1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
|
{-# LANGUAGE RebindableSyntax, NoMonomorphismRestriction #-}
-- From https://ocharles.org.uk/blog/guest-posts/2014-12-06-rebindable-syntax.html
import Prelude hiding ((>>), (>>=), return)
import Data.Monoid
import Control.Monad ((<=<))
import Data.Map as M
addNumbers = do
80
60
10
where (>>) = (+)
return = return
(>>) = mappend
return = mempty
-- We can perform the same computation as above using the Sum wrapper:
someSum :: Sum Int
someSum = do
Sum 80
Sum 60
Sum 10
return
someProduct :: Product Int
someProduct = do
Product 10
Product 30
-- Why not try something non-numeric?
tummyMuscle :: String
tummyMuscle = do
"a"
"b"
ff = let
(>>) = flip (.)
return = id
arithmetic = do
(+1)
(*100)
(/300)
return
-- Here, the input is numeric and all functions operate on a number.
-- What if we want to take a list and output a string? No problem:
check = do
sum
sqrt
floor
show
in 4
|
