {
-    block->detail()->set_color(gr_block_detail::GREY);
+  boost::dynamic_pointer_cast<gr_block, gr_basic_block>(block)->detail()->set_color(gr_block_detail::GREY);
 
-    gr_block_vector_t blocks(calc_downstream_blocks(lookup_name(block)));
+  gr_basic_block_vector_t blocks(calc_downstream_blocks(block));
 
-    for (gr_block_viter_t p = blocks.begin(); p != blocks.end(); p++) {
-        switch ((*p)->detail()->color()) {
-            case gr_block_detail::WHITE:           
-                topological_dfs_visit(*p, output);
-                break;
+  for (gr_basic_block_viter_t p = blocks.begin(); p != blocks.end(); p++) {
+    switch (boost::dynamic_pointer_cast<gr_block, gr_basic_block>(*p)->detail()->color()) {
+    case gr_block_detail::WHITE:           
+      topological_dfs_visit(*p, output);
+      break;
 
-            case gr_block_detail::GREY:            
-                throw std::runtime_error("flow graph has loops!");
+    case gr_block_detail::GREY:            
+      throw std::runtime_error("flow graph has loops!");
 
-            case gr_block_detail::BLACK:
-                continue;
+    case gr_block_detail::BLACK:
+      continue;
 
-            default:
-                throw std::runtime_error("invalid color on block!");
-        }
+    default:
+      throw std::runtime_error("invalid color on block!");
     }
+  }
 
-    block->detail()->set_color(gr_block_detail::BLACK);
-    output.push_back(block);
+  gr_block_sptr result_block(boost::dynamic_pointer_cast<gr_block, gr_basic_block>(block));
+
+  result_block->detail()->set_color(gr_block_detail::BLACK);
+  output.push_back(result_block);
+}
+
+void
+gr_simple_flowgraph_detail::merge_connections(gr_simple_flowgraph_sptr sfg)
+{
+    // NOT IMPLEMENTED
 }
diff --git a/gnuradio-core/src/lib/runtime/gr_simple_flowgraph_detail.h b/gnuradio-core/src/lib/runtime/gr_simple_flowgraph_detail.h
index 2df1575ad..6e9058bba 100644
--- a/gnuradio-core/src/lib/runtime/gr_simple_flowgraph_detail.h
+++ b/gnuradio-core/src/lib/runtime/gr_simple_flowgraph_detail.h
@@ -1,6 +1,6 @@
 /* -*- c++ -*- */
 /*
- * Copyright 2006 Free Software Foundation, Inc.
+ * Copyright 2006,2007 Free Software Foundation, Inc.
  * 
  * This file is part of GNU Radio
  * 
@@ -23,48 +23,30 @@
 #ifndef INCLUDED_GR_SIMPLE_FLOWGRAPH_DETAIL_H
 #define INCLUDED_GR_SIMPLE_FLOWGRAPH_DETAIL_H
 
-#include <gr_block.h>
-#include <map>
+#include <gr_basic_block.h>
+#include <gr_simple_flowgraph.h>
+#include <iostream>
 
 #define GR_FIXED_BUFFER_SIZE (32*(1L<<10))
 
-typedef std::map<std::string, gr_block_sptr> gr_component_map_t;
-typedef std::map<std::string, gr_block_sptr>::iterator gr_component_miter_t;
-
-class gr_endpoint
-{
-private:
-    std::string d_name;
-    int d_port;
-
-public:
-    gr_endpoint(const std::string &name, int port) { d_name = name; d_port = port; }
-    const std::string &name() const { return d_name; }
-    int port() const { return d_port; }
-};    
-
 class gr_edge;
 typedef boost::shared_ptr<gr_edge> gr_edge_sptr;
-gr_edge_sptr gr_make_edge(const std::string &src_name, int src_port, 
-                          const std::string &dst_name, int dst_port);
+gr_edge_sptr gr_make_edge(const gr_endpoint &src, const gr_endpoint &dst);
 
 class gr_edge
 {
 private:
-    friend gr_edge_sptr gr_make_edge(const std::string &src_name, int src_port,
-                                     const std::string &dst_name, int dst_port);
-    gr_edge(const std::string &name, int src_port,
-            const std::string &name, int dst_port);
+  friend gr_edge_sptr gr_make_edge(const gr_endpoint &src, const gr_endpoint &dst);
+  gr_edge(const gr_endpoint &src, const gr_endpoint &dst) : d_src(src), d_dst(dst) { }
 
-    gr_endpoint d_src;
-    gr_endpoint d_dst;
+  gr_endpoint d_src;
+  gr_endpoint d_dst;
 
 public:
-    ~gr_edge();
-    const std::string src_name() const { return d_src.name(); }
-    const std::string dst_name() const { return d_dst.name(); }
-    int src_port() const { return d_src.port(); }
-    int dst_port() const { return d_dst.port(); }
+  ~gr_edge();
+
+  const gr_endpoint &src() const { return d_src; }
+  const gr_endpoint &dst() const { return d_dst; }
 };
 
 typedef std::vector<gr_edge_sptr> gr_edge_vector_t;
@@ -73,63 +55,68 @@ typedef std::vector<gr_edge_sptr>::iterator gr_edge_viter_t;
 class gr_simple_flowgraph_detail
 {
 private:
-    friend class gr_simple_flowgraph;
-    friend class gr_runtime_impl;
-    friend class topo_block_cmp;
+  friend class gr_simple_flowgraph;
+  friend class gr_runtime_impl;
+  friend class gr_hier_block2_detail;
+  friend class topo_block_cmp;
     
-    gr_simple_flowgraph_detail();
+  gr_simple_flowgraph_detail() : d_blocks(), d_edges() { }
 
-    gr_component_map_t d_components;
-    gr_edge_vector_t   d_edges;
-    static const unsigned int s_fixed_buffer_size = GR_FIXED_BUFFER_SIZE;
+  gr_basic_block_vector_t d_blocks;
+  gr_edge_vector_t  d_edges;
+  static const unsigned int s_fixed_buffer_size = GR_FIXED_BUFFER_SIZE;
     
-    void reset();
-    void define_component(const std::string &name, gr_block_sptr block);    
-    void connect(const std::string &src, int src_port, 
-                 const std::string &dst, int dst_port);
-    gr_block_sptr lookup_block(const std::string &name);
-    std::string lookup_name(const gr_block_sptr block);
-
-    void check_valid_port(gr_io_signature_sptr sig, int port);
-    void check_dst_not_used(const std::string &name, int port);
-    void check_type_match(gr_block_sptr src_block, int src_port,
-                          gr_block_sptr dst_block, int dst_port);
-    void validate();
-    gr_edge_vector_t calc_connections(const std::string &name, bool check_inputs); // false=use outputs
-    std::vector<int> calc_used_ports(const std::string &name, bool check_inputs); 
-    void check_contiguity(gr_block_sptr block, const std::vector<int> &used_ports, 
-                          bool check_inputs);
-    void setup_connections();
-    gr_buffer_sptr allocate_buffer(const std::string &name, int port);
-    gr_block_vector_t calc_downstream_blocks(const std::string &name, int port);
-    gr_block_vector_t calc_downstream_blocks(const std::string &name);
-    gr_edge_vector_t calc_upstream_edges(const std::string &name);
-    gr_block_vector_t calc_used_blocks();
-    std::vector<gr_block_vector_t> partition();
-    gr_block_vector_t calc_reachable_blocks(gr_block_sptr block, gr_block_vector_t &blocks);
-    gr_block_vector_t topological_sort(gr_block_vector_t &blocks);
-    void reachable_dfs_visit(gr_block_sptr block, gr_block_vector_t &blocks);
-    gr_block_vector_t calc_adjacent_blocks(gr_block_sptr block, gr_block_vector_t &blocks);
-    bool source_p(gr_block_sptr block);
-    gr_block_vector_t sort_sources_first(gr_block_vector_t &blocks);
-    void topological_dfs_visit(gr_block_sptr block, gr_block_vector_t &output);
+  void reset();
+  void connect(const gr_endpoint &src, const gr_endpoint &dst);
+  void disconnect(const gr_endpoint &src, const gr_endpoint &dst);
+  void check_valid_port(gr_io_signature_sptr sig, int port);
+  void check_dst_not_used(const gr_endpoint &dst);
+  void check_type_match(const gr_endpoint &src, const gr_endpoint &dst);
+  void validate();
+  gr_edge_vector_t calc_connections(gr_basic_block_sptr block, bool check_inputs); // false=use outputs
+  std::vector<int> calc_used_ports(gr_basic_block_sptr block, bool check_inputs); 
+  void check_contiguity(gr_basic_block_sptr block, const std::vector<int> &used_ports, bool check_inputs);
+  void setup_connections();
+  void merge_connections(gr_simple_flowgraph_sptr sfg);
+
+  gr_buffer_sptr allocate_buffer(gr_basic_block_sptr block, int port);
+  gr_basic_block_vector_t calc_downstream_blocks(gr_basic_block_sptr block, int port);
+  gr_basic_block_vector_t calc_downstream_blocks(gr_basic_block_sptr block);
+  gr_edge_vector_t calc_upstream_edges(gr_basic_block_sptr block);
+  gr_basic_block_vector_t calc_used_blocks();
+  std::vector<gr_block_vector_t> partition();
+  gr_basic_block_vector_t calc_reachable_blocks(gr_basic_block_sptr block, gr_basic_block_vector_t &blocks);
+  gr_block_vector_t topological_sort(gr_basic_block_vector_t &blocks);
+  void reachable_dfs_visit(gr_basic_block_sptr block, gr_basic_block_vector_t &blocks);
+  gr_basic_block_vector_t calc_adjacent_blocks(gr_basic_block_sptr block, gr_basic_block_vector_t &blocks);
+  bool source_p(gr_basic_block_sptr block);
+  gr_basic_block_vector_t sort_sources_first(gr_basic_block_vector_t &blocks);
+  void topological_dfs_visit(gr_basic_block_sptr block, gr_block_vector_t &output);
         
