Destructuring assignment refers to the process of unpacking a data structure into separate variables. In Haskell, this can be achieved through pattern matching. Here are some examples:
1. Destructuring tuples:
`` haskell
-- define a tuple
myTuple = ("John", 30)
-- destructuring assignment
(name, age) = myTuple
-- printing the variables
putStrLn $ "Name: " ++ name ++ ", Age: " ++ show age
Output:
Name: John, Age: 30
2. Destructuring lists:
-- define a list
myList = [1, 2, 3]
-- destructuring assignment
[x, y, z] = myList
-- printing the variables
putStrLn $ "x: " ++ show x ++ ", y: " ++ show y ++ ", z: " ++ show z
Output:
x: 1, y: 2, z: 3
3. Destructuring custom data types:
-- define a custom data type
data Person = Person {
name :: String,
age :: Int
} deriving (Show)
-- define a person
myPerson = Person { name = "John", age = 30 }
-- destructuring assignment
Person { name = personName, age = personAge } = myPerson
-- printing the variables
putStrLn $ "Name: " ++ personName ++ ", Age: " ++ show personAge
Output:
Name: John, Age: 30
``
By using destructuring assignment, we can easily extract the components of a complex data structure in Haskell and work with them separately.