[ tuck size split drop = ]       is starts   ( [ [ --> b )

  [ tuck size negate split nip = ] is ends     ( [ [ --> b )

  [ 2dup = iff true
    else
      [ over [] = iff false done
        2dup starts iff true done
        dip behead nip again ]
    dip 2drop ]                    is contains ( [ [ --> b )

  [ iff
      [ say "true" ]
    else
      [ say "false" ] ]           is echobool  (   b -->   )


  $ "abcdefgh" $ "abc" starts   echobool cr
  $ "abcdefgh" $ "xyz" starts   echobool cr
  $ "abcdefgh" $ "fgh" ends     echobool cr
  $ "abcdefgh" $ "xyz" ends     echobool cr
  $ "abcdefgh" $ "cde" contains echobool cr
  $ "abcdefgh" $ "xyz" contains echobool cr