 public:
-    ~gr_simple_flowgraph_detail();
+  ~gr_simple_flowgraph_detail();
 };
 
 inline std::ostream&
-operator <<(std::ostream& os, const gr_block_sptr p)
+operator <<(std::ostream &os, const gr_endpoint endp)
 {
-    os << "<gr_block " << p->name() << " (" << p->unique_id() << ")>";
-    return os;
+  os << endp.block()->name() << ":" << endp.port();
+  return os;
 }
 
 inline std::ostream&
-operator <<(std::ostream &os, const gr_endpoint endp)
+operator <<(std::ostream &os, const gr_edge_sptr edge)
+{
+  os << edge->src() << "->" << edge->dst();
+  return os;
+}
+
+inline void
+enumerate_edges(gr_edge_vector_t &edges)
 {
-    os << endp.name() << ":" << endp.port();
-    return os;
+  std::cout << "Edge list has " << edges.size() << " elements" << std::endl;
+  for(gr_edge_viter_t p = edges.begin(); p != edges.end(); p++)
+    std::cout << *p << std::endl;
 }
 
 #endif /* INCLUDED_GR_SIMPLE_FLOWGRAPH_H */
diff --git a/gnuradio-core/src/lib/runtime/runtime.i b/gnuradio-core/src/lib/runtime/runtime.i
index cab338630..caa2166e0 100644
--- a/gnuradio-core/src/lib/runtime/runtime.i
+++ b/gnuradio-core/src/lib/runtime/runtime.i
@@ -28,7 +28,6 @@
 #include <gr_block_detail.h>
 #include <gr_hier_block2.h>
 #include <gr_runtime.h>
-#include <gr_simple_flowgraph.h>
 #include <gr_single_threaded_scheduler.h>
 #include <gr_message.h>
 #include <gr_msg_handler.h>
@@ -48,7 +47,6 @@
 %include <gr_block_detail.i>
 %include <gr_hier_block2.i>
 %include <gr_swig_block_magic.i>
-%include <gr_simple_flowgraph.i>
 %include <gr_single_threaded_scheduler.i>
 %include <gr_message.i>
 %include <gr_msg_handler.i>
diff --git a/gnuradio-core/src/python/gnuradio/blksimpl2/d8psk.py b/gnuradio-core/src/python/gnuradio/blksimpl2/d8psk.py
index b499b8fa3..2760eb77b 100644
--- a/gnuradio-core/src/python/gnuradio/blksimpl2/d8psk.py
+++ b/gnuradio-core/src/python/gnuradio/blksimpl2/d8psk.py
@@ -1,5 +1,5 @@
 #
-# Copyright 2005,2006 Free Software Foundation, Inc.
+# Copyright 2005,2006,2007 Free Software Foundation, Inc.
 # 
 # This file is part of GNU Radio
 # 
@@ -115,21 +115,9 @@ class d8psk_mod(gr.hier_block2):
 
 	self.rrc_filter = gr.interp_fir_filter_ccf(self._samples_per_symbol, self.rrc_taps)
 
-        # Define components from objects
-        self.define_component("bytes2chunks", self.bytes2chunks)
-        self.define_component("symbol_mapper", self.symbol_mapper)
-#        self.define_component("diffenc", self.diffenc)
-        self.define_component("chunks2symbols", self.chunks2symbols)
-        self.define_component("rrc_filter", self.rrc_filter)
-
 	# Connect components
-        self.connect("self", 0, "bytes2chunks", 0)
-        self.connect("bytes2chunks", 0, "symbol_mapper", 0)
-#        self.connect("symbol_mapper", 0, "diffenc", 0)
-#        self.connect("diffenc", 0, "chunks2symbols", 0)
-        self.connect("symbol_mapper", 0, "chunks2symbols", 0)
-        self.connect("chunks2symbols", 0, "rrc_filter", 0)
-        self.connect("rrc_filter", 0, "self", 0)
+	self.connect(self, self.bytes2chunks, self.symbol_mapper, self.chunks2symbols,
+		     self.rrc_filter, self)
 
         if verbose:
             self._print_verbage()
@@ -153,17 +141,10 @@ class d8psk_mod(gr.hier_block2):
 
     def _setup_logging(self):
         print "Modulation logging turned on."
-        self.define_component("bytes2chunks_dat", gr.file_sink(gr.sizeof_char, "tx_bytes2chunks.dat"))
-        self.define_component("symbol_mapper_dat", gr.file_sink(gr.sizeof_char, "tx_symbol_mapper.dat"))
-#        self.define_component("diffenc_dat", gr.file_sink(gr.sizeof_char, "tx_diffenc.dat"))
-        self.define_component("chunks2symbols_dat", gr.file_sink(gr.sizeof_gr_complex, "tx_chunks2symbols.dat"))
-        self.define_component("rrc_filter_dat", gr.file_sink(gr.sizeof_gr_complex, "tx_rrc_filter.dat"))
-
-        self.connect("bytes2chunks", 0, "bytes2chunks_dat", 0)
-        self.connect("symbol_mapper", 0, "symbol_mapper_dat", 0)
-#        self.connect("diffenc", 0, "diffenc_dat", 0)
-        self.connect("chunks2symbols", 0, "chunks2symbols_dat", 0)
-        self.connect("rrc_filter", 0, "rrc_filter_dat", 0)
+        self.connect(self.bytes2chunks, gr.file_sink(gr.sizeof_char, "tx_bytes2chunks.dat"))
+        self.connect(self.symbol_mapper, gr.file_sink(gr.sizeof_char, "tx_symbol_mapper.dat"))
+        self.connect(self.chunks2symbols, gr.file_sink(gr.sizeof_gr_complex, "tx_chunks2symbols.dat"))
+        self.connect(self.rrc_filter, gr.file_sink(gr.sizeof_gr_complex, "tx_rrc_filter.dat"))
 
     def add_options(parser):
         """
@@ -295,27 +276,9 @@ class d8psk_demod(gr.hier_block2):
         self.unpack = gr.unpack_k_bits_bb(self.bits_per_symbol())
 
  
-        # Define components
-        self.define_component("pre_scaler", self.pre_scaler)
-        self.define_component("agc", self.agc)
-        self.define_component("rrc_filter", self.rrc_filter)
-        self.define_component("receiver", self.receiver)
-        self.define_component("slicer", self.slicer)
-        #self.define_component("diffdec", self.diffdec)
-        self.define_component("symbol_mapper", self.symbol_mapper)
-        self.define_component("unpack", self.unpack)
-
         # Connect and Initialize base class
-        self.connect("self", 0, "pre_scaler", 0)
-        self.connect("pre_scaler", 0, "agc", 0)
-        self.connect("agc", 0, "rrc_filter", 0)
-        self.connect("rrc_filter", 0, "receiver", 0)
-        self.connect("receiver", 0, "slicer", 0)
-        #self.connect("slicer", 0, "diffdec", 0)
-        #self.connect("diffdec", 0, "symbol_mapper", 0)
-        self.connect("slicer", 0, "symbol_mapper", 0)
-        self.connect("symbol_mapper", 0, "unpack", 0)
-        self.connect("unpack", 0, "self", 0)
+	self.connect(self, self.pre_scaler, self.agc, self.rrc_filter, self.receiver,
+		     self.slicer, self.symbol_mapper, self.unpack, self)
 
         if verbose:
             self._print_verbage()
@@ -347,31 +310,13 @@ class d8psk_demod(gr.hier_block2):
 
