Question

Beginner Haskell learner here. I’ve solved Project Euler Problem 1, sum of multiples of 3 or 5 less than 1000, but I’m looking for a “more English-like” functional representation.

I created a function called multiples

multiples::(Integral a) => a -> [a]
multiples a = map (*a) [1..]

which I’m happy with, but I wish I could say

multiples of::(Integral a) => a -> [a]
multiples of a = map (*a) [1..]

to read more like English, but I get a parse error on input `of’

I want my functional declarations to read something like:

sum of multiples of::(Type)=>Type->Type

Any hope?

Answer 1

It’s kind of silly, but you can just define “words”, and ignore the arguments in your “English” function:

by = ()
multiply a _ b = a*b

multiply 10 by 12
--120

However in your example you’re out of luck, as of is a keyword (used in case of).

By the way, here is another way of defining multiples:

multiples_of = scanl1 (+) . repeat

take 10 $ multiples_of 12
--[12,24,36,48,60,72,84,96,108,120]