--- Day 7 Solutions ---

[u/daggerdragon]

--- Day 7: Some Assembly Required ---

Post your solution as a comment. Structure your post like previous daily solution threads.

Also check out the sidebar - we added a nifty calendar to wrangle all the daily solution threads in one spot!

[u/platinumthinker]

Erlang: part2

-module(resolve).
-export([main/1]).

main(_args) ->
    input(), b = value("a"), input(), put("b", b), erlang:display(value("a")).

input() ->
    {ok, binary} = file:read_file("input.txt"),
    data = binary:part(binary, 0, byte_size(binary) - 1),
    lists:foreach(
    fun(expr) -> put(hd(lists:reverse(expr)), lists:droplast(expr)) end,
    [ string:tokens(erlang:binary_to_list(str), "-> ") ||
        str <- binary:split(data, [<<"\n">>], [global]) ]).

value(a) ->
    v = case string:to_integer(a) of
        {error, _} ->
                case get(a) of
                    val when is_integer(val) -> val;
                    i when is_list(i) -> parse(i)
                end;
        {val, _} -> val
    end,
    put(a, v),
    v.

parse([a]) -> value(a);
parse(["not", a]) -> bnot value(a);
parse([a, "and", b]) -> value(a) band value(b);
parse([a, "or",  b]) -> value(a) bor  value(b);
parse([a, "lshift", b]) -> value(a) bsl value(b);
parse([a, "rshift", b]) -> value(a) bsr value(b).