     def _setup_logging(self):
         print "Demodulation logging turned on."
-        self.define_component("prescaler_dat",
-                              gr.file_sink(gr.sizeof_gr_complex, "rx_prescaler.dat"))
-        self.define_component("agc_dat",
-                              gr.file_sink(gr.sizeof_gr_complex, "rx_agc.dat"))
-        self.define_component("rrc_filter_dat",
-                              gr.file_sink(gr.sizeof_gr_complex, "rx_rrc_filter.dat"))
-        self.define_component("receiver_dat",
-                              gr.file_sink(gr.sizeof_gr_complex, "rx_receiver.dat"))
-        self.define_component("slicer_dat",
-                              gr.file_sink(gr.sizeof_char, "rx_slicer.dat"))
-#        self.define_component("diffdec_dat",
-#                              gr.file_sink(gr.sizeof_char, "rx_diffdec.dat"))
-        self.define_component("symbol_mapper_dat",
-                              gr.file_sink(gr.sizeof_char, "rx_symbol_mapper.dat"))
-        self.define_component("unpack_dat",
-                              gr.file_sink(gr.sizeof_char, "rx_unpack.dat"))
-
-        self.connect("pre_scaler", 0, "prescaler_dat", 0)
-        self.connect("agc", 0, "agc_dat", 0)
-        self.connect("rrc_filter", 0, "rrc_filter_dat", 0)
-        self.connect("receiver", 0, "receiver_dat", 0)
-        self.connect("slicer", 0, "slicer_dat", 0)
-#        self.connect("diffdec", 0, "diffdec_dat", 0)
-        self.connect("symbol_mapper", 0, "symbol_mapper_dat", 0)
-        self.connect("unpack", 0, "unpack_dat", 0)
+        self.connect(self.pre_scaler, gr.file_sink(gr.sizeof_gr_complex, "rx_prescaler.dat"))
+        self.connect(self.agc, gr.file_sink(gr.sizeof_gr_complex, "rx_agc.dat"))
+        self.connect(self.rrc_filter, gr.file_sink(gr.sizeof_gr_complex, "rx_rrc_filter.dat"))
+        self.connect(self.receiver, gr.file_sink(gr.sizeof_gr_complex, "rx_receiver.dat"))
+        self.connect(self.slicer, gr.file_sink(gr.sizeof_char, "rx_slicer.dat"))
+        self.connect(self.symbol_mapper, gr.file_sink(gr.sizeof_char, "rx_symbol_mapper.dat"))
+        self.connect(self.unpack, gr.file_sink(gr.sizeof_char, "rx_unpack.dat"))
 
     def add_options(parser):
         """
diff --git a/gnuradio-core/src/python/gnuradio/blksimpl2/dbpsk.py b/gnuradio-core/src/python/gnuradio/blksimpl2/dbpsk.py
index 36a2ea8af..380fa54f2 100644
--- a/gnuradio-core/src/python/gnuradio/blksimpl2/dbpsk.py
+++ b/gnuradio-core/src/python/gnuradio/blksimpl2/dbpsk.py
@@ -1,5 +1,5 @@
 #
-# Copyright 2005,2006 Free Software Foundation, Inc.
+# Copyright 2005,2006,2007 Free Software Foundation, Inc.
 # 
 # This file is part of GNU Radio
 # 
@@ -113,19 +113,9 @@ class dbpsk_mod(gr.hier_block2):
 	self.rrc_filter = gr.interp_fir_filter_ccf(self._samples_per_symbol,
                                                    self.rrc_taps)
 
-        self.define_component("bytes2chunks", self.bytes2chunks)
-        self.define_component("symbol_mapper", self.symbol_mapper)
-        self.define_component("diffenc", self.diffenc)
-        self.define_component("chunks2symbols", self.chunks2symbols)
-        self.define_component("rrc_filter", self.rrc_filter)
-
 	# Connect components
-        self.connect("self", 0, "bytes2chunks", 0)
-        self.connect("bytes2chunks", 0, "symbol_mapper", 0)
-        self.connect("symbol_mapper", 0, "diffenc", 0)
-        self.connect("diffenc", 0, "chunks2symbols", 0)
-        self.connect("chunks2symbols", 0, "rrc_filter", 0)
-        self.connect("rrc_filter", 0, "self", 0)
+	self.connect(self, self.bytes2chunks, self.symbol_mapper, self.diffenc, 
+		     self.chunks2symbols, self.rrc_filter, self)
 
         if verbose:
             self._print_verbage()
@@ -168,22 +158,11 @@ class dbpsk_mod(gr.hier_block2):
 
     def _setup_logging(self):
         print "Modulation logging turned on."
-        self.define_component("bytes2chunks_dat",
-                              gr.file_sink(gr.sizeof_char, "tx_bytes2chunks.dat"))
-        self.define_component("symbol_mapper_dat",
-                              gr.file_sink(gr.sizeof_char, "tx_symbol_mapper.dat"))
-        self.define_component("diffenc_dat",
-                              gr.file_sink(gr.sizeof_char, "tx_diffenc.dat"))
-        self.define_component("chunks2symbols_dat",
-                              gr.file_sink(gr.sizeof_gr_complex, "tx_chunks2symbols.dat"))
-        self.define_component("rrc_filter_dat",
-                              gr.file_sink(gr.sizeof_gr_complex, "tx_rrc_filter.dat"))
-
-        self.connect("bytes2chunks", 0, "bytes2chunks_dat", 0)
-        self.connect("symbol_mapper", 0, "symbol_mapper_dat", 0)
-        self.connect("diffenc", 0, "diffenc_dat", 0)
-        self.connect("chunks2symbols", 0, "chunks2symbols_dat", 0)
-        self.connect("rrc_filter", 0, "rrc_filter_dat", 0)
+        self.connect(self.bytes2chunks, gr.file_sink(gr.sizeof_char, "tx_bytes2chunks.dat"))
+        self.connect(self.symbol_mapper, gr.file_sink(gr.sizeof_char, "tx_symbol_mapper.dat"))
+        self.connect(self.diffenc, gr.file_sink(gr.sizeof_char, "tx_diffenc.dat"))
+        self.connect(self.chunks2symbols, gr.file_sink(gr.sizeof_gr_complex, "tx_chunks2symbols.dat"))
+        self.connect(self.rrc_filter, gr.file_sink(gr.sizeof_gr_complex, "tx_rrc_filter.dat"))
               
 
 # /////////////////////////////////////////////////////////////////////////////
@@ -295,27 +274,10 @@ class dbpsk_demod(gr.hier_block2):
         # unpack the k bit vector into a stream of bits
         self.unpack = gr.unpack_k_bits_bb(self.bits_per_symbol())
 
-        # Define components
-        self.define_component("pre_scaler", self.pre_scaler)
-        self.define_component("agc", self.agc)
-        self.define_component("rrc_filter", self.rrc_filter)
-        self.define_component("receiver", self.receiver)
-        self.define_component("slicer", self.slicer)
-        self.define_component("diffdec", self.diffdec)
-        self.define_component("symbol_mapper", self.symbol_mapper)
-        self.define_component("unpack", self.unpack)
-
         # Connect and Initialize base class
-        self.connect("self", 0, "pre_scaler", 0)
-        self.connect("pre_scaler", 0, "agc", 0)
-        self.connect("agc", 0, "rrc_filter", 0)
-        self.connect("rrc_filter", 0, "receiver", 0)
-        self.connect("receiver", 0, "diffdec", 0)
-        self.connect("diffdec", 0, "slicer", 0)
-        self.connect("slicer", 0, "symbol_mapper", 0)
-        self.connect("symbol_mapper", 0, "unpack", 0)
-        self.connect("unpack", 0, "self", 0)
-        
+	self.connect(self, self.pre_scaler, self.agc, self.rrc_filter, self.receiver,
+		     self.diffdec, self.slicer, self.symbol_mapper, self.unpack, self)
+
         if verbose:
             self._print_verbage()
 
