3 ms·
You left a type in there! greetABunchOfPeople people people do _ sayHello println
by willurd 15y ago
You left a type in there!
greetABunchOfPeople people
people do
_ sayHello println
- meric 15y agoWhile we're at it, let's switch to haskell (delete the unnecessary people argument): greetABunchOfPeople = mapM_ (putStrLn . sayHello) Explanation: mapM_ is a function that takes two arguments. mapM_ lambda list It calls lambda on each element on list. In the greetABunchOfPeople definition, notice we only gave mapM_ 1 argument instead of 2. That means greetABunchOfPeople would have to take an extra argument for the call to execute. greetABunchOfPeople $MISSING$ = mapM_ (putStrLn . sayHello) $MISSING$
- Periodic 15y agoYou beat me to it. What I love about the Haskell version is it says only exactly what needs to be said. sayHello - get the hello message for something. putStrLn - send something to stdout mapM_ - Do these things in sequence, I don't care about the result. Together they say take a list of people, get their greeting strings and print them to stdout in order. It's hard to say it more succinctly without making things confusingly implicit.