BGL - misc problems encountered

From: Chuck Messenger (chuckm_at_[hidden])
Date: 2003-05-14 15:47:45

I've been testing out the BGL, and have found some small problems.  Is 
this a good forum to post these?  If not, please set me straight.  I 
have in mind to post more of these -- in the interest of helping iron 
out the library.  Maybe the developer list would be more appropriate?  
Or a BGL-specific list, if one exists...?

Problem 1:  In the documentation, under "Using adjacency_list", 
subsection "Custom Edge Properties", it shows a method for declaring a 
custom property tag:

 > struct flow_t {
 >   typedef edge_property_tag kind;
 > };
 >
 > struct capacity_t {
 >   typedef edge_property_tag kind;
 > };

It goes on to say that an alternative method is this:

 > enum edge_myflow_t { edge_myflow };
 > enum edge_mycapacity_t { edge_mycapacity };
 >
 > namespace boost {
 >   BOOST_INSTALL_PROPERTY(edge, myflow);
 >   BOOST_INSTALL_PROPERTY(edge, mycapacity);
 > }

In the rest of the code included in the documentation, it uses the first 
method.  Finally, it says:

 >  The file edge_property.cpp shows the complete source code for this 
example.

However, the code in edge_property.cpp is completely different -- using 
the second method rather than the first.  So, at a minimum, the final 
sentence is wrong.

I suggest the alternative methods should both be shown in the sample 
code.  I made the necessary changes to edge_property.cpp -- here's the 
diff (against Boost release 1.30.0):

78a79,88
 > #define ALTERNATE  // comment this out to see an alternate method
 >
 > #ifdef ALTERNATE
 > struct flow_t {
 >     typedef edge_property_tag kind;
 > };
 > struct capacity_t {
 >     typedef edge_property_tag kind;
 > };
 > #else
86c96
<
---
 > #endif
95c105,109
<   property_map<Graph, edge_mycapacity_t>::const_type
---
 > #ifdef ALTERNATE
 >   typename property_map<Graph, capacity_t>::const_type capacity = 
get(capacity_t(), G);
 >   typename property_map<Graph, flow_t>::const_type flow = 
get(flow_t(), G);
 > #else
 >   typename property_map<Graph, edge_mycapacity_t>::const_type
97c111
<   property_map<Graph, edge_myflow_t>::const_type
---
 >   typename property_map<Graph, edge_myflow_t>::const_type
98a113
 > #endif
125a141,145
 > #ifdef ALTERNATE
 >   typedef property<capacity_t, int> Cap;
 >   typedef property<flow_t, int, Cap> Flow;
 >   typedef adjacency_list<vecS, vecS, bidirectionalS, no_property, 
Flow> Graph;
 > #else
129a150
 > #endif
163a185,188
 > #ifdef ALTERNATE
 >   property_map<Graph, flow_t>::type
 >     flow = get(flow_t(), G);
 > #else
165a191
 > #endif
Problem 2:  edge_proprety.cpp, as included in Boost release 1.30.0, 
generates warnings under gcc 3.2.2, since it is missing a couple of 
typenames.  Here's the needed patch:
95c95
<   property_map<Graph, edge_mycapacity_t>::const_type
---
 >   typename property_map<Graph, edge_mycapacity_t>::const_type
97c97
<   property_map<Graph, edge_myflow_t>::const_type
---
 >   typename property_map<Graph, edge_myflow_t>::const_type
   - Chuck