Find the first non-consecutive number in functional way in nim-lang

Question

I'm new to nim and trying some code challenges

According to https://www.codewars.com/kata/58f8a3a27a5c28d92e000144/nim

I can solve this kata with:

import options

proc first_non_consecutive*(arr: seq[int]): Option[int] =
    for i, item in arr:
      if i > 0 and item - arr[i-1] > 1:
        return some(item)

but I'm looking for a functional way of solving this problem

Thanks.

Answer 1

import zero_functional
import std/options

func first_non_consecutive(arr:seq[int]):Option[int] =
  let x = arr --> filter(idx > 0) -->
     map((diff:it-arr[idx-1],val:it)) -->
     filter(it.diff > 1) --> take(1) 
  if x.len>0:
    return some(x[0].val)

unlike the recursive one it wont cause a stack overflow with large inputs