templates extract
  templates out
    when <{start: <=$.end::raw>}> do '$.start;' !
    when <{end: <=$.start::raw+1>}> do '$.start;,$.end;' !
    otherwise '$.start;-$.end;' !
  end out
  @: {start: $(1), end: $(1)};
  [ $(2..last)... -> #, $@ -> out ] -> '$...;' !
  when <=$@.end::raw+1> do @.end: $;
  otherwise $@ -> out !
     ',' !
     @: {start: $, end: $};
end extract

[0,  1,  2,  4,  6,  7,  8, 11, 12, 14,
    15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
    25, 27, 28, 29, 30, 31, 32, 33, 35, 36,
    37, 38, 39] -> extract -> !OUT::write