Paste: aoc09

EBNF: adv
[=[
escapedgarbage = "!" .
garbage-elem = !(">") ( escapedgarbage~ | . )
garbage = "<" (garbage-elem* => [[ flatten ]]) ">"
elem = garbage | groups
nonemptygroups = elem (","~ elem)* => [[ first2 swap suffix ]]
groups = "{" nonemptygroups? "}"
]=]

: cost ( level node -- cost )
  dup first "<" = [ 2drop 0 ]
  [ [ dup 1 + ] dip second [ cost ] with map-sum + ] if ;
: p1 ( str -- cost )
  adv 1 swap cost ; 

: garbage-count ( node -- count )
  dup first "<" = [ second length ]
  [ second [ garbage-count ] map-sum ] if ;
: p2 ( str -- cost )
  adv garbage-count ;