extra/sequences/interleaved/interleaved.factor

   1 ! Copyright (C) 2018 John Benediktsson.
   2 ! See https://factorcode.org/license.txt for BSD license.
   3
   4 USING: accessors kernel math math.order sequences
   5 sequences.private ;
   6
   7 IN: sequences.interleaved
   8
   9 TUPLE: interleaved { seq read-only } { elt read-only } ;
  10
  11 C: <interleaved> interleaved
  12
  13 M: interleaved length seq>> length dup 1 - + 0 max ;
  14
  15 M: interleaved nth-unsafe
  16     over even? [
  17         [ 2/ ] [ seq>> ] bi* nth-unsafe
  18     ] [
  19         nip elt>>
  20     ] if ;
  21
  22 M: interleaved like seq>> like ;
  23
  24 M: interleaved new-sequence seq>> new-sequence ;
  25
  26 INSTANCE: interleaved immutable-sequence