Re: strutils.parseEnum is slow.

[cdome]

Ideal implementation would have hash and == inside parseEnum, but mixin stops 
working in this way. Looks like yet another bug
    
    
    import tables
    import hashes
    import strutils
    
    proc genTableForEnum[T: enum](): Table[string, T] =
      result = initTable[string, T](rightSize(ord(high(T)) - ord(low(T)) + 1))
      for i in items(T):
        # TODO: ignore holes
        result[$i] = i
    
    proc hash(s: string): Hash {.inline.} =
      hashIgnoreStyle(s)
    
    proc `==`(s1, s2: string): bool {.inline.} =
      cmpIgnoreStyle(s1, s2) == 0
    
    proc parseEnum*[T: enum](s: string): T =
      const enumTable = genTableForEnum[T]()
      enumTable[s]