Haskell - too few arguments

Question

I want to write a Haskell program that calculates the sum of numbers between two given numbers. I have the following code:

sumInt :: Int -> Int -> Int
sumInt x y
   | x > y = 0
   | otherwise = x + sumInt x+1 y

But when I compile it I get the following error:

SumInt applies to arguments that are too small.

I don't understand what I am doing wrong. Any ideas?

+3

haskell

Diana 26 nov. 14 at 17:32

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1 answer

bheklilr · Accepted Answer · 2014-11-26T17:33:45+0000

You need parentheses around x+1

:

| otherwise = x + sumInt (x + 1) y

The reason is that function app binds more rigidly than operators, so whenever you see

f x <> y

This is always parsed as

(f x) <> y

and never will

f (x <> y)