@@ -344,32 +306,14 @@ class dbpsk_demod(gr.hier_block2):
 
     def _setup_logging(self):
         print "Demodulation logging turned on."
-        self.define_component("prescaler_dat",
-                              gr.file_sink(gr.sizeof_gr_complex, "rx_prescaler.dat"))
-        self.define_component("agc_dat",
-                              gr.file_sink(gr.sizeof_gr_complex, "rx_agc.dat"))
-        self.define_component("rrc_filter_dat",
-                              gr.file_sink(gr.sizeof_gr_complex, "rx_rrc_filter.dat"))
-        self.define_component("receiver_dat",
-                              gr.file_sink(gr.sizeof_gr_complex, "rx_receiver.dat"))
-        self.define_component("diffdec_dat",
-                              gr.file_sink(gr.sizeof_gr_complex, "rx_diffdec.dat"))
-        self.define_component("slicer_dat",
-                              gr.file_sink(gr.sizeof_char, "rx_slicer.dat"))
-        self.define_component("symbol_mapper_dat",
-                              gr.file_sink(gr.sizeof_char, "rx_symbol_mapper.dat"))
-        self.define_component("unpack_dat",
-                              gr.file_sink(gr.sizeof_char, "rx_unpack.dat"))
-
-        self.connect("pre_scaler", 0, "prescaler_dat", 0)
-        self.connect("agc", 0, "agc_dat", 0)
-        self.connect("rrc_filter", 0, "rrc_filter_dat", 0)
-        self.connect("receiver", 0, "receiver_dat", 0)
-        self.connect("diffdec", 0, "diffdec_dat", 0)
-        self.connect("slicer", 0, "slicer_dat", 0)
-        self.connect("symbol_mapper", 0, "symbol_mapper_dat", 0)
-        self.connect("unpack", 0, "unpack_dat", 0)
-
+        self.connect(self.pre_scaler, gr.file_sink(gr.sizeof_gr_complex, "rx_prescaler.dat"))
+        self.connect(self.agc, gr.file_sink(gr.sizeof_gr_complex, "rx_agc.dat"))
+        self.connect(self.rrc_filter, gr.file_sink(gr.sizeof_gr_complex, "rx_rrc_filter.dat"))
+        self.connect(self.receiver, gr.file_sink(gr.sizeof_gr_complex, "rx_receiver.dat"))
+        self.connect(self.diffdec, gr.file_sink(gr.sizeof_gr_complex, "rx_diffdec.dat"))
+        self.connect(self.slicer, gr.file_sink(gr.sizeof_char, "rx_slicer.dat"))
+        self.connect(self.symbol_mapper, gr.file_sink(gr.sizeof_char, "rx_symbol_mapper.dat"))
+        self.connect(self.unpack, gr.file_sink(gr.sizeof_char, "rx_unpack.dat"))
         
     def add_options(parser):
         """
diff --git a/gnuradio-core/src/python/gnuradio/blksimpl2/dqpsk.py b/gnuradio-core/src/python/gnuradio/blksimpl2/dqpsk.py
index 04623c93e..e9fc2092d 100644
--- a/gnuradio-core/src/python/gnuradio/blksimpl2/dqpsk.py
+++ b/gnuradio-core/src/python/gnuradio/blksimpl2/dqpsk.py
@@ -1,5 +1,5 @@
 #
-# Copyright 2005,2006 Free Software Foundation, Inc.
+# Copyright 2005,2006,2007 Free Software Foundation, Inc.
 # 
 # This file is part of GNU Radio
 # 
@@ -114,20 +114,9 @@ class dqpsk_mod(gr.hier_block2):
 
 	self.rrc_filter = gr.interp_fir_filter_ccf(self._samples_per_symbol, self.rrc_taps)
             
-        # Define components from objects
-        self.define_component("bytes2chunks", self.bytes2chunks)
-        self.define_component("symbol_mapper", self.symbol_mapper)
-        self.define_component("diffenc", self.diffenc)
-        self.define_component("chunks2symbols", self.chunks2symbols)
-        self.define_component("rrc_filter", self.rrc_filter)
-
 	# Connect components
-        self.connect("self", 0, "bytes2chunks", 0)
-        self.connect("bytes2chunks", 0, "symbol_mapper", 0)
-        self.connect("symbol_mapper", 0, "diffenc", 0)
-        self.connect("diffenc", 0, "chunks2symbols", 0)
-        self.connect("chunks2symbols", 0, "rrc_filter", 0)
-        self.connect("rrc_filter", 0, "self", 0)
+	self.connect(self, self.bytes2chunks, self.symbol_mapper, self.diffenc, 
+		     self.chunks2symbols, self.rrc_filter, self)
 
         if verbose:
             self._print_verbage()
@@ -150,17 +139,11 @@ class dqpsk_mod(gr.hier_block2):
 
     def _setup_logging(self):
         print "Modulation logging turned on."
-        self.define_component("bytes2chunks_dat", gr.file_sink(gr.sizeof_char, "tx_bytes2chunks.dat"))
-        self.define_component("symbol_mapper_dat", gr.file_sink(gr.sizeof_char, "tx_symbol_mapper.dat"))
-        self.define_component("diffenc_dat", gr.file_sink(gr.sizeof_char, "tx_diffenc.dat"))
-        self.define_component("chunks2symbols_dat", gr.file_sink(gr.sizeof_gr_complex, "tx_chunks2symbols.dat"))
-        self.define_component("rrc_filter_dat", gr.file_sink(gr.sizeof_gr_complex, "tx_rrc_filter.dat"))
-
-        self.connect("bytes2chunks", 0, "bytes2chunks_dat", 0)
-        self.connect("symbol_mapper", 0, "symbol_mapper_dat", 0)
-        self.connect("diffenc", 0, "diffenc_dat", 0)
-        self.connect("chunks2symbols", 0, "chunks2symbols_dat", 0)
-        self.connect("rrc_filter", 0, "rrc_filter_dat", 0)
+        self.connect(self.bytes2chunks, gr.file_sink(gr.sizeof_char, "tx_bytes2chunks.dat"))
+        self.connect(self.symbol_mapper, gr.file_sink(gr.sizeof_char, "tx_symbol_mapper.dat"))
+        self.connect(self.diffenc, gr.file_sink(gr.sizeof_char, "tx_diffenc.dat"))
+        self.connect(self.chunks2symbols, gr.file_sink(gr.sizeof_gr_complex, "tx_chunks2symbols.dat"))
+        self.connect(self.rrc_filter, gr.file_sink(gr.sizeof_gr_complex, "tx_rrc_filter.dat"))
 
     def add_options(parser):
         """
@@ -288,27 +271,10 @@ class dqpsk_demod(gr.hier_block2):
         
         # unpack the k bit vector into a stream of bits
         self.unpack = gr.unpack_k_bits_bb(self.bits_per_symbol())
- 
-        # Define components
-        self.define_component("pre_scaler", self.pre_scaler)
-        self.define_component("agc", self.agc)
-        self.define_component("rrc_filter", self.rrc_filter)
-        self.define_component("receiver", self.receiver)
-        self.define_component("diffdec", self.diffdec)
-        self.define_component("slicer", self.slicer)
-        self.define_component("symbol_mapper", self.symbol_mapper)
-        self.define_component("unpack", self.unpack)
 
         # Connect and Initialize base class
-        self.connect("self", 0, "pre_scaler", 0)
-        self.connect("pre_scaler", 0, "agc", 0)
-        self.connect("agc", 0, "rrc_filter", 0)
-        self.connect("rrc_filter", 0, "receiver", 0)
-        self.connect("receiver", 0, "diffdec", 0)
-        self.connect("diffdec", 0, "slicer", 0)
-        self.connect("slicer", 0, "symbol_mapper", 0)
-        self.connect("symbol_mapper", 0, "unpack", 0)
-        self.connect("unpack", 0, "self", 0)
+	self.connect(self, self.pre_scaler, self.agc, self.rrc_filter, self.receiver, self.diffdec,
+		     self.slicer, self.symbol_mapper, self.unpack, self)
 
         if verbose:
             self._print_verbage()
@@ -338,31 +304,14 @@ class dqpsk_demod(gr.hier_block2):
 
     def _setup_logging(self):
         print "Demodulation logging turned on."
-        self.define_component("prescaler_dat",
-                              gr.file_sink(gr.sizeof_gr_complex, "rx_prescaler.dat"))
-        self.define_component("agc_dat",
-                              gr.file_sink(gr.sizeof_gr_complex, "rx_agc.dat"))
-        self.define_component("rrc_filter_dat",
-                              gr.file_sink(gr.sizeof_gr_complex, "rx_rrc_filter.dat"))
-        self.define_component("receiver_dat",
-                              gr.file_sink(gr.sizeof_gr_complex, "rx_receiver.dat"))
-        self.define_component("diffdec_dat",
-                              gr.file_sink(gr.sizeof_gr_complex, "rx_diffdec.dat"))
-        self.define_component("slicer_dat",
-                              gr.file_sink(gr.sizeof_char, "rx_slicer.dat"))
-        self.define_component("symbol_mapper_dat",
-                              gr.file_sink(gr.sizeof_char, "rx_symbol_mapper.dat"))
-        self.define_component("unpack_dat",
-                              gr.file_sink(gr.sizeof_char, "rx_unpack.dat"))
-
-        self.connect("pre_scaler", 0, "prescaler_dat", 0)
-        self.connect("agc", 0, "agc_dat", 0)
-        self.connect("rrc_filter", 0, "rrc_filter_dat", 0)
-        self.connect("receiver", 0, "receiver_dat", 0)
-        self.connect("diffdec", 0, "diffdec_dat", 0)
-        self.connect("slicer", 0, "slicer_dat", 0)
-        self.connect("symbol_mapper", 0, "symbol_mapper_dat", 0)
-        self.connect("unpack", 0, "unpack_dat", 0)
+        self.connect(self.pre_scaler, gr.file_sink(gr.sizeof_gr_complex, "rx_prescaler.dat"))
+        self.connect(self.agc, gr.file_sink(gr.sizeof_gr_complex, "rx_agc.dat"))
+        self.connect(self.rrc_filter, gr.file_sink(gr.sizeof_gr_complex, "rx_rrc_filter.dat"))
+        self.connect(self.receiver, gr.file_sink(gr.sizeof_gr_complex, "rx_receiver.dat"))
+        self.connect(self.diffdec, gr.file_sink(gr.sizeof_gr_complex, "rx_diffdec.dat"))
+        self.connect(self.slicer, gr.file_sink(gr.sizeof_char, "rx_slicer.dat"))
+        self.connect(self.symbol_mapper, gr.file_sink(gr.sizeof_char, "rx_symbol_mapper.dat"))
+        self.connect(self.unpack, gr.file_sink(gr.sizeof_char, "rx_unpack.dat"))
 
