include "NSLog.incl"

CFArrayRef local fn ForwardDifference( arr as CFArrayRef )
  CFMutableArrayRef result = fn MutableArrayNew
  for NSUInteger i = 1 to len(arr) - 1
    CFNumberRef diff = @(dblval(arr[i]) - dblval(arr[i-1]))
    MutableArrayAddObject( result, diff )
  next
end fn = result

CFArrayRef local fn NthForwardDifference( arr as CFArrayRef, n as NSInteger )
  if ( len(arr) == 0 ) then return @[]
  if ( n == 0 ) then return arr
end fn = fn NthForwardDifference( fn ForwardDifference( arr ), n - 1 )

void local fn DoIt
  CFArrayRef initialArray = @[@90, @47, @58, @29, @22, @32, @55, @5, @55, @73]
  for NSInteger i = 0 to 9
    CFArrayRef diff = fn NthForwardDifference( initialArray, i )
    NSLog(@"[%@]", fn ArrayComponentsJoinedByString( diff, @", " ))
  next
end fn

fn DoIt

HandleEvents