On Tue, 02 Jun 2015 15:49:06 +0000
Alex Hammel
My version looks like it traverses the list twice, but it doesn't because laziness. Where the compiler for a strict language might make an intermediate, uppercased list, Haskell will produce the uppercase values as they are needed.
ok that's cool to know. that's why i like going over these "simple" examples. in thinking about my problem i realized that it's perfectly fine if the uneaten list comes back upper case. so i went back to the map version. actually the list comp version :-)
Incidentally, that's the same reason why the `filterMap` function you asked about earlier doesn't exist. You can just do `(map f . filter p) xs`. The values will be created lazily, with no intermediate list.
precisely what i was wondering. haven't tried out criterion yet, just installed it to try out. seems like a valuable learning tool. should be a good learning tool. Brian