p8.noul

day := 8;
import "advent-prelude.noul";

puzzle_input := advent_input();

grid := puzzle_input.lines map (map int);

# Today's lesson in interpreter ergonomics: I need warnings when I shadow my
# own variables

# This is cleaned up a lot from my submission solution...

rays := \i, j -> [V(0, 1), V(0, -1), V(1, 0), V(-1, 0)] map \delta ->
	V(i, j) iterate (+delta) drop 1
	# there's redundancy here but we can't map first because `map` is eager...
	take (\[i', j'] -> grid !? i' !? j' != null)
	map (\[i', j'] -> grid[i'][j']);

submit! 1, sum! for (i, row <<- grid; j, here <<- row) yield
	# why doesn't `all` partially apply on functions...?
	rays(i, j) any (_ all (< here));

submit! 2, max! for (i, row <<- grid; j, here <<- row) yield
	product! rays(i, j) map \ray -> (
		seen := 0;
		for (h <- ray) (seen += 1; if (h >= here) break);
		seen
	)