amethyst Amethyst < AmethystCore {

  eof= ~.

  empty = -> nil

  char= .:c &{c.is_a? String } -> c

  newline =  '\r\n' | '\r' | '\n'
  line = (newline break | .)*:{it*""}

  space = <\s\t\r\n\f>
  spaces= space*
  _     = space

  lower=<a-z>
  upper=<A-Z>
  alpha = lower|upper
  alnum = alpha|digit
  digit=<0-9>
  xdigit = <0-9a-fA-F>
  word = alpha | '_'

  int = ('-'|{""}):m  ('0x' <0-9a-fA-F>+ | '0b' <01>+ | '0o' <0-7>+ | <0-9>+)[]:n {(m+n*"").to_i}
  number = int

  until(e) = ( seq(e) break 
             | ('\\':[x])? .:[x]
             )* -> x.join
  listOf(rule,delim) =  apply(rule):[f] (seq(delim) apply(rule))*:[f] -> f
                         | empty -> []
  
  find(exp)    = (apply(exp):e break | .)* .* -> e
  replace(exp) = (apply(exp)         | .)*:{it*""}


  fails = &{false}

  token(s) = spaces seq(s)
  seq(s) = _seq(s) {s}
  
  member(x) = .:a &{x === a} {a}
  true = member(true) false = member(false)  nil = member(nil) 

  clas(cls)     = member(cls)
  range_in(a,b) = member(a.. b)
  range_ex(a,b) = member(a...b)

  regch(regex) = member(regex)

  reverse(l) = {@@rev||=Hash.new{|h,k| h[k]=k.reverse }} _reverse(@@rev[@self]) apply(l):rev _reverse(@@rev[@self]) {rev} #TODO array reversal likewise
  
  parse(rule,obj,args) = {obj}[ {apply(rule,*args)}:r {self.profile_report;r}]

  nested(start,mid,end) = seq(start) apply(mid) seq(end)
}