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Show activity on this post. The : operator is known as the "cons" operator and is used to prepend a head element to a list. So [] is a list and x:[] is prepending x to the empty list making it the list [x] . If you then cons y:[x] you end up with the list [y, x] which is the same as y:x:[] .

It means has type, so run has type Int -> Int -> Int.

The head of a list is basically its first element. tail takes a list and returns its tail. In other words, it chops off a list's head. last takes a list and returns its last element.

In Haskell, the colon operator is used to create lists (we'll talk more about this soon). This right-hand side says that the value of makeList is the element 1 stuck on to the beginning of the value of makeList .

It is a List constructor function. It is used for prepending any value in front of the list. Regarding your question, the answer is like this ((y,_):_) because it is being used in pattern matching. The first _ is the second element of the pair and the second _ pattern matches a list.

Init Function Init works exactly as the opposite of tail function. It takes a list as an argument and returns the entire list without the last entry.

ing to "Real World Haskell" : -> has only one meaning: it denotes a function that takes an argument of the type on the left and returns a value of the type on the right.

The == is an operator for comparing if two things are equal. It is quite normal haskell function with type "Eq a => a -> a -> Bool". The type tells that it works on every type of a value that implements Eq typeclass, so it is kind of overloaded.