     def add_options(parser):
         """
diff --git a/gnuradio-core/src/python/gnuradio/blksimpl2/gmsk.py b/gnuradio-core/src/python/gnuradio/blksimpl2/gmsk.py
index e852b3c11..bc601e679 100644
--- a/gnuradio-core/src/python/gnuradio/blksimpl2/gmsk.py
+++ b/gnuradio-core/src/python/gnuradio/blksimpl2/gmsk.py
@@ -2,7 +2,7 @@
 # GMSK modulation and demodulation.  
 #
 #
-# Copyright 2005,2006 Free Software Foundation, Inc.
+# Copyright 2005,2006,2007 Free Software Foundation, Inc.
 # 
 # This file is part of GNU Radio
 # 
@@ -103,16 +103,8 @@ class gmsk_mod(gr.hier_block2):
 	# FM modulation
 	self.fmmod = gr.frequency_modulator_fc(sensitivity)
 		
-        # Define components from objects
-        self.define_component("nrz", self.nrz)
-        self.define_component("gaussian_filter", self.gaussian_filter)
-        self.define_component("fmmod", self.fmmod)
-
 	# Connect components
-        self.connect("self", 0, "nrz", 0)
-        self.connect("nrz", 0, "gaussian_filter", 0)
-        self.connect("gaussian_filter", 0, "fmmod", 0)
-        self.connect("fmmod", 0, "self", 0)
+	self.connect(self, self.nrz, self.gaussian_filter, self.fmmod, self)
 
         if verbose:
             self._print_verbage()
@@ -135,13 +127,9 @@ class gmsk_mod(gr.hier_block2):
 
     def _setup_logging(self):
         print "Modulation logging turned on."
-        self.define_component("nrz_dat", gr.file_sink(gr.sizeof_float, "tx_nrz.dat"))
-        self.define_component("gaussian_filter_dat", gr.file_sink(gr.sizeof_float, "tx_gaussian_filter.dat"))
-        self.define_component("fmmod_dat", gr.file_sink(gr.sizeof_gr_complex, "tx_fmmod.dat"))
-
-        self.connect("nrz", 0, "nrz_dat", 0)
-        self.connect("gaussian_filter", 0, "gaussian_filter_dat", 0)
-        self.connect("fmmod", 0, "fmmod_dat", 0)
+        self.connect(self.nrz, gr.file_sink(gr.sizeof_float, "tx_nrz.dat"))
+        self.connect(self.gaussian_filter, gr.file_sink(gr.sizeof_float, "tx_gaussian_filter.dat"))
+        self.connect(self.fmmod, gr.file_sink(gr.sizeof_gr_complex, "tx_fmmod.dat"))
 
     def add_options(parser):
         """
@@ -232,16 +220,8 @@ class gmsk_demod(gr.hier_block2):
         # slice the floats at 0, outputting 1 bit (the LSB of the output byte) per sample
         self.slicer = gr.binary_slicer_fb()
 
-        # Define components from objects
-        self.define_component("fmdemod", self.fmdemod)
-        self.define_component("clock_recovery", self.clock_recovery)
-        self.define_component("slicer", self.slicer)
-
 	# Connect components
-        self.connect("self", 0, "fmdemod", 0)
-        self.connect("fmdemod", 0, "clock_recovery", 0)
-        self.connect("clock_recovery", 0, "slicer", 0)
-        self.connect("slicer", 0, "self", 0)
+	self.connect(self, self.fmdemod, self.clock_recovery, self.slicer, self)
 
         if verbose:
             self._print_verbage()
@@ -267,13 +247,9 @@ class gmsk_demod(gr.hier_block2):
 
     def _setup_logging(self):
         print "Demodulation logging turned on."
-        self.define_component("fmdemod_dat", gr.file_sink(gr.sizeof_float, "rx_fmdemod.dat"))
-        self.define_component("clock_recovery_dat", gr.file_sink(gr.sizeof_float, "rx_clock_recovery.dat"))
-        self.define_component("slicer_dat", gr.file_sink(gr.sizeof_char, "rx_slicer.dat"))
-
-        self.connect("fmdemod", 0, "fmdemod_dat", 0)
-        self.connect("clock_recovery", 0, "clock_recovery_dat", 0)
-        self.connect("slicer", 0, "slicer_dat", 0)
+        self.connect(self.fmdemod, gr.file_sink(gr.sizeof_float, "rx_fmdemod.dat"))
+        self.connect(self.clock_recovery, gr.file_sink(gr.sizeof_float, "rx_clock_recovery.dat"))
+        self.connect(self.slicer, gr.file_sink(gr.sizeof_char, "rx_slicer.dat"))
 
     def add_options(parser):
         """
diff --git a/gnuradio-core/src/python/gnuradio/blksimpl2/pkt.py b/gnuradio-core/src/python/gnuradio/blksimpl2/pkt.py
index 1e1dae17a..c94c27338 100644
--- a/gnuradio-core/src/python/gnuradio/blksimpl2/pkt.py
+++ b/gnuradio-core/src/python/gnuradio/blksimpl2/pkt.py
@@ -1,5 +1,5 @@
 #
-# Copyright 2005,2006 Free Software Foundation, Inc.
+# Copyright 2005,2006,2007 Free Software Foundation, Inc.
 # 
 # This file is part of GNU Radio
 # 
@@ -67,11 +67,7 @@ class mod_pkts(gr.hier_block2):
 
         # accepts messages from the outside world
         self._pkt_input = gr.message_source(gr.sizeof_char, msgq_limit)
-        self.define_component("packet_source", self._pkt_input)
-        self.define_component("modulator", self._modulator)
-
-        self.connect("packet_source", 0, "modulator", 0)
-        self.connect("modulator", 0, "self", 0)
+	self.connect(self._pkt_input, self._modulator, self)
 
     def send_pkt(self, payload='', eof=False):
         """
@@ -136,13 +132,9 @@ class demod_pkts(gr.hier_block2):
 
         self._rcvd_pktq = gr.msg_queue()          # holds packets from the PHY
 
-        self.define_component("demodulator", self._demodulator)
-        self.define_component("correlator", gr.correlate_access_code_bb(access_code, threshold))
-        self.define_component("framer_sink", gr.framer_sink_1(self._rcvd_pktq))
-
-        self.connect("self", 0, "demodulator",0)
-        self.connect("demodulator", 0, "correlator", 0)
-        self.connect("correlator", 0, "framer_sink", 0)
+        self._correlator = gr.correlate_access_code_bb(access_code, threshold)
+        self._framer_sink = gr.framer_sink_1(self._rcvd_pktq)
+	self.connect(self, self._demodulator, self._correlator, self._framer_sink)
 
         self._watcher = _queue_watcher_thread(self._rcvd_pktq, callback)
 
diff --git a/gnuradio-core/src/python/gnuradio/gr/hier_block2.py b/gnuradio-core/src/python/gnuradio/gr/hier_block2.py
index 5877401b5..4abe9d14f 100644
--- a/gnuradio-core/src/python/gnuradio/gr/hier_block2.py
+++ b/gnuradio-core/src/python/gnuradio/gr/hier_block2.py
@@ -21,7 +21,7 @@
 
 from gnuradio_swig_python import hier_block2_swig, gr_make_runtime, \
     runtime_run_unlocked, runtime_start_unlocked, runtime_stop_unlocked, \
-    runtime_wait_unlocked 
+    runtime_wait_unlocked, runtime_restart_unlocked, io_signature
 
 #
 # This hack forces a 'has-a' relationship to look like an 'is-a' one.
@@ -38,9 +38,55 @@ class hier_block2(object):
     def __getattr__(self, name):
 	return getattr(self._hb, name)
 
-    def define_component(self, name, comp):
-	return self._hb.define_component(name, comp.basic_block())
+    def connect(self, *points):
+        '''connect requires two or more arguments that can be coerced to endpoints.
+        If more than two arguments are provided, they are connected together successively.
+        '''
+        if len (points) < 2:
+            raise ValueError, ("connect requires at least two endpoints; %d provided." % (len (points),))
+        for i in range (1, len (points)):
+            self._connect(points[i-1], points[i])
 
