seq_from_spec( \(@site1, @site2) ) ->seq_concatmap( sub { seq_zip(map seq(split//), @_) } ) ->seq_foreach( sub { $counts{"@_"}++ } ); #### sub upto { 1 .. $_[0] } sub supto { seq(upto(@_)); } seq(1..3) -> seq_map(\&upto) -> enumerate; # 0 => 1 # 1 => 1 2 # 2 => 1 2 3 seq(1..3) -> seq_map(\&supto) -> seq_concat -> enumerate; # 0 => 1 # 1 => 1 # 2 => 2 # 3 => 1 # 4 => 2 # 5 => 3 seq(1..3) -> seq_concatmap(\&supto) -> enumerate; # 0 => 1 # 1 => 1 # 2 => 2 # 3 => 1 # 4 => 2 # 5 => 3