/*
 * Copyright (c) 2013-2014 Galois, Inc.
 * Distributed under the terms of the BSD3 license (see LICENSE file)
 */

module Cryptol where

type Bool = Bit
type String n = [n][8]
type Word n = [n]
type Char   = [8]

take : {front,back,elem} (fin front) => [front + back] elem -> [front] elem
take (x # _) = x

drop : {front,back,elem} (fin front) => [front + back] elem -> [back] elem
drop ((_ : [front] _) # y) = y

tail : {a, b} [1 + a]b -> [a]b
tail xs = drop`{1} xs

width : {bits,len,elem} (fin len, fin bits, bits >= width len) => [len] elem -> [bits]
width _ = `len

undefined : {a} a
undefined = error "undefined"

splitBy : {parts,each,elem} (fin each) =>
  [parts * each] elem -> [parts][each]elem
splitBy = split

groupBy : {each,parts,elem} (fin each) =>
  [parts * each] elem -> [parts][each]elem
groupBy = split`{parts=parts}