haskell中包含2个函数调用的函数

Question

If I have a function that needs to call 2 functions, how can that be done in Haskell??

For example if I need 2 functions to print the first 10 and last 10 items in a list, and i want to call both these functions from within one function

Answer 1

i assume you have two functions of type

f :: a -> IO ()

eg

printFirst :: Show a => [a] -> IO ()
printLast :: Show a => [a] -> IO ()

then (because IO is a monad), you can do

printBoth xs = printFirst xs >> printLast xs

or with syntactic sugar

printBoth xs = do
    printFirst xs
    printLast xs

Answer 2

You probably want to combine the two function calls into a combined string (or list of items) and return them or output them in that same function. For instance, to print out the results of two functions:

print ("First function: " ++ (show (f 1)) ++ " second function: " ++ (show (f 2)))