+    def _connect(self, src, dst):
+        (src_block, src_port) = self._coerce_endpoint(src)
+        (dst_block, dst_port) = self._coerce_endpoint(dst)
+        self._hb.connect(src_block.basic_block(), src_port,
+                         dst_block.basic_block(), dst_port)
+
+    def _coerce_endpoint(self, endp):
+        if hasattr(endp, 'basic_block'):
+            return (endp, 0)
+        else:
+            if hasattr(endp, "__getitem__") and len(endp) == 2:
+                return endp # Assume user put (block, port)
+            else:
+                raise ValueError("unable to coerce endpoint")
+
+    def disconnect(self, *points):
+        '''connect requires two or more arguments that can be coerced to endpoints.
+        If more than two arguments are provided, they are disconnected successively.
+        '''
+        if len (points) < 2:
+            raise ValueError, ("disconnect requires at least two endpoints; %d provided." % (len (points),))
+        for i in range (1, len (points)):
+            self._disconnect(points[i-1], points[i])
+
+    def _disconnect(self, src, dst):
+        (src_block, src_port) = self._coerce_endpoint(src)
+        (dst_block, dst_port) = self._coerce_endpoint(dst)
+        self._hb.disconnect(src_block.basic_block(), src_port,
+                            dst_block.basic_block(), dst_port)
+
+# Convenience class to create a no input, no output block for runtime top block
+class top_block(hier_block2):
+    def __init__(self, name):
+        hier_block2.__init__(self, name, io_signature(0,0,0), io_signature(0,0,0))
+
+# This allows the 'run_locked' methods, which are defined in gr_runtime.i,
+# to release the Python global interpreter lock before calling the actual
+# method in gr.runtime
+#
+# This probably should be elsewhere but it works here
 class runtime(object):
     def __init__(self, top_block):
         if (isinstance(top_block, hier_block2)):
@@ -59,3 +105,6 @@ class runtime(object):
 
     def wait(self):
         runtime_wait_unlocked(self._r)
+
+    def restart(self):
+        runtime_restart_unlocked(self._r)
diff --git a/gnuradio-core/src/python/gnuradio/gr/qa_hier_block2.py b/gnuradio-core/src/python/gnuradio/gr/qa_hier_block2.py
index 9253b892a..98691cfb5 100755
--- a/gnuradio-core/src/python/gnuradio/gr/qa_hier_block2.py
+++ b/gnuradio-core/src/python/gnuradio/gr/qa_hier_block2.py
@@ -6,10 +6,10 @@ class test_hier_block2(gr_unittest.TestCase):
 
     def setUp(self):
 	pass
-	
+
     def tearDown(self):
     	pass
-	
+
     def test_001_make(self):
 	hblock = gr.hier_block2("test_block", 
 				gr.io_signature(1,1,gr.sizeof_int), 
@@ -20,219 +20,155 @@ class test_hier_block2(gr_unittest.TestCase):
 	self.assertEqual(1, hblock.output_signature().max_streams())
 	self.assertEqual(gr.sizeof_int, hblock.output_signature().sizeof_stream_item(0))
 
-    def test_002_define_component(self):
+    def test_001_connect_internal(self):
 	hblock = gr.hier_block2("test_block", 
 				gr.io_signature(1,1,gr.sizeof_int), 
 				gr.io_signature(1,1,gr.sizeof_int))
-	hblock.define_component("src", gr.null_source(gr.sizeof_int))
-	hblock.define_component("dst", gr.null_sink(gr.sizeof_int))
+	nop1 = gr.nop(gr.sizeof_int)
+	nop2 = gr.nop(gr.sizeof_int)
+	hblock.connect(nop1, nop2)
 
-    def test_003_define_component_reserved_input(self):
+    def test_002_connect_input(self):
 	hblock = gr.hier_block2("test_block", 
 				gr.io_signature(1,1,gr.sizeof_int), 
 				gr.io_signature(1,1,gr.sizeof_int))
-	self.assertRaises(ValueError, 
-	    lambda: hblock.define_component("self", gr.nop(gr.sizeof_int)))
+	nop1 = gr.nop(gr.sizeof_int)
+	hblock.connect(hblock, nop1)
 
-    def test_004_define_component_name_in_use(self):
+    def test_002a_connect_input_in_use(self):
 	hblock = gr.hier_block2("test_block", 
 				gr.io_signature(1,1,gr.sizeof_int), 
 				gr.io_signature(1,1,gr.sizeof_int))
-	hblock.define_component("src", gr.null_source(gr.sizeof_int))
-	self.assertRaises(ValueError, 
-	    lambda: hblock.define_component("src", gr.null_sink(gr.sizeof_int)))
+	nop1 = gr.nop(gr.sizeof_int)
+	nop2 = gr.nop(gr.sizeof_int)
+	hblock.connect(hblock, nop1)
+	self.assertRaises(ValueError,
+	    lambda: hblock.connect(hblock, nop2))
 
-    def test_006_connect_internal(self):
+    def test_003_connect_output(self):
 	hblock = gr.hier_block2("test_block", 
 				gr.io_signature(1,1,gr.sizeof_int), 
 				gr.io_signature(1,1,gr.sizeof_int))
-	hblock.define_component("nop1", gr.nop(gr.sizeof_int))
-	hblock.define_component("nop2", gr.nop(gr.sizeof_int))
-	hblock.connect("nop1", 0, "nop2", 0)
+	nop1 = gr.nop(gr.sizeof_int)
+	hblock.connect(nop1, hblock)
 
-    def test_007_connect_input(self):
+    def test_003a_connect_output_in_use(self):
 	hblock = gr.hier_block2("test_block", 
 				gr.io_signature(1,1,gr.sizeof_int), 
 				gr.io_signature(1,1,gr.sizeof_int))
-	hblock.define_component("nop1", gr.nop(gr.sizeof_int))
-	hblock.connect("self", 0, "nop1", 0)
+	nop1 = gr.nop(gr.sizeof_int)
+	nop2 = gr.nop(gr.sizeof_int)
+	hblock.connect(nop1, hblock)
+	self.assertRaises(ValueError,
+	    lambda: hblock.connect(nop2, hblock))
 
-    def test_008_connect_output(self):
+    def test_004_connect_invalid_src_port_neg(self):
 	hblock = gr.hier_block2("test_block", 
 				gr.io_signature(1,1,gr.sizeof_int), 
 				gr.io_signature(1,1,gr.sizeof_int))
-	hblock.define_component("nop1", gr.nop(gr.sizeof_int))
-	hblock.connect("nop1", 0, "self", 0)
+	nop1 = gr.nop(gr.sizeof_int)
+	self.assertRaises(ValueError, 
+	    lambda: hblock.connect((hblock, -1), nop1))
 
-    def test_009_connect_unknown_src(self):
+    def test_005_connect_invalid_src_port_exceeds(self):
 	hblock = gr.hier_block2("test_block", 
 				gr.io_signature(1,1,gr.sizeof_int), 
 				gr.io_signature(1,1,gr.sizeof_int))
 	nop1 = gr.nop(gr.sizeof_int)
-	hblock.define_component("nop1", nop1)
 	self.assertRaises(ValueError, 
-	    lambda: hblock.connect("nop2", 0, "self", 0))
-    
-    def test_010_connect_unknown_dst(self):
+	    lambda: hblock.connect((hblock, 1), nop1))
+
+    def test_006_connect_invalid_dst_port_neg(self):
 	hblock = gr.hier_block2("test_block", 
 				gr.io_signature(1,1,gr.sizeof_int), 
 				gr.io_signature(1,1,gr.sizeof_int))
-	hblock.define_component("nop1", gr.nop(gr.sizeof_int))
+	nop1 = gr.nop(gr.sizeof_int)
+	nop2 = gr.nop(gr.sizeof_int)
 	self.assertRaises(ValueError, 
-	    lambda: hblock.connect("self", 0, "nop2", 0))
+	    lambda: hblock.connect(nop1, (nop2, -1)))
 
-    def test_011_connect_invalid_src_port_neg(self):
+    def test_007_connect_invalid_dst_port_exceeds(self):
 	hblock = gr.hier_block2("test_block", 
 				gr.io_signature(1,1,gr.sizeof_int), 
 				gr.io_signature(1,1,gr.sizeof_int))
-	hblock.define_component("nop1", gr.nop(gr.sizeof_int))
+	nop1 = gr.null_sink(gr.sizeof_int)
+	nop2 = gr.null_sink(gr.sizeof_int)
 	self.assertRaises(ValueError, 
-	    lambda: hblock.connect("self", -1, "nop1", 0))
+	    lambda: hblock.connect(nop1, (nop2, 1)))
 
