Back end (part 4)

Now that we've worked out the structure of the C program 
we're going to generate, we just write it down as a bunch 
of factored quasiquotations. Here is an example quote
from the back end: 

let fstmt = <:cstmt< 
        if (stat ($str:file$, &target) == -1) {
                rebuild = 1; 
        } else {
                mtime = target.st_mtime;
        }
        $stmt:satisfy$
>>

Look familliar? 

The back end is about 70 lines of code. It just produces
C quotes isomorphic to the rule tree constructed by the 
front end.