CODEWITHSUNDEEP
haskelloperators
user1072605
user1072605

Reputation: 99

Haskell operation "+" what does that mean?

The code as follows:

chop [n] lev = [n-1]
chop (n:m:xs) lev = n-1:lev +m:xs

what does n-1:lev +m:xs mean?
I know m:xs is list, how can a list add a int (n-1:lev)?

Thanks you!

Upvotes: 1

Views: 150

Answers (1)

J. Abrahamson
J. Abrahamson

Reputation: 74384

The (+) associates more tightly than the (:) does. If we write that function with some more parentheses it'd be

chop [n]          lev = [n-1]
chop (n : m : xs) lev = (n-1) : (lev + m) : xs

So when the list has 2 or more elements chop modifies the first two. If it has just one element then only that one is modified.

Upvotes: 11

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