[Discuss-gnuradio] SWIG/C++ Template Expansion Info

[Michael Dickens]

I've always wondered why GNU Radio didn't use C++ templates for gr- 
blocks (see e.g. the 'gengen' subdirectory in gnuradio-core), since  
they generally result in much less written code.  Might partly be  
that SWIG only "recently" (as of 1.3.12 or so) added C++ templates to  
its bag of tricks?  Also might be that the SWIG interface is  
challenging at its best, let alone with something as complex as C++  
template expansion / instantiation?

Last week I hacked through both the C++ and SWIG necessities to get  
template C++ gr-blocks to expand (instantiate) correctly into shared  
libraries that work correctly with both Python and C++.  After much  
fussing, I wrote a SWIG macro (%define), similar to  
"GR_SWIG_BLOCK_MAGIC", but for template C++ class expansion into  
uniquely named GR blocks.  While the macro might not work for  
everyone (or it might, testers would be appreciated), and maybe it's  
a bit ugly to read, the steps in it make sense according to the SWIG  
documentation.

If anyone is interested I can provide more information. - MLD