Atbash Cipher

atbash.cipher.nim

import strutils, unicode

const Alpha = "abcdefghijklmnopqrstuvwxyz".reversed

proc encode*(s: string, decode: bool = false): string =
  
  var str = s.replace(" ")
  
  for i in 0..<str.len:
    if str[i].toLowerAscii in Alpha: result.add(Alpha[ord(str[i].toLowerAscii) - 97])
    elif str[i] in {'0'..'9'}: result.add(str[i].toLowerAscii)
    else: discard
  
  if not decode:
    str = result
    result = ""
    for i in 0..<str.len:
      if i > 0 and i mod 5 == 0: result.add(" ")
      result.add(str[i])
    
    
 
proc decode*(s: string): string =
  
  encode(s, true)