jwills/datafu — comment on commit 0e534bc08dca50126de012657cc22820edb17f69
File:  line 0
By dvryaboy:

btw the way accumulate() is called does let you make your exec() (or call() in datafu, I guess) just be implemented as follows :
call(Tuple input) { accumulate(input); Tuple value = getValue(); cleanup(); return value; }

(no bag unwrapping and iterating necessary, since that's done in accumulate anyway)