-    def test_012_connect_invalid_src_port_exceeds(self):
+    def test_008_connect_dst_port_in_use(self):
 	hblock = gr.hier_block2("test_block", 
 				gr.io_signature(1,1,gr.sizeof_int), 
 				gr.io_signature(1,1,gr.sizeof_int))
-	hblock.define_component("nop1", gr.nop(gr.sizeof_int))
+	nop1 = gr.nop(gr.sizeof_int)
+	nop2 = gr.nop(gr.sizeof_int)
+	hblock.connect(nop1, nop2);
 	self.assertRaises(ValueError, 
-	    lambda: hblock.connect("self", 1, "nop1", 0))
-    
-    def test_013_connect_invalid_dst_port_neg(self):
-	hblock = gr.hier_block2("test_block", 
-				gr.io_signature(1,1,gr.sizeof_int), 
-				gr.io_signature(1,1,gr.sizeof_int))
-	hblock.define_component("nop1", gr.nop(gr.sizeof_int))
+	    lambda: hblock.connect(nop1, nop2))
+
+    def test_009_connect_one_src_two_dst(self):
+	hblock = gr.top_block("test_block")
+	src = gr.null_source(gr.sizeof_int)
+	dst1 = gr.null_sink(gr.sizeof_int)
+	dst2 = gr.null_sink(gr.sizeof_int)
+	hblock.connect(src, dst1)
+	hblock.connect(src, dst2)
+
+    def test_010_connect_type_mismatch(self):
+	hblock = gr.top_block("test_block")
+	nop1 = gr.nop(gr.sizeof_char)
+	nop2 = gr.nop(gr.sizeof_int)
 	self.assertRaises(ValueError, 
-	    lambda: hblock.connect("self", -1, "nop1", 0))
+	    lambda: hblock.connect(nop1, nop2))
 
-    def test_014_connect_invalid_dst_port_exceeds(self):
-	hblock = gr.hier_block2("test_block", 
-				gr.io_signature(1,1,gr.sizeof_int), 
-				gr.io_signature(1,1,gr.sizeof_int))
-	hblock.define_component("nop1", gr.nop(gr.sizeof_int))
-	self.assertRaises(ValueError, 
-	    lambda: hblock.connect("self", 1, "nop1", 0))
+    def test_011_check_topology(self):
+	hblock = gr.top_block("test_block")
+	hblock.check_topology(0, 0)
 
-    def test_015_connect_dst_port_in_use(self):
-	hblock = gr.hier_block2("test_block", 
-				gr.io_signature(1,1,gr.sizeof_int), 
-				gr.io_signature(1,1,gr.sizeof_int))
+    def test_012_disconnect(self):
+	hblock = gr.top_block("test_block") 
 	nop1 = gr.nop(gr.sizeof_int)
-	hblock.define_component("nop1", nop1)
-	hblock.connect("nop1", 0, "self", 0);
-	self.assertRaises(ValueError, 
-	    lambda: hblock.connect("nop1", 0, "self", 0))
-    
-    def test_016_connect_one_src_two_dst(self):
-	hblock = gr.hier_block2("test_block", 
-				gr.io_signature(1,1,gr.sizeof_int), 
-				gr.io_signature(1,1,gr.sizeof_int))
-	hblock.define_component("src", gr.null_source(gr.sizeof_int))
-	hblock.define_component("dst1", gr.null_sink(gr.sizeof_int))
-	hblock.define_component("dst2", gr.null_sink(gr.sizeof_int))
-	hblock.connect("src", 0, "dst1", 0)
-	hblock.connect("src", 0, "dst2", 0)
+	nop2 = gr.nop(gr.sizeof_int)
+	hblock.connect(nop1, nop2)
+        hblock.disconnect(nop1, nop2)
 
-    def test_017_connect_type_mismatch(self):
+    def test_013_disconnect_not_connected(self):
 	hblock = gr.hier_block2("test_block", 
 				gr.io_signature(1,1,gr.sizeof_int), 
 				gr.io_signature(1,1,gr.sizeof_int))
-	hblock.define_component("nop1", gr.nop(gr.sizeof_char))
+	nop1 = gr.nop(gr.sizeof_int)
+	nop2 = gr.nop(gr.sizeof_int)
+	nop3 = gr.nop(gr.sizeof_int)
+	hblock.connect(nop1, nop2)
 	self.assertRaises(ValueError, 
-	    lambda: hblock.connect("nop1", 0, "self", 0))
-
-    def test_018_check_topology(self):
-	hblock = gr.hier_block2("test_block", 
-				gr.io_signature(0,0,gr.sizeof_int), 
-				gr.io_signature(0,0,gr.sizeof_int))
-	hblock.check_topology(0, 0);
-    """
-    def test_019_validate(self):
-	hblock = gr.hier_block2("test_block", 
-				gr.io_signature(0,0,gr.sizeof_int), 
-				gr.io_signature(0,0,gr.sizeof_int))
-	runtime = gr.runtime(hblock)
-	runtime.validate()
+	    lambda: hblock.disconnect(nop1, nop3))
+
+    def test_014_run(self):
+        expected = (1.0, 2.0, 3.0, 4.0)
+        hblock = gr.top_block("test_block")
+        src = gr.vector_source_f(expected, False)
+        sink1 = gr.vector_sink_f()
+        sink2 = gr.vector_sink_f()
+        hblock.connect(src, sink1)
+        hblock.connect(src, sink2)
+        runtime = gr.runtime(hblock)
+        runtime.run()
+        actual1 = sink1.data()
+        actual2 = sink2.data()
+        self.assertEquals(expected, actual1)
+        self.assertEquals(expected, actual2)
+
+    def test_015_connect_disconnect(self):
+        expected = (1.0, 2.0, 3.0, 4.0)
+        hblock = gr.top_block("test_block")
+        src = gr.vector_source_f(expected, False)
+        sink1 = gr.vector_sink_f()
+        sink2 = gr.vector_sink_f()
+        hblock.connect(src, sink1)
+        hblock.connect(src, sink2)
+        hblock.disconnect(src, sink2)
+        runtime = gr.runtime(hblock)
+        runtime.run()
     
