[Swig-user] Blimey! Swig macro insanity

[David B. <dav...@da...>]

So, don't ask me why, but I was sitting here thinking about the Swig  
macro preprocessor this morning and started wondering if I could  
actually write recursive functions in the preprocessor.   Well, the  
answer seems to be yes.   Check out some examples:

     %define FACTORIAL(N)
     #if N == 0
     1
     #else
     (N)*FACTORIAL(N-1)
     #endif
     %enddef

     %constant FOO = FACTORIAL(6);       // Creates a constant 720 in  
the target

Or, this one (which I especially like)

     %define %ApplyPrefix(prefix,first,rest...)
     %rename(prefix ## first) first;
     #if `rest` != ""
         %ApplyPrefix(prefix,rest)
     #endif
     %enddef

     %ApplyPrefix(yow,foo,bar,spam,grok)

If you run swig -E on this, you'll see that it generated a whol  
sequence of %rename directives.

Okay, I'll go crawl back into my cave and file this one in the  
"positively bad ideas" drawer.  Ha!


Cheers,
Dave