commify.nim

import strutils

# use mod == 0 a lot...
proc mod0(a,b:int):bool = (a mod b) == 0

# if i try to add to "result" directly I get a SIGSEGV
# so use "res" instead.  why?
# oh yeah and there's probably a much better way to do this...
proc addCommas(s:string): string =
  var 
    slen = s.len
    res = ""
    x = 0
  for i in countDown(slen-1,0):
    x.inc
    res = s[i] & res
    if i > 0 and x.mod0(3): res = ',' & res
  return res


proc commify(n:int): string = addCommas($n)

# how to get numer of decimal places
# in the float passed in? right now we force it to 2.
proc commify(n:float): string = 
  var parts = split(formatFloat(n,ffDecimal,2),'.')
  addCommas(parts[0]) & '.' & parts[1]


proc commify(s:string): string =
  if s.find(".") == -1:
    return addCommas(s)
  else:
    return commify(s.parseFloat)


echo commify(1_000_000_000)
echo commify(1236790.12)
echo commify("123123123")
echo commify(12)
echo commify("123123123.12")
echo commify("1234.")