-    def test_020_validate_1(self):
-	hblock = gr.hier_block2("test_block", 
-				gr.io_signature(0,0,gr.sizeof_int), 
-				gr.io_signature(0,0,gr.sizeof_int))
-	hblock.define_component("src", gr.null_source(gr.sizeof_int))
-	hblock.define_component("dst1", gr.null_sink(gr.sizeof_int))
-	hblock.define_component("dst2", gr.null_sink(gr.sizeof_int))
-	hblock.connect("src", 0, "dst1", 0)
-	hblock.connect("src", 0, "dst2", 0)			
-	runtime = gr.runtime(hblock)
-	runtime.validate()
-
-    def test_021_validate_2(self):
-	hblock = gr.hier_block2("test_block", 
-				gr.io_signature(0,0,gr.sizeof_int), 
-				gr.io_signature(0,0,gr.sizeof_int))
-	hblock.define_component("src1", gr.null_source(gr.sizeof_int))
-	hblock.define_component("nop1", gr.nop(gr.sizeof_int))
-	hblock.define_component("dst1", gr.null_sink(gr.sizeof_int))
-	hblock.define_component("dst2", gr.null_sink(gr.sizeof_int))
-	hblock.connect("src1", 0, "nop1", 0)
-	hblock.connect("src1", 0, "nop1", 1)
-	hblock.connect("nop1", 0, "dst1", 0)
-	hblock.connect("nop1", 1, "dst2", 0)
-	runtime = gr.runtime(hblock)
-	runtime.validate()
-        
-    def test_022_validate_3(self):
-	hblock = gr.hier_block2("test_block", 
-				gr.io_signature(0,0,gr.sizeof_int), 
-				gr.io_signature(0,0,gr.sizeof_int))
-	hblock.define_component("src1", gr.null_source(gr.sizeof_int))
-	hblock.define_component("nop1", gr.nop(gr.sizeof_int))
-	hblock.define_component("dst1", gr.null_sink(gr.sizeof_int))
-	hblock.define_component("dst2", gr.null_sink(gr.sizeof_int))
-	hblock.connect("src1", 0, "nop1", 0)
-	hblock.connect("src1", 0, "nop1", 2)
-	hblock.connect("nop1", 0, "dst1", 0)
-	hblock.connect("nop1", 1, "dst2", 0)
-	runtime = gr.runtime(hblock)
-	self.assertRaises(RuntimeError,
-	    lambda: runtime.validate())
-        
-    def test_023_validate_4(self):
-	hblock = gr.hier_block2("test_block", 
-				gr.io_signature(0,0,gr.sizeof_int), 
-				gr.io_signature(0,0,gr.sizeof_int))
-	hblock.define_component("src1", gr.null_source(gr.sizeof_int))
-	hblock.define_component("nop1", gr.nop(gr.sizeof_int))
-	hblock.define_component("dst1", gr.null_sink(gr.sizeof_int))
-	hblock.define_component("dst2", gr.null_sink(gr.sizeof_int))
-	hblock.connect("src1", 0, "nop1", 0)
-	hblock.connect("src1", 0, "nop1", 1)
-	hblock.connect("nop1", 0, "dst1", 0)
-	hblock.connect("nop1", 2, "dst2", 0)
-	runtime = gr.runtime(hblock)
-	self.assertRaises(RuntimeError,
-	    lambda: runtime.validate())
-        
-    def test_024_validate_5(self):
-	hblock = gr.hier_block2("test_block", 
-				gr.io_signature(0,0,gr.sizeof_int), 
-				gr.io_signature(0,0,gr.sizeof_int))
-	hblock.define_component("src1", gr.null_source(gr.sizeof_int))
-	hblock.define_component("nop1", gr.nop(gr.sizeof_int))
-	hblock.define_component("dst1", gr.null_sink(gr.sizeof_int))
-	hblock.define_component("dst2", gr.null_sink(gr.sizeof_int))
-	hblock.connect("src1", 0, "nop1", 0)
-	hblock.connect("src1", 0, "nop1", 1)
-	hblock.connect("nop1", 0, "dst1", 0)
-	hblock.connect("nop1", 1, "dst2", 0)
-	runtime = gr.runtime(hblock)
-	runtime.validate()
-	# Pending implementation of disconnect
-	# hblock.disconnect("src1", 0, "nop1", 1)
-	# runtime.validate()	
-	# self.assertRaises(ValueError,
-	#     lambda: hblock.disconnect("src1", 0, "nop1", 1))
-	"""
-	        
 if __name__ == "__main__":
     gr_unittest.main()
diff --git a/gnuradio-core/src/python/gnuradio/gr/qa_simple_flowgraph.py b/gnuradio-core/src/python/gnuradio/gr/qa_simple_flowgraph.py
deleted file mode 100755
index 939f5855f..000000000
--- a/gnuradio-core/src/python/gnuradio/gr/qa_simple_flowgraph.py
+++ /dev/null
@@ -1,142 +0,0 @@
-#!/usr/bin/env python
-
-from gnuradio import gr, gr_unittest
-
-class test_simple_flowgraph(gr_unittest.TestCase):
-
-    def setUp(self):
-	pass
-	
-    def tearDown(self):
-	pass
-			
-    def test_001_define_component(self):
-	sfg = gr.simple_flowgraph()
-	sfg.define_component("src", gr.null_source(gr.sizeof_int))
-	sfg.define_component("dst", gr.null_sink(gr.sizeof_int))
-
-    def test_002_define_component_name_in_use(self):
-	sfg = gr.simple_flowgraph()
-	sfg.define_component("src", gr.null_source(gr.sizeof_int))
-	self.assertRaises(ValueError, 
-	    lambda: sfg.define_component("src", gr.null_sink(gr.sizeof_int)))
-    
-    def test_003_connect(self):
-	sfg = gr.simple_flowgraph()
-	sfg.define_component("src", gr.null_source(gr.sizeof_int))
-	sfg.define_component("dst", gr.null_sink(gr.sizeof_int))
-	sfg.connect("src", 0, "dst", 0)
-
-    def test_004connect_unknown_src(self):
-	sfg = gr.simple_flowgraph()
-	sfg.define_component("dst", gr.null_sink(gr.sizeof_int))
-	self.assertRaises(ValueError, 
-	    lambda: sfg.connect("src", 0, "dst", 0))
-    
-    def test_005_connect_unknown_dst(self):
-	sfg = gr.simple_flowgraph()
-	sfg.define_component("src", gr.null_source(gr.sizeof_int))
-	self.assertRaises(ValueError, 
-	    lambda: sfg.connect("src", 0, "dst", 0))
-
-    def test_006_connect_invalid_src_port_neg(self):
-	sfg = gr.simple_flowgraph()
-	sfg.define_component("src", gr.null_source(gr.sizeof_int))
-	sfg.define_component("dst", gr.null_sink(gr.sizeof_int))
-	self.assertRaises(ValueError, 
-	    lambda: sfg.connect("src", -1, "dst", 0))
-
-    def test_007_connect_invalid_src_port_exceeds(self):
-	sfg = gr.simple_flowgraph()
-	sfg.define_component("src", gr.null_source(gr.sizeof_int))
-	sfg.define_component("dst", gr.null_sink(gr.sizeof_int))
-	self.assertRaises(ValueError, 
-	    lambda: sfg.connect("src", 1, "dst", 0))
-
-    def test_008_connect_invalid_dst_port_neg(self):
-	sfg = gr.simple_flowgraph()
-	sfg.define_component("src", gr.null_source(gr.sizeof_int))
-	sfg.define_component("dst", gr.null_sink(gr.sizeof_int))
-	self.assertRaises(ValueError, 
-	    lambda: sfg.connect("src", 0, "dst", -1))
-
-    def test_009_connect_invalid_dst_port_exceeds(self):
-	sfg = gr.simple_flowgraph()
-	sfg.define_component("src", gr.null_source(gr.sizeof_int))
-	sfg.define_component("dst", gr.null_sink(gr.sizeof_int))
-	self.assertRaises(ValueError, 
-	    lambda: sfg.connect("src", 0, "dst", 1))
-
-    def test_010_connect_invalid_dst_port_in_use(self):
-	sfg = gr.simple_flowgraph()
-	sfg.define_component("src1", gr.null_source(gr.sizeof_int))
-	sfg.define_component("src2", gr.null_source(gr.sizeof_int))
-	sfg.define_component("dst", gr.null_sink(gr.sizeof_int))
-	sfg.connect("src1", 0, "dst", 0)
-	self.assertRaises(ValueError, 
-	    lambda: sfg.connect("src2", 0, "dst", 0))
-    
-    def test_011_connect_one_src_two_dst(self):
-	sfg = gr.simple_flowgraph()
-	sfg.define_component("src", gr.null_source(gr.sizeof_int))
-	sfg.define_component("dst1", gr.null_sink(gr.sizeof_int))
-	sfg.define_component("dst2", gr.null_sink(gr.sizeof_int))
-	sfg.connect("src", 0, "dst1", 0)
-	sfg.connect("src", 0, "dst2", 0)
-
-    def test_012_connect_type_mismatch(self):
-	sfg = gr.simple_flowgraph()
-	sfg.define_component("src", gr.null_source(gr.sizeof_int))
-	sfg.define_component("dst", gr.null_sink(gr.sizeof_char))
-	self.assertRaises(ValueError,
-	    lambda: sfg.connect("src", 0, "dst", 0))
-
-    def test_013_validate(self):
-	sfg = gr.simple_flowgraph()
-	sfg.define_component("src", gr.null_source(gr.sizeof_int))
-	sfg.define_component("dst1", gr.null_sink(gr.sizeof_int))
-	sfg.define_component("dst2", gr.null_sink(gr.sizeof_int))
-	sfg.connect("src", 0, "dst1", 0)
-	sfg.connect("src", 0, "dst2", 0)
-	sfg.validate()
-	
-    def test_014_validate(self):
-	sfg = gr.simple_flowgraph()
-	sfg.define_component("src1", gr.null_source (gr.sizeof_int))
-	sfg.define_component("nop1", gr.nop (gr.sizeof_int))
-	sfg.define_component("dst1", gr.null_sink (gr.sizeof_int))
-	sfg.define_component("dst2", gr.null_sink (gr.sizeof_int))
-	sfg.connect("src1", 0, "nop1", 0)
-	sfg.connect("src1", 0, "nop1", 1)
-	sfg.connect("nop1", 0, "dst1", 0)
-	sfg.connect("nop1", 1, "dst2", 0)
-	sfg.validate ()
-										       
-    def test_015_validate(self):
-	sfg = gr.simple_flowgraph()
-	sfg.define_component("src1", gr.null_source (gr.sizeof_int))
-	sfg.define_component("nop1", gr.nop (gr.sizeof_int))
-	sfg.define_component("dst1", gr.null_sink (gr.sizeof_int))
-	sfg.define_component("dst2", gr.null_sink (gr.sizeof_int))
-	sfg.connect("src1", 0, "nop1", 0)
-	sfg.connect("src1", 0, "nop1", 2)
-	sfg.connect("nop1", 0, "dst1", 0)
-	sfg.connect("nop1", 1, "dst2", 0)
-	self.assertRaises(RuntimeError,
-	    lambda: sfg.validate ())
-    									       
-    def test_016_validate(self):
-	sfg = gr.simple_flowgraph()
-	sfg.define_component("src1", gr.null_source (gr.sizeof_int))
-	sfg.define_component("nop1", gr.nop (gr.sizeof_int))
-	sfg.define_component("dst1", gr.null_sink (gr.sizeof_int))
-	sfg.define_component("dst2", gr.null_sink (gr.sizeof_int))
-	sfg.connect("src1", 0, "nop1", 0)
-	sfg.connect("src1", 0, "nop1", 1)
-	sfg.connect("nop1", 0, "dst1", 0)
-	sfg.connect("nop1", 2, "dst2", 0)
-	self.assertRaises(RuntimeError,
-	    lambda: sfg.validate ())
-										       
-if __name__ == "__main__":
-    gr_unittest.main()