platformsort.nim

import algorithm, strutils

proc cmpPlatforms(a, b: string): int =
  if a == b: return 0
  var dashes = a.split('-')
  var dashes2 = b.split('-')
  if dashes[0] == dashes2[0]:
    if dashes[1] == dashes2[1]: return system.cmp(a,b)
    case dashes[1]
    of "x86":
      return 1
    of "x86_64":
      if dashes2[1] == "x86": return -1
      else: return 1
    of "ppc64":
      if dashes2[1] == "x86" or dashes2[1] == "x86_64": return -1
      else: return 1
    else:
      return system.cmp(dashes[1], dashes2[1])
  else:
    case dashes[0]
    of "linux":
      return 1
    of "windows":
      if dashes2[0] == "linux": return -1
      else: return 1
    of "macosx":
      if dashes2[0] == "linux" or dashes2[0] == "windows": return -1
      else: return 1
    else: return system.cmp(a, b)

when isMainModule:
  var pf: seq[string] = @["macosx-x86-1058", "linux-x86", "windows-x86", 
                          "linux-ppc64", "linux-x86_64", "macosx-x86-1068"]
  echo cmpPlatforms("linux-x86", "linux-ppc64")
  echo cmpPlatforms("linux-ppc64", "linux-x86")
  echo cmpPlatforms("macosx-x86-1058", "macosx-x86-1048")
  pf.sort(cmpPlatforms, Descending)
  echo(repr(pf))