| Related to this is the importance of deforestation. Some good links: * http://en.wikipedia.org/wiki/Deforestation_%28computer_scien... * http://www.haskell.org/haskellwiki/Short_cut_fusion Deforestation is basically eliminating intermediate data structures, which is similar to what the "int(s.split("-", 1)[1])" versus "atoi(strchr(s, '-') + 1)" slides are about. If you consider strings as just lists of characters, then it's basically a deforestation problem: the goal is to eliminate all the intermediate lists of lists that are constructed. (It's something of a peculiar case though, because in order to transform into the C code you need to not only observe that indexing an rvalue via [1] and throwing the rest away means that the list doesn't have to be constructed at all, but you also need to allow strings to share underlying buffer space—the latter optimization isn't deforestation per se.) I don't know if there's been much effort into deforestation optimizations for dynamic languages, but perhaps this is an area that compilers and research should be focusing on more. On another minor note, I do think that the deck is a little too quick to dismiss garbage collection as an irrelevant problem. For most server apps I'm totally willing to believe that GC doesn't matter, but for interactive apps on the client (think touch-sensitive mobile apps and games) where you have to render each frame in under 16 ms, unpredictable latency starts to matter a lot. |